When I took my kid to the guitar center ,everyone was.looking the tube amps better ,you do nice.work ,but if it was my amp .I would have thrown the selenium rectifier as far as I could throw it .not a fan ,but I understand why you leave them in ,and you are the expert .I wish most people ,would understand neatness counts ,like the amazing work you do .
Thanks, Ron. On valuable, original amps it's best to keep as many original parts as possible. The selenium rectifier is for the bias circuit and was working perfectly, so I left it in. These decisions are made after consulting with the owners of the amps.
I have watched this series a few times now and it just donned on me that my scratch built 5F10 Harvard has the exact same input scheme as the Vibrolux. I guess I will be doing some soldering tomorrow. Thanks, Doug.
I also own a Tele and could tell it was the mystery guitar. You could tell that amp was a match to the Tele. This latest project series is as good as it gets! It is a virtual look at an excellent repair/restore of an amazing tube amp. The owner will be very pleased, as usual. Can't wait for your next installment. Thankz
You're welcome, ATL, and thanks for the very nice comments. The owner has already signified his approval, so it looks like the project has been a success. The re-coning video should be out soon.....if I ever get the parts.
Honestly, I didn't care much for the bridge pickup and didn't like the neck pickup at all, but combined was sonic bliss, or at the very least a great usable sound to my ears. Never cared for the muddy combined sound on my Les Paul's. The Tele however was nice and clear and punchy as well. BTW, a great video as usual. Looking forward to the re-cone.
As always, Rusty and Jack have produced a top notch video! Not too shabby yourself Uncle Doug! Thank you again for passing on your vast knowledge of these fine tube amps, it is a great learning experience.
Hey Uncle Doug thanks so much for sharing. If you only knew how many times I've said how I wish you were really my uncle Doug, because I would be a daily visit just wanting to learn all you have to offer. I'm just fascinated with your knowledge. Thanks again
Thanks Uncle Doug. i always enjoy your videos. i remember getting the chance to record with a '58 Deluxe. i'm more of a bassist than a guitarist, but i can tell you that my 80s Squier Telecaster never sounded better.
I just want to thank you for your expertise and taking valuable time for these wonderful and educating videos. I am semi retired at 65 and have time for learning electronics which I was always interested in. I have been repairing old tube radios and cant wait to build one of your amps. This is exactly what I was looking for. You have a knack for explaining and thank you again for sharing your knowledge. Love the humor with the pets. Please keep doing these. thanks Terry
Hey Uncle Doug, this video series really helped me out in building my own 5f11 vibrolux kit. I paused the video at strategic points and tried to copy Lupe's neat and tidy wiring as close as possible. The amp turned out great. Thanks for your generosity in sharing your tube amp knowledge in layman's terms on so many occasions.
Awesome videos, Uncle Doug ! I've just found your YT channel on my recommended list, and watched almost everything by now. I've worked 3 years on a local workshop here in São Paulo, Brazil building mainly Fender Tweed era replicas, but it has been a while since I'm "retired" of working in electronics (it gave me a huge problem that causes me terrible back pain) but sometimes I mess around with it as a hobby. Wish I've had known your channel back then, it would be very helpful at that time. I'm writing in this specific video because I've built for my personal use a Vibrolux 5F11 replica, and it works like a charm, but I've never noticed that flaw on the input scheme ! So, thank you very much for pointing that so I can add the 100k resistor in the input just as you did and save myself from some future headache ! Cheers for you, Rusty and Jack !
It never ceases to amaze me how long a new speaker takes to break in. I broke in 4 Celestion Greenbacks ( Real ones, Heritage G12H made in England) in a Marshall 4x12 played regularly with a JTM45. I got a price on 5, and put one in a 74 Deluxe Reverb. 4 years later, the Deluxe Reverb became my number 1, after hardly being played with the new speaker. I swapped out the DR speaker with one from the 4x12 and the difference was unbelievable. The Moral of the story is never judge a speaker before it is broken in, which is going to take at least a year I reckon.
I agree, Paul. I will add that this Special Issue speaker, out of the box, is a lot closer to being broken in that a plain P10R. The plain one tends to be rather harsh and brittle.....and doesn't improve all that much with use.
Thanks for the reply, Doug! I kinda guessed at Fender, not because of the sound, but because of the amp! My Fender Strat sounds a bit different, so again I thought 'maybe a Tele'! Keep these shows coming, I really enjoy listening to you explaining things! Have a good Sunday! Ben (Eccles Radio U.K.) here on the internet!
I Like the Idea you are giving back the old parts so that the person can have a option. I am fooling around with a 61 Princeton amp and one of the resistors in the bias circuit looks burnt. I am going to take another peek at this video when I address the problem. Great Info Doug Thanks c];-D
You want to keep them working with minimal alteration, AL, and retaining the old (defective) parts with a vintage amp reduces the harm when repairs are unavoidable.
Uncle Doug, GREAT series here and quite helpful to me personally, I have a 1956 Vibrolux with "Lily" on masking tape in there, completely original except for me switching out the diode and adding the 100k resistor to ground in the input section. Alas I was unable to turn up a pic of Lily. THANKS for all you do!
I just want to say that you have been a HUGE help to me with your videos, I have learned so much over the last year or so watching you teach. I have a band with my wife named Adrianna Marie and her Groovecutters, very 40sish blues music. I would like to send you a CD of our material. If you want one please send me you mailing address to lajones@lajones.com. Thanks again, I look forward to more learning from you! LA Jones
Hi Uncle Doug & Family, Very nice resto-mod on the '57. You truly are the master! Learning a lot, way more to go. It sounds fantastic, I'm sure the owner will be quite pleased. Wishing you and yours all the best, take care, C.
Hi Doug. Fantastic job on the Fender Amp ! I hate to see the end of this series. What are the odds that, Jack and Molly have the same small tuff's of whit hair on their neck and belly ?. Amazing. Back to the Amp it's sounds and looks great ! Bravo Doug !. The Desert part in your other video was awesome to say the least. I don't comment every time has I figure you are busy and I do it out of respect,not because I am to busy or lazy. Just know I appreciate each and every video from you. All my very best to you and yours Bobby Molly and my wife
When it comes to changing parts or making circuit alterations to an amp I really like your approach. It is thought through and done so carefully that, if desired, the amp could be returned to exactly how it was when you received it (I'm not advocating you blow the voice coil out). I believe Lupe would be very pleased to see your work and Leo would give a thumbs up to your circuit corrections. The tremolo does lack depth though, not in the same league as Uncle Doug's Tremoverb. I have tried watching videos by other amp repairers but for the most part have given up in frustration. The subject is interesting but they either swish up and down the amp like the camera is a spray gun or they go in and replace more components than is reasonably necessary. They should watch how you do it. Hope the re-coning parts arrive soon so you can make yet another video for us to enjoy. Then all we need is someone who would like you to "Take a look at his 5E9-A Tremolux......". All the best, Jeff.
Thanks so much for your very nice comments, Jeff. Rusty and I are proud of our work and really appreciate it when others are too. I have my fingers crossed.....both for the arrival of the re-coning supplies, and for someone to send a Tremolux for service :)
When I worked at Ernie Ball Music Mann years ago, a lot of Fender and Music Mann Amplifier history went to the land fill. Wish I did some dumpster diving. Too bad we do not make tubes in this country anymore. There is still a need for tubes (valves) in audio, and ham radio applications. Nice views of desert. Flew over many time while flight training at ELP and LRU.
I would love to have hijacked a few of those trucks headed for the dump :) Just about all of our manufacturing has been sent overseas, so I guess it's no wonder that vacuum tubes went there too. The desert you flew over is only 30 to 40 miles to the east of where the video was made.
OK, the mystery guitar was an early Telecaster, with that crazy treble dump on the neck pickup that nobody ever used. Leo got so much right that he can be excused the odd blip. He changed guitar playing for ever, and couldn't even play himself. Thank you Leo. Thanks Lupe, and a special round of applause to Rusty for his, (literally), boundless enthusiasm. Sadly missed. Oh, and to our favourite uncle, natch. Hogwarts' finest alumnus. Thank you all...
You are most welcome, sir. Your videos have been a much appreciated distraction in these 'strange times'. I'm even in danger of learning something about these dark arts. (I thought it was a '51, but hey... Close gets no cigar)... Long may you continue to edutain us and restore all things electronic and feline to fine fettle.
Uncle Doug, thanks for another enjoyable video, the amp sounds amazing and I can't wait for the re-cone-ing video. Always have been interested in that actually. Buddy
Finally catching up! This is great. I will probably build a clone of this to donate to a fundraiser this winter (I built a 5C1-clone in a 5F1-style cabinet, complete with shellac'd-by-me tweed, least year for the same fundraiser). FWIW, I think this amp has the BEST tremolo! I like it on the subtle side. Reverb, on the other hand... that s**t need to be swampy :-) Kudos, Doug! And keep 'em coming!
Thanks, Jason. It's great to hear from you. Rusty and I applaud your generous contribution to charity.....very commendable. We promise lots of new videos once some chores and other hobbies are dealt with.
Great series very informative and entertaining wouldn't expect less from You, Rusty and Jack. I'm looking forward to the speaker rebuild I hope you put it in a cab so we can hear it. Thanks for your efforts you really help us amateurs :]
You're welcome, Mike. The re-coning video is uploading as we speak. The testing is done without a cabinet, but I think you'll agree that it is adequate.
Thanks, Greg. The guitar is a '52 Fender Telecaster re-issue which has the original tone cap for the neck pickup.....making the tone a bit muddy. Newer Tele's have a different tone cap for this pickup.
Great video as alway Doug as I am an Ampliholic and a Teleholic I was onto your mystery guitar straight away that muddiness at the neck is a dead giveaway, easily adjusted with the right PIO cap, one of the reasons Fender supply a spare with the 52 reissue I think!
yep spot on Doug I have a 52 reissue, a 52 Hot Rod and a Cabronita, plus I have fabricated a couple of partscasters for friends, I just think they are the perfect working musicians guitar :)
The schematic marking with "+" at the selenium rectifier's cathode (6:45) reflects the typical marking seen on the part itself. I suppose the reason is that positive DC voltage will appear on that terminal.
Not really, I think they were just following the established practice. You still see that today in silicon bridge rectifier packages that have + and - marked at the DC outputs.
I'm not talking about selenium or bridge rectifiers, I'm talking about simple diodes. Fender labels diodes with the banded, cathode end + and the anode end -. In my experience, this is not established practice.
Thanks, Colin. I was worried that the excellent tone might not survive my primitive recording process, but it came through about 80% intact. In person, this little gem sounds even better....especially with single coil pickups.
it absolutely sounds amazing and i know what you mean about the imput Jack's, and the atom sprage capasitors ar one of the best I think. great job sounds good keep it up
Thanks for the informative and entertaining videoes,Doug. Maybe you could pound out some tunes out in the desert on one of your favourite amps sometime!
Amazing work, as always! Sounds great and looks great! I'm gonna guess that was a tele the second time around? Thanks for all the hard work you put into your channel and all of your projects!
Uncle Doug, I searched your videos but could not find one that covers my questions completely. I have a 1959 vintage Tweed Bassman that is blowing fuses. In the past (two other times in my 1960 Bassman) it was the GZ34 rectifier (expensive NOS Mullard) tube that was going bad. I have a unique filtering setup as per Gerald Weber which is way higher that the max 60uF spec of the GZ34. But, Gerald does other things to minimize the strain on the rectifier. I have not had many problems but I suspect it is the extra load on the tube that causes them to eventually wear out. I have thought about doing two new mods when I get my new modern JJ GZ34 and diodes. I was thinking of replacing the selenium rectifier with a IN4007 diode and was told I don't need to put a resistor in series with it. Some circuits may require the resistor. I have an adjustable bias installed so I am assuming I can just put the diode in place of the selenium rectifier and be done with it. What do you think? Another mod I was thinking of doing was adding two IN5408 (3A) diodes in line with the 325VAC coming from the PT to the rectifier socket (pins #4 & 6). I was told this can take some of the stress off of the tube by "pre-rectifying" the AC voltage. What do you think about that? I've found schematics online that show using pins 5 & 7 as solder points and then bridging the diodes from pins 5 to 4 and 7 to 6. Thanks for your help.
It appears that the modifications you installed have unpleasant side effects. Personally, I would return the amp to its original configuration and enjoy it as it was intended to be. Excessive filter capacitance causes way more harm than good, as you have discovered. Yes, you can replace the selenium rectifier with a diode....it's a common improvement.....but you will then have to adjust the output tube bias due to the probable increase in -DC voltage to the grids. Adding the diodes to the rectifier pins is another fairly common alteration, but it does not reduce the stress on the rectifier, since the stress is a result of excess initial current flow (due to excessive filter capacitance) not the "stress" of rectification.
@@UncleDoug Yes, the higher filtering is debatable. I have not had any real issues with it because Gerald bypasses the standby switch and pre-charges the main filter caps while the amp is still in standby mode. He says that reduces the surge on the GZ34 but still, I have blown three (maybe) now over a 10 year period so it is tolerable. But, I may just go with the blackface filtering and put two 100uF/350V caps in series for 50uF/700V. I think I have a couple of 100uF/350V caps. I read one place where the resistor in series with the IN4007 on the bias supply is necessary to reduce available surge current but I think that is a different situation in the B+ side of the circuit and not the bias supply side. What is the advantage of adding the diodes on the rectifier socket then? I also read that the selenium rectifiers can start blowing fuses too when they age. Mine are all the original seleniums. PS. The high filtering is only necessary if you play the amp very loud which is supposed to keep the notes in tune according to tests done by Gerald many many years ago. I do play my amps loud but don't gig with them anymore so I could go back to lower uF.
@@millstap Sadly, many modifications are done simply for the purpose of changing something. If Fender really thought that larger filter caps would provide noticeably better tone, they would have installed them, even if it cost a few more cents. This explains the diodes on the rectifier pins: dynacotubeaudio.forumotion.com/t1006-tube-rectifier-yellow-sheet-diode-mod
@@UncleDoug Thanks for the help Doug. Fender did feel the need to change the filtering in the Bassman in the '59 Reissue so they must have figured out the 40uF/600V was inadequate. They beefed up the voltage rating in the AB763 circuit in the '60's to 35uF/700V. But, in the new '59 Reissue Bassman they went with two 100uF/350V caps in series for 50uF/700V. I will go with the Reissue specs and see what I think. I did see that article about the rectifier diodes so I'm glad to know you are referencing the same forum thread.
Hi Uncle Doug, Bravo! Excellent final episode to the series! Could that anomaly in the first input jack have caused the speaker to blow? Folks as I stated before don't forget to "like" this video by clicking once on the thumbs up image at the bottom right of the video screen. It is the only way to thank "Uncle" and his buddies, Jack and Rusty, for this complimentary and pleasurable viewing fun, entertainment and especially the educational value so skillfully presented within the matrix of the production! Many thanks of appreciation! I just wish there were other ways to show my thankfulness? Kind Regards, Steve
You're welcome, Steve, and thanks for all your very nice comments and "thumbs up" support. I have no doubt that if you were operating the amp at relatively high volume on Input 2 or 3 and then switched to Input 1 the speaker would be damaged. I'm not sure if it would have been blown to pieces like it was, but it would most likely be blown. I have no idea how this input design was ever acceptable. Re the "thankfulness" please see the note at the end of the video notice sent to subscribers re Patreon. This channel has become a "full-time job", so Rusty and I decided to follow the advice of some viewers and allow people to contribute if they wish to show their support for our efforts......and provide Rusty with some higher-grade, lower-calorie food :) Our Patreon site is "Uncle Doug and Rusty". Thanks again :)
Hey Doug, great video as always; your videos are truly an education. However, I'm not so sure about your analysis of the input circuit starting at 12:39. I agree that when you connect to input one only there is no grid leak resistor (except that of course the guitar itself will act as a the grid leak resistance). When you connect to input 1 you get the full guitar output voltage to the grid. When you connect to input 2 you get 2/3 guitar voltage to grid and when you connect to input 3 you get 1/3 guitar voltage to grid. In the case of input 2 you get 68k to ground and in the case of input 3 you get 34k to ground (ignoring the resistance of the guitar). This is all assuming you only connect one guitar to the amp at one time.
Thanks, Dave. I will agree that, when plugged in, the guitar volume control could provide the ground reference needed for tube bias.....but I stand by my analysis of the input impedance. I believe you're ignoring the collective effect of all 3 grid blocker resistors. In actual testing, attaching an ohmmeter to each (ungrounded) input leaf will yield about 100K impedance to ground for all three inputs (including No. 1, now that the 100K resistor was added). To me, an infinite input impedance is simply not practical or usable. I added a note to the video about the guitar volume control providing bias reference, and explaining that the impedance for Input 1 can be tailored to your needs simply by adding a higher or lower value resistor. Thanks again for your input.
OK, we seem to be reading the schematic differently. I have drawn out my interpretation and posted it here i63.tinypic.com/sm3o04.jpg It seems to me there is a potential divider effect for inputs 2 and 3. Please do take a look and let me know your thoughts. By the way, I wasn't defending the lack of grid leak resistor on input 1, just making an observation. Regards.
Thanks for your careful analysis, Dave. I agree that if a guitar is connected to the amp, it, in effect, becomes part of the circuit and provides the impedance to ground missing in the amp circuit. My analysis was purely of the amp circuit itself. I repeated my impedance (signal to ground) measurement of the 3 input jacks with a "mock guitar" (230K volume pot, signal to ground) plugged into each jack. Results with the added 100K resistor: 1 = 69K, 2 = 74K, 3 = 74K. Results without the added 100K resistor: 1 = 230K, 2 = 74K, 3 = 74K. Results with an added 220K (instead of 100K) resistor: 1 = 111K, 2 = 74K, 3 = 74K. As a result of these measurements, I'm going to change the 100K added resistor to 220K, giving the 1st input jack a reasonable amount of higher gain than 2 and 3.
The amplifier has a great tone! But, I can hear the delay in the tremolo. That has to be uncomfortable for players that are used to the quick response and thick tremolo. Again, it saved Fender from using an extra tube and components. That input circuit design was a bad move on Fender's part, but is easily modifiable...Changing the resistor for the first input jack is a mod I always make. That Telecaster sound is recognizable from New Jersey :) Even tough I'm not a guitar player, each guitar has it's own distinct sound that can be heard instantly. My instrument is the Hammond B3 Organ (jazz organist) it's hard to do the real world tone test on an amp for me in the shop. I usually ask the customer to bring his ax for the final listening test. Excellent 3 part video. :)
lovely amp. I love tweeds. Does anyone know why fender didn't replace tube rectifiers in all thier amps with solid state diodes? Tube rectifiers survived in Deluxe Reverbs and some Pro Reverbs even through the CBS cost cutting...I can't help wondering why. Especially as GZ34 tubes offer little if any sag.
Thanks, Paul. I think Fender was rather conservative about radical changes and, let's face it, almost all low to medium output amps in the 50's and 60's were tube rectified. It may be "old fashioned" but it was part of the tone that people sought.
I have a 1960 Vibrrolux and would love to have a schematic for it. since it is all original. Could you send me a link to where i could download the schematic at?
Uncle Doug you are such a good teacher and might even have a mild case of geniusitis. Your delivery is such that most, that is ones with half a brain, can understand and more importantly in an inviting way captures my interest. I love the breaks, or comedic relief, with Rusty and Jack. I am guessing that Rusty may no longer be with us and that would be a sad thing if true. I am a true-blue pet lover (who happens to struggle a bit with depression) and couldn't get by without my golden doodle (Jarvis). I spend a lot of my extra time watching your videos and I can't wait for your next series. If I were closer I would bug you to let me come apprentice at your side because your teaching style meshes very well with my learning style. Anyway... another great mini series by you and your comrades. Hope you are enjoying your sabbatical, lol.
Thanks so much for your many nice comments, Scott. We are indeed enjoying our break from video production, but do intend to return when a great topic and sufficient inspiration are discovered.
Your welcome UD. FYI, my first project is a 1965 Kalamazoo model 2 that I bought very cheap. It has a 1/2 12AX7 driving the tremolo. Pretty cool. It works but needs some love and thanks to you I feel confident enough to dive right into it.
Telecaster!! Beautiful work, and a gorgeous sound. Subtle would be a good description of the tremolo. :)) A nice trick with the tubing on the studs. I think Jack was resting up from all the hard work filming and editing a great series. Thank you. Andrew
Thanks so much, Andrew. Yes, indeed.....a '52 reissue in fact. Glad you liked the tubing idea.....I also use this on desert vehicles to keep them from disassembling themselves 20 miles out in the dunes. The tremolo is subtle, but it still trems its little heart out :) Jack is like an alligator sunning himself on a river bank.....just when you think he's either dead or asleep, he jumps up and runs around the house like a lunatic.....much to our amusement :) You're welcome.
We've been considering getting some t-shirts made with a goofy Uncle Doug and Rusty logo, Lincoln. There are some Internet companies that will make, sell, and ship them. If I get a chance, I'll check into it.
Tone demo sounds real good with that new jensen. I hear smome old familiar guitar strains and riffs, but I can't place them anymore..too much water passed under the bridge as they say. First guitar must be a strat? drastic tone difference between neck and bridge on the second...definitely tele or at least some form of it.
First guitar had humbuckers, second was a '52 Tele re-issue, in which the neck switch position activates a tone-modifying cap to emphasize bass tones. This is how they were originally wired.
Hi Uncle Doug, I love watching these AWESOME video's, and have been doing so for the last 6 months. I'm so impressed that I went and purchased the guts of an old Thomas/Leslie organ that came equipped with about 80% of what I need to build my own amp. My Traynor YGM-4 Studio Mate (yes, I'm a Canuck from Montreal) is just too big to lug around, so "compact and portable" is the new mantra. This Vibrolux is the one I have my heart set on building, the box is done, but after winning the staring contest with the underside of the organ chassis, I discovered my power transformer has only 2 ground leads and 8 others. Before I make a terrible assumption, I want to check with you to see if it matters if I use either of these ground leads to connect to the 10 K resistor before the diode? As an aside, why do we feed back the output from the speaker signal back into the second 12AX7 cathode? Thanks, Alf
Thanks for your nice comments, Alf. The two ground leads are probably the centertaps for the high-voltage and the 6.3VAC windings. Both must be grounded. I don't understand why you would want to connect either of them to a resistor or diode. The return to the cathode from the output is a negative feedback loop. I have posted a video that explains how it works. In general, it compresses the output signal, "cleans up" the signal, and reduces excessive volume.
Thanks for writing back, you're a pal. Upon closer examination of the power transformer and a review of your video on how to identify transformer leads, I discovered I'm missing that high voltage bias supply, so I'm going back to the 5E3 Fender Deluxe and I'll see if I can find a mod to add a tremolo circuit. Give Rusty a nice pat for me.
Hi Uncle Doug, I watched that video you did on the single variable trim pot you insert on the Princeton Reverb with the diode to negative bias both grids and it really enlightened me, it assumes both tubes are matched. I've decided after watching the two part bias videos again that I'd prefer to have two trim pots to cathode bias each of the two 6V6 output tubes, the design is simpler. The Tremolux uses this approach and I like the sound of that amp with a bit more of it's mid to bass tone and over-driven blues tone, so I'm going to proceed to clone that one and let you know how it goes. If you ever get up our way to a Jazz Festival, or any summer festival, the beer and popcorn are on me. You're the master.
Good luck with your project, Alf. Let us know how it turns out. Also, you better watch what you're offering.....Rusty has been known to consume prodigious amounts of beer and popcorn, so you'd better have a healthy limit on your credit card :)
Howdy Uncle Doug. I know I'm about 6 years late with this comment, but I wanted to point out that I know a number of techs who, like I, have had BAD experiences with Sprague Atom electrolytic caps. They just don't hold up very well over time in my opinion. I know there's a great deal of hype about their supposed incredible quality, but I'd argue it's really just hype. I had 5 in an old Vibrolux Reverb dated from 29th week of 2010. This amp hasn't been used for more than a total of 20 hours in the last 11+ years since those caps were made and I had one fail this week (Feb 2022). The amp has lived in dry, sunny-southern California all this time and not been exposed to cold or humidity. I decided to cut open the 16uF Atom that just failed and I can tell you that inside, the dielectric is rather puny when compared to the blue cover; it was about 1/4" shorter and maybe 3/5ths the diameter. Not nearly as impressive is the big blue exterior shell! I simply don't use Sprague Atoms anymore. I've been using MIEC caps with much better luck, FWIW.
I share your opinion, Leon, and have ceased to use Sprague Atoms, largely due to their unreasonably high price for rather dubious quality. My go-to caps now are F&T's.
This trem may not have the awesome psychadelic wobble we're used to, but at moderate levels the delayed onset makes it far more musical and doesn't randomly remove attack.
I put the nuts on with a deep socket, alone with minimal force, so probably about the same as finger tight. I agree though, a speaker doesn't need lotsa torque to be held in place securely. Love the way it sounds. Really like the idea of a high and low gain input. On such an otherwise simple amp, you can really change the way it responds.
I agree with all you say, Lincoln. Hopefully others will heed our advice. Over the years, I have seen a few speakers permanently damaged by over-tightening. I'm glad you like the tone and hi/low inputs.
Great video as usual, wow were you ever right about the tremolo being "barely there" as compare to others you have done. I was going to guess Stratorcaster until you played the neck pickup then I figured it was probably a Telecaster. Once again Jack was brilliant demonstrating his dominance, and you were just as brilliant with your amplifier prowess.
how old is the tele? does it have the old circuitry where you can only blend in the neck pup full out but if you move the pup selector to neck only it is the tone fully off and the fake base sound? i am thinking early esquire or nocaster
Diode +/- labeling conundrum. If memory serves, if the DC voltage is measured across the diode it will read as the same polarity that is marked on the schematic. For factory checks or for troubleshooting that labeling might be helpful. Makes sense because the meter will be displaying the voltage drop across the high resistance of the diode when it is not conducting.
Hi Doug Steve for Aus again thanks for this video I had a Harvard that I was working on today guess what? same issue that pesky Diode its the same mistake on the schematic again got it right paralleled the 56k with the correct resistor hey presto -27 volts and perfect tone. BTW Jacks Australian Double known around these parts as the Black Flash is doing Just fine LOL
You're welcome, Steve. We're glad you were able to solve your diode problems. Rusty send regards to his mate, Black Flash, and invites him to join us for a nice, cold Foster's whenever he's in the neighborhood :)
Doug - You got me thinking about the impedance mismatch of input 1. I built a 5E3 and would like to fix this issue if it is present. I'm a little confused by it as when you look at the 5E3 schematic, are the arrows representing the grounds of the jacks? I see what you mean in the video looking at the vibrolux schematic but the 5E3 schematic has me confused.
The arrows are not ground. They show where contact occurs between the leaves of the input jacks. The 5E3 does not have the impedance issue seen in the Vibrolux. Both jacks have a 1 Meg ground.
Great job! Sounding the business now. I wonder how fender approached the inputs in reissues. That painting of Jack at the end was fantastic, another string to your bow? Hoping today finds you well. Keep it between the ditches!
Thanks so much, PJ. They redesigned the input circuit for the brownface and blackface amps. I'm glad you like the painting.....my wife is the artiste in our family :) All is going quite well, especially with nice viewers like you. We will :)
You're welcome, Bertus. My 8 Ohm DL appears in the video about how to measure amplifier power output. You can buy them on Ebay at a very reasonable price.
Mystery guitar sounds like a '52 Telecaster, I checked out the wiring of my 2014 Fender Mexican Telecaster, and it looks to be wired to Fender's 1966 Telecaster specs where the pickup selector is wired to allow the neck, neck plus bridge, or bridge pickup selections, with a master volume and tone control, tone cap is a .05uF ceramic, but I might swap it out for a .05uF Orange Drop or some other cap at a later date.
Probably so, SC, but to a rather extreme degree for modern instruments, especially with humbuckers. My modification has changed it into a "moderately higher gain" input.
Well, I've never understood why Fender would have 3 inputs shared by the same channel preamp input. One guitar input for normal output single coils or humbuckers for this kind of amp. For the second (say the rhythmn guitar, if one had no choice, to plug in their guitar at a HS dance, would be about all this little amp could handle. Three guitars? and the last one plugged into the high gain input..no wonder the speaker cone got shredded..i would imagine quite a feedback howl coming out this little amp. Also, were Humbuckers even available at the time the amp was designed or built around 1957 ? Gibson just started production of the PAF humbucker sometime in 1956. Was Fender even concerned about this? Gibson did have their P90 single coil on their products well before 1957 though. Interesting if one go back to discuss what they were thinking using 3 inputs on a 17-18 watt amp? with no independent channel volume control for each input...very strange design coming from Fender and we thank you for pointing out this anomaly Uncle Doug. I just can't see 3 guitars plugged into this amp and sharing the same input preamp. One guitar would probably be the norm. 3 guitars would be an invitation to disaster for this little amp.
It would be like watching an episode of "The View" on television.....with everyone trying to out-yell each other. Utter pandemonium. I don't understand the multiple inputs either....unless maybe one for guitar, one for harmonica, and one for singing????
That might have been the intent. However, having three different instruments with different outputs.. mic/harmonic/guitar would have been quite a juggling act with just one preamp and one volume control. Now if the three different input sources actually went through a mixer, each with it's own gain circuit and volume control, and then three outputs..maybe.. but then with one mixed output, why would you even need 3 inputs of the same impedance (practically), going to the first preamp tube.. One instrument input would easily over power the other two in volume. this is bizarre thinking even from a company renowned for it's practical amp designs, like Fender.
Very nice repair and alteration on this girl I would hate to think what its resale is ,the new reissues are 2 grand and more wowsa ,guess should have gone with a fender instead of gibson lol
I knew right away that the second guitar was probably a 50's or low to mid 60's Tele. I have a '67 Tele (which I bought brand new) that was one of the last to have Leo's "dark circuit" in the neck position. This was supposedly to allow the guitar to sound like a bass if needed. I have so far resisted the urge to mod it from the original design.
Yes, it was a '52 reissue. I have no idea why Leo would want a Telecaster to sound like a bass guitar.....but so far I've left my "dark circuit" intact too.
Like a hyperactive child, he has periods of wildly running around the house.....followed by long naps. Actually, not a bad lifestyle, other than the wild running :)
Hello Dear Uncle Douge and Rusty, first of all thanks for share your know how with us. I'm assembling my first tube amp (Rick-Tone Jupter) and it's not easy to find some parts like axial capacitors and tube valves. May you suggest us a store (web site) where we can buy these parts (specially axial capacitors)?
You're welcome, Thiago. We're glad the videos are helpful. I order all of my electronic parts (except transformers) from Antique Electronic Supply in Tempe, AZ They have a nice website that you can order from online.
Doug - I found a Fender Bassman ( stamped 1971 inside the chassis) and I am having trouble finding the right circuit. The serial is a61xxx so I know its either Ab165 or aa270 perhaps. Any easy way to tell which one it is ? Someone replaced the EL caps with very wrong values and I want to get her up and running again. Any help is completely appreciated. Ron
I assume there is no tube chart in the cabinet, Ron, because that is where the circuit is generally identified (not always accurately, however). My method for differentiating between different circuits is to download the schematics for the circuits the amp could possibly be, and then comparing the component values, rectifier choice, transformer ID numbers, etc. to determine which circuit it really is. In some cases, you may have a hybrid circuit, in which more than one schematic will apply, but generally, it is quite possible to nail down the circuit's identity by carefully comparing it to the schematics. Good luck.
looking forward to the re-coning video, always a bit of a dark art to me, and i always send away for speakers to be re-coned...tried it once many years ago and totally messed it up. never tried again, so be interested to know how you go about it.
I hope the video is helpful, Sparkey. I agree that any re-cone has some possibility of error (and wasted time and money), but with a speaker like this, it's definitely worth the risk.
I got all my supplies from Antique Electronic Supply. The Sprague Atoms cost $12 apiece and the Chinese equivalents are about $3.50, so it's more like 3.5 x the price :)
Another great and informative video entry in the annals of tube amp cognizance...thanks again, Uncle Doug. Not that it was necessary on this beauty, but when you need to clean the accumulated grime from tweed (and possibly from grill cloth), what's the best approach?
You're welcome, C7. I would leave a grill cloth alone.....unless it's simple cloth and you want to remove it from the cabinet and try washing it with Woolite. For the cabinet, a moist soapy cloth will remove most of the grime.....but don't overdo it or get it too wet.
Came back to this unseen series - loved seeing an old friend and hearing the Peach Pip quip !! Great stuff as always.
Welcome back, Patrick, to the oldies but goodies.
@@UncleDoug Thanks for the unexpected response . Amazing stuff.
@@patrickmay9034 Glad you like it :)
When I took my kid to the guitar center ,everyone was.looking the tube amps better ,you do nice.work ,but if it was my amp .I would have thrown the selenium rectifier as far as I could throw it .not a fan ,but I understand why you leave them in ,and you are the expert .I wish most people ,would understand neatness counts ,like the amazing work you do .
Thanks, Ron. On valuable, original amps it's best to keep as many original parts as possible. The selenium rectifier is for the bias circuit and was working perfectly, so I left it in. These decisions are made after consulting with the owners of the amps.
Great video Doug! So many thanks for sharing your knowledge and skills! Jack and Rusty's cameos are a riot!
You're welcome, SS. Thanks for watching :)
I have watched this series a few times now and it just donned on me that my scratch built 5F10 Harvard has the exact same input scheme as the Vibrolux. I guess I will be doing some soldering tomorrow. Thanks, Doug.
You're welcome, Alan. Good luck with your project.
I also own a Tele and could tell it was the mystery guitar. You could tell that amp was a match to the Tele. This latest project series is as good as it gets! It is a virtual look at an excellent repair/restore of an amazing tube amp. The owner will be very pleased, as usual. Can't wait for your next installment. Thankz
You're welcome, ATL, and thanks for the very nice comments. The owner has already signified his approval, so it looks like the project has been a success. The re-coning video should be out soon.....if I ever get the parts.
Honestly, I didn't care much for the bridge pickup and didn't like the neck pickup at all, but combined was sonic bliss, or at the very least a great usable sound to my ears. Never cared for the muddy combined sound on my Les Paul's. The Tele however was nice and clear and punchy as well. BTW, a great video as usual. Looking forward to the re-cone.
Thanks for your analysis, V.....glad you enjoyed the video.
As always, Rusty and Jack have produced a top notch video! Not too shabby yourself Uncle Doug! Thank you again for passing on your vast knowledge of these fine tube amps, it is a great learning experience.
You're welcome, Dave. I'm lucky to have two such energetic partners to do most of the work :)
Hey Uncle Doug thanks so much for sharing. If you only knew how many times I've said how I wish you were really my uncle Doug, because I would be a daily visit just wanting to learn all you have to offer. I'm just fascinated with your knowledge. Thanks again
You're welcome, Gil, and thanks for the very nice comments. Rusty and I are quite flattered :)
+Uncle Doug you're very welcome.
Thoroughly enjoyed watching this three-part video. Helpful clarification of the early tweed amps, and the input resistor modification is cleaver.
I'm glad the video was helpful, PW :)
Jack is a beautiful cat. His fur glows
Agreed, Monty. He's a special kitty :)
Another great series, a tip of the hat to our Texas Troubadours , Rusty, Jack & Uncle Doug! Bravo!
Thanks so much, Tim. We doff our sombreros to you too :)
Thanks Uncle Doug. i always enjoy your videos. i remember getting the chance to record with a '58 Deluxe. i'm more of a bassist than a guitarist, but i can tell you that my 80s Squier Telecaster never sounded better.
You're welcome, Alec. Somehow, the tweed amps just seem to go well with single-coils.....particularly the Telecaster.
You're so minimalist with these equipments. That's awesome😺
Thanks, Humberto.
+Uncle Doug just to not forget :D Is really very good to listen you testing your equipment🙌🙌🙌
I do, Humberto.....I promise :)
I just want to thank you for your expertise and taking valuable time for these wonderful and educating videos. I am semi retired at 65 and have time for learning electronics which I was always interested in. I have been repairing old tube radios and cant wait to build one of your amps. This is exactly what I was looking for. You have a knack for explaining and thank you again for sharing your knowledge. Love the humor with the pets. Please keep doing these. thanks Terry
You're welcome, Terry. I'm a few years older and find this to be a wonderful, rewarding hobby. Best of luck with your future projects.
thanks for another great video.a very sympathetic repair and a good tip about not over tightening the speaker. regards to rusty and jack.
You're welcome, Martin. I appreciate your analysis of the video. Rusty and Jack say "Hi" :)
Hey Uncle Doug, this video series really helped me out in building my own 5f11 vibrolux kit. I paused the video at strategic points and tried to copy Lupe's neat and tidy wiring as close as possible. The amp turned out great. Thanks for your generosity in sharing your tube amp knowledge in layman's terms on so many occasions.
You're welcome, Kevin, and congratulations on the successful completion of your project :)
Awesome videos, Uncle Doug ! I've just found your YT channel on my recommended list, and watched almost everything by now. I've worked 3 years on a local workshop here in São Paulo, Brazil building mainly Fender Tweed era replicas, but it has been a while since I'm "retired" of working in electronics (it gave me a huge problem that causes me terrible back pain) but sometimes I mess around with it as a hobby. Wish I've had known your channel back then, it would be very helpful at that time. I'm writing in this specific video because I've built for my personal use a Vibrolux 5F11 replica, and it works like a charm, but I've never noticed that flaw on the input scheme ! So, thank you very much for pointing that so I can add the 100k resistor in the input just as you did and save myself from some future headache !
Cheers for you, Rusty and Jack !
You're welcome, RK. Thanks for your input :)
It never ceases to amaze me how long a new speaker takes to break in. I broke in 4 Celestion Greenbacks ( Real ones, Heritage G12H made in England) in a Marshall 4x12 played regularly with a JTM45. I got a price on 5, and put one in a 74 Deluxe Reverb. 4 years later, the Deluxe Reverb became my number 1, after hardly being played with the new speaker. I swapped out the DR speaker with one from the 4x12 and the difference was unbelievable. The Moral of the story is never judge a speaker before it is broken in, which is going to take at least a year I reckon.
I agree, Paul. I will add that this Special Issue speaker, out of the box, is a lot closer to being broken in that a plain P10R. The plain one tends to be rather harsh and brittle.....and doesn't improve all that much with use.
Great for showing us these important modifications. Again i learned a lot. thx Uncle Doug!
You're welcome, Stefan :)
Thanks for the reply, Doug! I kinda guessed at Fender, not because of the sound, but because of the amp! My Fender Strat sounds a bit different, so again I thought 'maybe a Tele'! Keep these shows coming, I really enjoy listening to you explaining things! Have a good Sunday! Ben (Eccles Radio U.K.) here on the internet!
You're welcome, Ben, and thanks for your nice comments :)
This series just perfect :)))) Real pleasure to watch and listen. Thank You!
You're welcome, BMR. Thanks for your nice comments :)
Great series, thanks Dough! What a jewel of an amp.
You're welcome, Murrat......glad you liked it :)
I Like the Idea you are giving back the old parts so that the person can have a option. I am fooling around with a 61 Princeton amp and one of the resistors in the bias circuit looks burnt. I am going to take another peek at this video when I address the problem. Great Info Doug Thanks c];-D
You want to keep them working with minimal alteration, AL, and retaining the old (defective) parts with a vintage amp reduces the harm when repairs are unavoidable.
Uncle Doug, GREAT series here and quite helpful to me personally, I have a 1956 Vibrolux with "Lily" on masking tape in there, completely original except for me switching out the diode and adding the 100k resistor to ground in the input section. Alas I was unable to turn up a pic of Lily. THANKS for all you do!
Thanks, LA. You're welcome. Good luck in your search for "Lily".
I just want to say that you have been a HUGE help to me with your videos, I have learned so much over the last year or so watching you teach. I have a band with my wife named Adrianna Marie and her Groovecutters, very 40sish blues music. I would like to send you a CD of our material. If you want one please send me you mailing address to lajones@lajones.com. Thanks again, I look forward to more learning from you!
LA Jones
Thanks for the offer, LA. I will send you a mailing address.
Hi Uncle Doug & Family, Very nice resto-mod on the '57. You truly are the master! Learning a lot, way more to go. It sounds fantastic, I'm sure the owner will be quite pleased. Wishing you and yours all the best, take care, C.
Thanks, Cass. We appreciate your kind words.
Bravo!! Thanks so much for all of your time and effort in making these videos. They are greatly appreciated and a wonderful learning tool!
You're welcome, FS. Thanks for your very kind words :)
"...like a dog passing a peach pit." I had to pause the video because I was laughing so hard. Totally been there, done that.
It's an old expression that always makes me chuckle at the image it creates in my mind......glad you share my (warped?) sense of humor :)
Very nice job on beautiful amp Doug. I really appreciate the effort you make to produce these informative vids.
Thanks, HT. Rusty and I appreciate the kind words.
Thanks Doug. Both educational and entertaining!
You're welcome, Shaun.
"like a dog passing a peach pit..." Ha! The amp sounds sweet!
Thanks, T1.....Glad you enjoyed the analogy :)
that made me laugh out loud. Love your phrases, Uncle Doug!
Hi Doug. Fantastic job on the Fender Amp ! I hate to see the end of this series. What are the odds that, Jack and Molly have the same small tuff's of whit hair on their neck and belly ?. Amazing. Back to the Amp it's sounds and looks great ! Bravo Doug !. The Desert part in your other video was awesome to say the least. I don't comment every time has I figure you are busy and I do it out of respect,not because I am to busy or lazy. Just know I appreciate each and every video from you.
All my very best to you and yours
Bobby Molly and my wife
Thanks so much, Bobby. Rusty, Jack, and I really appreciate your kind comments and are glad you like the amp. It's always good to hear from you :)
When it comes to changing parts or making circuit alterations to an amp I really like your approach. It is thought through and done so carefully that, if desired, the amp could be returned to exactly how it was when you received it (I'm not advocating you blow the voice coil out). I believe Lupe would be very pleased to see your work and Leo would give a thumbs up to your circuit corrections. The tremolo does lack depth though, not in the same league as Uncle Doug's Tremoverb. I have tried watching videos by other amp repairers but for the most part have given up in frustration. The subject is interesting but they either swish up and down the amp like the camera is a spray gun or they go in and replace more components than is reasonably necessary. They should watch how you do it. Hope the re-coning parts arrive soon so you can make yet another video for us to enjoy. Then all we need is someone who would like you to "Take a look at his 5E9-A Tremolux......". All the best, Jeff.
Thanks so much for your very nice comments, Jeff. Rusty and I are proud of our work and really appreciate it when others are too. I have my fingers crossed.....both for the arrival of the re-coning supplies, and for someone to send a Tremolux for service :)
When I worked at Ernie Ball Music Mann years ago, a lot of Fender and Music Mann Amplifier history went to the land fill. Wish I did some dumpster diving.
Too bad we do not make tubes in this country anymore. There is still a need for tubes (valves) in audio, and ham radio applications.
Nice views of desert. Flew over many time while flight training at ELP and LRU.
I would love to have hijacked a few of those trucks headed for the dump :) Just about all of our manufacturing has been sent overseas, so I guess it's no wonder that vacuum tubes went there too. The desert you flew over is only 30 to 40 miles to the east of where the video was made.
Very interesting Uncle Doug.
Thanks, Rick.
OK, the mystery guitar was an early Telecaster, with that crazy treble dump on the neck pickup that nobody ever used. Leo got so much right that he can be excused the odd blip. He changed guitar playing for ever, and couldn't even play himself. Thank you Leo. Thanks Lupe, and a special round of applause to Rusty for his, (literally), boundless enthusiasm. Sadly missed. Oh, and to our favourite uncle, natch. Hogwarts' finest alumnus. Thank you all...
You are correct, Bill. It was a '52 Reissue with the old-fashioned wiring intact. Thanks for all your very nice comments.
You are most welcome, sir. Your videos have been a much appreciated distraction in these 'strange times'. I'm even in danger of learning something about these dark arts. (I thought it was a '51, but hey... Close gets no cigar)... Long may you continue to edutain us and restore all things electronic and feline to fine fettle.
Uncle Doug, thanks for another enjoyable video, the amp sounds amazing and I can't wait for the re-cone-ing video. Always have been interested in that actually. Buddy
You're welcome, Buddy.....glad you enjoyed it. If I ever get the re-coning parts, I will finish the video and post it......so stay tuned :)
Finally catching up! This is great. I will probably build a clone of this to donate to a fundraiser this winter (I built a 5C1-clone in a 5F1-style cabinet, complete with shellac'd-by-me tweed, least year for the same fundraiser). FWIW, I think this amp has the BEST tremolo! I like it on the subtle side. Reverb, on the other hand... that s**t need to be swampy :-)
Kudos, Doug! And keep 'em coming!
Thanks, Jason. It's great to hear from you. Rusty and I applaud your generous contribution to charity.....very commendable. We promise lots of new videos once some chores and other hobbies are dealt with.
You have been a fantastic teacher! I put into practice a lot of the techniques I learned from watching your videos.
That's great to hear, Jason. We're glad the videos are helpful.
Great series very informative and entertaining wouldn't expect less from You, Rusty and Jack. I'm looking forward to the speaker rebuild I hope you put it in a cab so we can hear it. Thanks for your efforts you really help us amateurs :]
You're welcome, Mike. The re-coning video is uploading as we speak. The testing is done without a cabinet, but I think you'll agree that it is adequate.
Good likeness of Jack! The neck pup on the mystery guitar has me completely baffled.
Thanks, Greg. The guitar is a '52 Fender Telecaster re-issue which has the original tone cap for the neck pickup.....making the tone a bit muddy. Newer Tele's have a different tone cap for this pickup.
That tone is to die for Doug! Lovely work, I'm guessing that this is one amp you'll be sad to see go!
Thanks so much, MG. Yes, I have grown attached to it :)
Fantástico....suena excelente!!! Gran trabajo Uncle Doug!! !!!
Gracias, Diego. Rusty y yo realmente apreciamos sus amables palabras. Gracias por mirar nuestro video.
Great video as alway Doug as I am an Ampliholic and a Teleholic I was onto your mystery guitar straight away that muddiness at the neck is a dead giveaway, easily adjusted with the right PIO cap, one of the reasons Fender supply a spare with the 52 reissue I think!
Thanks, Steve, and you're right about the Telecaster......it is a '52 reissue with the original cap in place. You do know your Tele's :)
yep spot on Doug I have a 52 reissue, a 52 Hot Rod and a Cabronita, plus I have fabricated a couple of partscasters for friends, I just think they are the perfect working musicians guitar :)
Indeed, they are compact, light, versatile, and sound great.....what more could you ask for ??? Thanks for the input, Steve :)
The schematic marking with "+" at the selenium rectifier's cathode (6:45) reflects the typical marking seen on the part itself. I suppose the reason is that positive DC voltage will appear on that terminal.
You could be right, Martin, but for some reason, Fender also mislabels the diodes in their non-selenium rectifier amp circuits. Most strange :)
Not really, I think they were just following the established practice. You still see that today in silicon bridge rectifier packages that have + and - marked at the DC outputs.
I'm not talking about selenium or bridge rectifiers, I'm talking about simple diodes. Fender labels diodes with the banded, cathode end + and the anode end -. In my experience, this is not established practice.
I understand, what I mean to say is that they were following the practice established for the selenium rectifiers they had been using.
Very informative, Thanks Uncle Doug ☺
You're welcome, Auntie J :)
Hi Uncle Doug, Rusty and Jack!!!
Whassssssup, Joe ??
great job! Amazing work on the control panel. thanks and good luck with the recone kit!
Thanks, Dave. You're welcome. Hopefully, the re-coning supplies will arrive before I am too old and senile to install them :)
thanks a lot for the video Doug , Nice sounding amp, crisp and warm too dependent on pickups, very expressive.
Thanks, Colin. I was worried that the excellent tone might not survive my primitive recording process, but it came through about 80% intact. In person, this little gem sounds even better....especially with single coil pickups.
love that speaker bolt trick!
Glad you liked it, Neale. Rusty sends his regards to the fine hound in your icon photo.
man what a sweet little amp!
Thanks, Steve :)
Sounds and looks amazing! Great videos!
Thanks, Sim :)
Hard to beat a tele and a fender amp, and don't forget the strat!!!!!. Give me a tele a strat and a les paul jr. and I am in heaven.
Well said, WN :)
The only problem with having those 3 is choosing which one not to bring
Very informative video.
Thanks, Andy :)
By the way, enjoyed watching the three part videos of you working on this nice sounding amp.
That's good to hear, Simon. Thanks.
it absolutely sounds amazing and i know what you mean about the imput Jack's, and the atom sprage capasitors ar one of the best I think. great job sounds good keep it up
Thanks so much, Jason. Glad you like the video and the amp :)
Congratulations !! The amp is sounding amazing. On the other hand i think Jack´s tubes need some Bias adjustment.
Thanks, Joao. Jack's tubes tend to be a little under-biased :)
Thanks for the informative and entertaining videoes,Doug. Maybe you could pound out some tunes out in the desert on one of your favourite amps sometime!
You're welcome, Arthur. I'll keep that in mind for my next trip :)
Amazing work, as always! Sounds great and looks great! I'm gonna guess that was a tele the second time around? Thanks for all the hard work you put into your channel and all of your projects!
You're welcome, Michael, and thanks for your very nice comments. Yes, it was a '52 Telecaster reissue.
Man, that would have been a funny mistake if I couldn't guess it, as I own a 52 reissue. haha
Indeed.....does your neck pickup sound as "mellow" as mine ?
"shakin' like a dog passin' a peach pit"
thank you sir.
You're welcome, Jon. You must admit, the saying does conjure up a very vivid, yet accurate, image :)
perhaps this explains why Rusty doesn't seem to be so eager to participate - is there a peach tree nearby? he does look somewhat 'full'.
Rusty swore off peaches many years ago, for reasons best left to the imagination. He still shakes a bit whenever he hears about or sees peaches.
Uncle Doug, I searched your videos but could not find one that covers my questions completely. I have a 1959 vintage Tweed Bassman that is blowing fuses. In the past (two other times in my 1960 Bassman) it was the GZ34 rectifier (expensive NOS Mullard) tube that was going bad. I have a unique filtering setup as per Gerald Weber which is way higher that the max 60uF spec of the GZ34. But, Gerald does other things to minimize the strain on the rectifier. I have not had many problems but I suspect it is the extra load on the tube that causes them to eventually wear out. I have thought about doing two new mods when I get my new modern JJ GZ34 and diodes. I was thinking of replacing the selenium rectifier with a IN4007 diode and was told I don't need to put a resistor in series with it. Some circuits may require the resistor. I have an adjustable bias installed so I am assuming I can just put the diode in place of the selenium rectifier and be done with it. What do you think? Another mod I was thinking of doing was adding two IN5408 (3A) diodes in line with the 325VAC coming from the PT to the rectifier socket (pins #4 & 6). I was told this can take some of the stress off of the tube by "pre-rectifying" the AC voltage. What do you think about that? I've found schematics online that show using pins 5 & 7 as solder points and then bridging the diodes from pins 5 to 4 and 7 to 6. Thanks for your help.
It appears that the modifications you installed have unpleasant side effects. Personally, I would return the amp to its original configuration and enjoy it as it was intended to be. Excessive filter capacitance causes way more harm than good, as you have discovered. Yes, you can replace the selenium rectifier with a diode....it's a common improvement.....but you will then have to adjust the output tube bias due to the probable increase in -DC voltage to the grids. Adding the diodes to the rectifier pins is another fairly common alteration, but it does not reduce the stress on the rectifier, since the stress is a result of excess initial current flow (due to excessive filter capacitance) not the "stress" of rectification.
@@UncleDoug Yes, the higher filtering is debatable. I have not had any real issues with it because Gerald bypasses the standby switch and pre-charges the main filter caps while the amp is still in standby mode. He says that reduces the surge on the GZ34 but still, I have blown three (maybe) now over a 10 year period so it is tolerable. But, I may just go with the blackface filtering and put two 100uF/350V caps in series for 50uF/700V. I think I have a couple of 100uF/350V caps. I read one place where the resistor in series with the IN4007 on the bias supply is necessary to reduce available surge current but I think that is a different situation in the B+ side of the circuit and not the bias supply side. What is the advantage of adding the diodes on the rectifier socket then? I also read that the selenium rectifiers can start blowing fuses too when they age. Mine are all the original seleniums. PS. The high filtering is only necessary if you play the amp very loud which is supposed to keep the notes in tune according to tests done by Gerald many many years ago. I do play my amps loud but don't gig with them anymore so I could go back to lower uF.
@@millstap Sadly, many modifications are done simply for the purpose of changing something. If Fender really thought that larger filter caps would provide noticeably better tone, they would have installed them, even if it cost a few more cents. This explains the diodes on the rectifier pins: dynacotubeaudio.forumotion.com/t1006-tube-rectifier-yellow-sheet-diode-mod
@@UncleDoug Thanks for the help Doug. Fender did feel the need to change the filtering in the Bassman in the '59 Reissue so they must have figured out the 40uF/600V was inadequate. They beefed up the voltage rating in the AB763 circuit in the '60's to 35uF/700V. But, in the new '59 Reissue Bassman they went with two 100uF/350V caps in series for 50uF/700V. I will go with the Reissue specs and see what I think. I did see that article about the rectifier diodes so I'm glad to know you are referencing the same forum thread.
@@millstap You're welcome, M. I too tend to favor the reissue specs, simply because they (should) reflect improvements noted over time.
hey doug great stuff told my friend at gc to look you up. he works there super nice kid told him about. youre scratch videos
Thanks, James.....we appreciate any publicity :)
Hi Uncle Doug,
Bravo! Excellent final episode to the series! Could that anomaly in the first input jack have caused the speaker to blow?
Folks as I stated before don't forget to "like" this video by clicking once on the thumbs up image at the bottom right of the video screen. It is the only way to thank "Uncle" and his buddies, Jack and Rusty, for this complimentary and pleasurable viewing fun, entertainment and especially the educational value so skillfully presented within the matrix of the production!
Many thanks of appreciation! I just wish there were other ways to show my thankfulness?
Kind Regards,
Steve
You're welcome, Steve, and thanks for all your very nice comments and "thumbs up" support. I have no doubt that if you were operating the amp at relatively high volume on Input 2 or 3 and then switched to Input 1 the speaker would be damaged. I'm not sure if it would have been blown to pieces like it was, but it would most likely be blown. I have no idea how this input design was ever acceptable. Re the "thankfulness" please see the note at the end of the video notice sent to subscribers re Patreon. This channel has become a "full-time job", so Rusty and I decided to follow the advice of some viewers and allow people to contribute if they wish to show their support for our efforts......and provide Rusty with some higher-grade, lower-calorie food :) Our Patreon site is "Uncle Doug and Rusty". Thanks again :)
Hi Doug!
Great feed money on the way shortly.
Kind Regards,
Steve
Thanks, Steve :)
Hey Doug, great video as always; your videos are truly an education. However, I'm not so sure about your analysis of the input circuit starting at 12:39. I agree that when you connect to input one only there is no grid leak resistor (except that of course the guitar itself will act as a the grid leak resistance). When you connect to input 1 you get the full guitar output voltage to the grid. When you connect to input 2 you get 2/3 guitar voltage to grid and when you connect to input 3 you get 1/3 guitar voltage to grid. In the case of input 2 you get 68k to ground and in the case of input 3 you get 34k to ground (ignoring the resistance of the guitar). This is all assuming you only connect one guitar to the amp at one time.
Thanks, Dave. I will agree that, when plugged in, the guitar volume control could provide the ground reference needed for tube bias.....but I stand by my analysis of the input impedance. I believe you're ignoring the collective effect of all 3 grid blocker resistors. In actual testing, attaching an ohmmeter to each (ungrounded) input leaf will yield about 100K impedance to ground for all three inputs (including No. 1, now that the 100K resistor was added). To me, an infinite input impedance is simply not practical or usable. I added a note to the video about the guitar volume control providing bias reference, and explaining that the impedance for Input 1 can be tailored to your needs simply by adding a higher or lower value resistor. Thanks again for your input.
OK, we seem to be reading the schematic differently. I have drawn out my interpretation and posted it here i63.tinypic.com/sm3o04.jpg It seems to me there is a potential divider effect for inputs 2 and 3. Please do take a look and let me know your thoughts. By the way, I wasn't defending the lack of grid leak resistor on input 1, just making an observation. Regards.
Thanks for your careful analysis, Dave. I agree that if a guitar is connected to the amp, it, in effect, becomes part of the circuit and provides the impedance to ground missing in the amp circuit. My analysis was purely of the amp circuit itself.
I repeated my impedance (signal to ground) measurement of the 3 input jacks with a "mock guitar" (230K volume pot, signal to ground) plugged into each jack. Results with the added 100K resistor: 1 = 69K, 2 = 74K, 3 = 74K. Results without the added 100K resistor: 1 = 230K, 2 = 74K, 3 = 74K. Results with an added 220K (instead of 100K) resistor: 1 = 111K, 2 = 74K, 3 = 74K. As a result of these measurements, I'm going to change the 100K added resistor to 220K, giving the 1st input jack a reasonable amount of higher gain than 2 and 3.
OK, thanks for your reply. Now I'm looking forward to the re-coning video.
You're welcome, Dave. I got the supplies yesterday afternoon and, hopefully, the video will be out soon.
I can't believe how clean the amp was inside.
Nor could I, Tele. It was a gem :)
Great Job Guys!
Thanks, W4 :)
The amplifier has a great tone! But, I can hear the delay in the tremolo. That has to be uncomfortable for players that are used to the quick response and thick tremolo. Again, it saved Fender from using an extra tube and components. That input circuit design was a bad move on Fender's part, but is easily modifiable...Changing the resistor for the first input jack is a mod I always make. That Telecaster sound is recognizable from New Jersey :) Even tough I'm not a guitar player, each guitar has it's own distinct sound that can be heard instantly. My instrument is the Hammond B3 Organ (jazz organist) it's hard to do the real world tone test on an amp for me in the shop. I usually ask the customer to bring his ax for the final listening test. Excellent 3 part video. :)
Thanks so much, Frank. We always appreciate your knowledgeable input. Yes indeed, it's a '52 Telecaster reissue.
Doug, thought i might mention the sound is a little late. I do enjoy your videos... Thanks!!
I noticed that, especially with the hum testing of the three input jacks. I have no idea why. You're welcome.....glad you enjoyed the video :)
lovely amp. I love tweeds. Does anyone know why fender didn't replace tube rectifiers in all thier amps with solid state diodes? Tube rectifiers survived in Deluxe Reverbs and some Pro Reverbs even through the CBS cost cutting...I can't help wondering why. Especially as GZ34 tubes offer little if any sag.
Thanks, Paul. I think Fender was rather conservative about radical changes and, let's face it, almost all low to medium output amps in the 50's and 60's were tube rectified. It may be "old fashioned" but it was part of the tone that people sought.
Very interesting and instructive, as usual, Doug. Keep 'em comin'!
Thanks, Ben :)
I have a 1960 Vibrrolux and would love to have a schematic for it. since it is all original. Could you send me a link to where i could download the schematic at?
Try EL34 World, Rick. They have a great library of schematics.
Uncle Doug you are such a good teacher and might even have a mild case of geniusitis. Your delivery is such that most, that is ones with half a brain, can understand and more importantly in an inviting way captures my interest. I love the breaks, or comedic relief, with Rusty and Jack. I am guessing that Rusty may no longer be with us and that would be a sad thing if true. I am a true-blue pet lover (who happens to struggle a bit with depression) and couldn't get by without my golden doodle (Jarvis). I spend a lot of my extra time watching your videos and I can't wait for your next series. If I were closer I would bug you to let me come apprentice at your side because your teaching style meshes very well with my learning style. Anyway... another great mini series by you and your comrades. Hope you are enjoying your sabbatical, lol.
Thanks so much for your many nice comments, Scott. We are indeed enjoying our break from video production, but do intend to return when a great topic and sufficient inspiration are discovered.
Your welcome UD. FYI, my first project is a 1965 Kalamazoo model 2 that I bought very cheap. It has a 1/2 12AX7 driving the tremolo. Pretty cool. It works but needs some love and thanks to you I feel confident enough to dive right into it.
Good luck with your project, Scott.
Telecaster!! Beautiful work, and a gorgeous sound. Subtle would be a good description of the tremolo. :)) A nice trick with the tubing on the studs. I think Jack was resting up from all the hard work filming and editing a great series. Thank you.
Andrew
Thanks so much, Andrew. Yes, indeed.....a '52 reissue in fact. Glad you liked the tubing idea.....I also use this on desert vehicles to keep them from disassembling themselves 20 miles out in the dunes. The tremolo is subtle, but it still trems its little heart out :) Jack is like an alligator sunning himself on a river bank.....just when you think he's either dead or asleep, he jumps up and runs around the house like a lunatic.....much to our amusement :) You're welcome.
I want a T Shirt that says "All I know about 'luxes I learned from Uncle Doug"
We've been considering getting some t-shirts made with a goofy Uncle Doug and Rusty logo, Lincoln. There are some Internet companies that will make, sell, and ship them. If I get a chance, I'll check into it.
+Uncle Doug i would buy it at the instant !=)
Thanks :) Your enthusiasm is contagious. I really need to do this.
Tone demo sounds real good with that new jensen. I hear smome old familiar guitar strains and riffs, but I can't place them anymore..too much water passed under the bridge as they say. First guitar must be a strat? drastic tone difference between neck and bridge on the second...definitely tele or at least some form of it.
First guitar had humbuckers, second was a '52 Tele re-issue, in which the neck switch position activates a tone-modifying cap to emphasize bass tones. This is how they were originally wired.
looks like Jack ain't having none of that! haha
He's too cool to play the fool :)
Hi Uncle Doug, I love watching these AWESOME video's, and have been
doing so for the last 6 months. I'm so impressed that I went and
purchased the guts of an old Thomas/Leslie organ that came equipped with
about 80% of what I need to build my own amp. My Traynor YGM-4 Studio
Mate (yes, I'm a Canuck from Montreal) is just too big to lug around, so "compact and portable" is the new mantra. This Vibrolux is the one I have my heart set on
building, the box is done, but after winning the staring contest with
the underside of the organ chassis, I discovered my power transformer
has only 2 ground leads and 8 others. Before I make a terrible
assumption, I want to check with you to see if it matters if I use
either of these ground leads to connect to the 10 K resistor before the
diode? As an aside, why do we feed back the output from the speaker
signal back into the second 12AX7 cathode? Thanks, Alf
Thanks for your nice comments, Alf. The two ground leads are probably the centertaps for the high-voltage and the 6.3VAC windings. Both must be grounded. I don't understand why you would want to connect either of them to a resistor or diode. The return to the cathode from the output is a negative feedback loop. I have posted a video that explains how it works. In general, it compresses the output signal, "cleans up" the signal, and reduces excessive volume.
Thanks for writing back, you're a pal. Upon closer examination of the
power transformer and a review of your video on how to identify
transformer leads, I discovered I'm missing that high voltage bias
supply, so I'm going back to the 5E3 Fender Deluxe and I'll see if I can
find a mod to add a tremolo circuit. Give Rusty a nice pat for me.
You can create a bias supply from the high voltage winding. Look at how Fender does it in the AA764 Princeton Reverb. Rusty says "Thanks".
Hi Uncle Doug, I watched that video you did on the single variable trim
pot you insert on the Princeton Reverb with the diode to negative bias
both grids and it really enlightened me, it assumes both tubes are
matched. I've decided after watching the two part bias videos again
that I'd prefer to have two trim pots to cathode bias each of the two
6V6 output tubes, the design is simpler. The Tremolux uses this
approach and I like the sound of that amp with a bit more of it's mid to
bass tone and over-driven blues tone, so I'm going to proceed to clone
that one and let you know how it goes. If you ever get up our way to a
Jazz Festival, or any summer festival, the beer and popcorn are on me.
You're the master.
Good luck with your project, Alf. Let us know how it turns out. Also, you better watch what you're offering.....Rusty has been known to consume prodigious amounts of beer and popcorn, so you'd better have a healthy limit on your credit card :)
That amp sounded sweet, Jazzmaster
Close, Shane. It was a '52 Reissue Telecaster. Thanks :)
Howdy Uncle Doug. I know I'm about 6 years late with this comment, but I wanted to point out that I know a number of techs who, like I, have had BAD experiences with Sprague Atom electrolytic caps. They just don't hold up very well over time in my opinion. I know there's a great deal of hype about their supposed incredible quality, but I'd argue it's really just hype. I had 5 in an old Vibrolux Reverb dated from 29th week of 2010. This amp hasn't been used for more than a total of 20 hours in the last 11+ years since those caps were made and I had one fail this week (Feb 2022). The amp has lived in dry, sunny-southern California all this time and not been exposed to cold or humidity.
I decided to cut open the 16uF Atom that just failed and I can tell you that inside, the dielectric is rather puny when compared to the blue cover; it was about 1/4" shorter and maybe 3/5ths the diameter. Not nearly as impressive is the big blue exterior shell!
I simply don't use Sprague Atoms anymore. I've been using MIEC caps with much better luck, FWIW.
I share your opinion, Leon, and have ceased to use Sprague Atoms, largely due to their unreasonably high price for rather dubious quality. My go-to caps now are F&T's.
@@UncleDoug Yeah, F&Ts are excellent caps, IME!
This trem may not have the awesome psychadelic wobble we're used to, but at moderate levels the delayed onset makes it far more musical and doesn't randomly remove attack.
Thanks for your input, OW.
This magic moment so different a different and so newwwww .hit it.teenager in love.kinks sound nice.
Thanks, Stephen....glad you liked it :)
I put the nuts on with a deep socket, alone with minimal force, so probably about the same as finger tight. I agree though, a speaker doesn't need lotsa torque to be held in place securely.
Love the way it sounds. Really like the idea of a high and low gain input. On such an otherwise simple amp, you can really change the way it responds.
I agree with all you say, Lincoln. Hopefully others will heed our advice. Over the years, I have seen a few speakers permanently damaged by over-tightening. I'm glad you like the tone and hi/low inputs.
Great video as usual, wow were you ever right about the tremolo being "barely there" as compare to others you have done. I was going to guess Stratorcaster until you played the neck pickup then I figured it was probably a Telecaster. Once again Jack was brilliant demonstrating his dominance, and you were just as brilliant with your amplifier prowess.
Thanks so much, Mark. You're right about the tremolo and Telecaster.....and Jack. Three out of three ain't bad :)
Is the mystery guitar a telecaster? Pretty good twang there.
Yes, that bridge pickup is hard to miss :)
how old is the tele? does it have the old circuitry where you can only blend in the neck pup full out but if you move the pup selector to neck only it is the tone fully off and the fake base sound? i am thinking early esquire or nocaster
It's a '52 re-issue with the old circuitry intact. I may change it in the future.
I was amazed at how DULL the neck pickup sounded!
Diode +/- labeling conundrum. If memory serves, if the DC voltage is measured across the diode it will read as the same polarity that is marked on the schematic. For factory checks or for troubleshooting that labeling might be helpful. Makes sense because the meter will be displaying the voltage drop across the high resistance of the diode when it is not conducting.
Perhaps you're right, Tony. It may be beneficial for troubleshooting.
Hi Doug Steve for Aus again thanks for this video I had a Harvard that I was working on today guess what? same issue that pesky Diode its the same mistake on the schematic again got it right paralleled the 56k with the correct resistor hey presto -27 volts and perfect tone. BTW Jacks Australian Double known around these parts as the Black Flash is doing Just fine LOL
You're welcome, Steve. We're glad you were able to solve your diode problems. Rusty send regards to his mate, Black Flash, and invites him to join us for a nice, cold Foster's whenever he's in the neighborhood :)
Your welcome Sir !!!
Doug - You got me thinking about the impedance mismatch of input 1. I built a 5E3 and would like to fix this issue if it is present. I'm a little confused by it as when you look at the 5E3 schematic, are the arrows representing the grounds of the jacks? I see what you mean in the video looking at the vibrolux schematic but the 5E3 schematic has me confused.
The arrows are not ground. They show where contact occurs between the leaves of the input jacks. The 5E3 does not have the impedance issue seen in the Vibrolux. Both jacks have a 1 Meg ground.
@@UncleDoug Thank you Doug!
Great job! Sounding the business now. I wonder how fender approached the inputs in reissues. That painting of Jack at the end was fantastic, another string to your bow? Hoping today finds you well. Keep it between the ditches!
Thanks so much, PJ. They redesigned the input circuit for the brownface and blackface amps. I'm glad you like the painting.....my wife is the artiste in our family :) All is going quite well, especially with nice viewers like you. We will :)
Have you used locktite on the speaker mounting bolts?
I have, as well as lock washers and short pieces of tight-fitting rubber hose to keep the nuts from loosening.
Hallo
I enjoy the video tanks
I have a question for you uncle dog
do you have a example of a 8 ohm dummy load that i can use for testing a amp
Bertus
You're welcome, Bertus. My 8 Ohm DL appears in the video about how to measure amplifier power output. You can buy them on Ebay at a very reasonable price.
Mystery guitar sounds like a '52 Telecaster, I checked out the wiring of my 2014 Fender Mexican Telecaster, and it looks to be wired to Fender's 1966 Telecaster specs where the pickup selector is wired to allow the neck, neck plus bridge, or bridge pickup selections, with a master volume and tone control, tone cap is a .05uF ceramic, but I might swap it out for a .05uF Orange Drop or some other cap at a later date.
Yes, a reissue with the original tone circuit. Good guess, Simon.
Would input 1 be considered a hi gain "channel' for lower output pickups or some other style of lo gain device? and done
on purpose?
Probably so, SC, but to a rather extreme degree for modern instruments, especially with humbuckers. My modification has changed it into a "moderately higher gain" input.
Well, I've never understood why Fender would have 3 inputs shared by the same channel preamp input.
One guitar input for normal output single coils or humbuckers for this kind of amp. For the second (say the rhythmn guitar, if one had no choice, to plug in their guitar at a HS dance, would be about all this little amp could handle. Three guitars? and the last one plugged into the high gain input..no wonder the speaker
cone got shredded..i would imagine quite a feedback howl coming out this little amp.
Also, were Humbuckers even available at the time the amp was designed or built around 1957 ?
Gibson just started production of the PAF humbucker sometime in 1956. Was Fender even concerned about this? Gibson did have their P90 single coil on their products well before 1957 though.
Interesting if one go back to discuss what they were thinking using 3 inputs on a 17-18 watt amp? with no independent channel volume control for each input...very strange design coming from Fender and we thank
you for pointing out this anomaly Uncle Doug.
I just can't see 3 guitars plugged into this amp and sharing the same input preamp. One guitar would probably be the norm. 3 guitars would be an invitation to disaster for this little amp.
It would be like watching an episode of "The View" on television.....with everyone trying to out-yell each other. Utter pandemonium. I don't understand the multiple inputs either....unless maybe one for guitar, one for harmonica, and one for singing????
That might have been the intent. However, having three different instruments with different outputs..
mic/harmonic/guitar would have been quite a juggling act with just one preamp and one volume control.
Now if the three different input sources actually went through a mixer, each with it's own gain circuit and
volume control, and then three outputs..maybe..
but then with one mixed output, why would you even need 3 inputs of the same impedance (practically), going to the first preamp tube.. One instrument input would easily over power the other two in volume.
this is bizarre thinking even from a company renowned for it's practical amp designs, like Fender.
I agree, SC. Later on, they offered two separate channels, generally clean and with effects, that were more independently adjustable.
Very nice repair and alteration on this girl I would hate to think what its resale is ,the new reissues are 2 grand and more wowsa ,guess should have gone with a fender instead of gibson lol
Thanks, Joe. Yes, I think Fender would have been a better investment.
A Weber 10F150 might have been a better speaker for this guy providing a bit better bottom end. Ahh. A little, "Night Train" going down!
I knew right away that the second guitar was probably a 50's or low to mid 60's Tele. I have a '67 Tele (which I bought brand new) that was one of the last to have Leo's "dark circuit" in the neck position. This was supposedly to allow the guitar to sound like a bass if needed. I have so far resisted the urge to mod it from the original design.
Yes, it was a '52 reissue. I have no idea why Leo would want a Telecaster to sound like a bass guitar.....but so far I've left my "dark circuit" intact too.
I have a Telecaster, my first thought was the Tele. I wonder what a Duo Sonic would like through that amp? Very nice Amp and video!
Thanks, Jack :)
I Think Jack likes to relax, after such a big meal.
Like a hyperactive child, he has periods of wildly running around the house.....followed by long naps. Actually, not a bad lifestyle, other than the wild running :)
Uncle Doug
The life of a King.
Indeed :)
Hello Dear Uncle Douge and Rusty, first of all thanks for share your know how with us. I'm assembling my first tube amp (Rick-Tone Jupter) and it's not easy to find some parts like axial capacitors and tube valves. May you suggest us a store (web site) where we can buy these parts (specially axial capacitors)?
You're welcome, Thiago. We're glad the videos are helpful. I order all of my electronic parts (except transformers) from Antique Electronic Supply in Tempe, AZ They have a nice website that you can order from online.
Doug - I found a Fender Bassman ( stamped 1971 inside the chassis) and I am having trouble finding the right circuit. The serial is a61xxx so I know its either Ab165 or aa270 perhaps. Any easy way to tell which one it is ? Someone replaced the EL caps with very wrong values and I want to get her up and running again. Any help is completely appreciated. Ron
I assume there is no tube chart in the cabinet, Ron, because that is where the circuit is generally identified (not always accurately, however). My method for differentiating between different circuits is to download the schematics for the circuits the amp could possibly be, and then comparing the component values, rectifier choice, transformer ID numbers, etc. to determine which circuit it really is. In some cases, you may have a hybrid circuit, in which more than one schematic will apply, but generally, it is quite possible to nail down the circuit's identity by carefully comparing it to the schematics. Good luck.
Thank you so much Doug
You're welcome, Ron.
Uncle Doug h
looking forward to the re-coning video, always a bit of a dark art to me, and i always send away for speakers to be re-coned...tried it once many years ago and totally messed it up. never tried again, so be interested to know how you go about it.
I hope the video is helpful, Sparkey. I agree that any re-cone has some possibility of error (and wasted time and money), but with a speaker like this, it's definitely worth the risk.
Where do you typically buy the 5 X $$ electrolytic caps?
I got all my supplies from Antique Electronic Supply. The Sprague Atoms cost $12 apiece and the Chinese equivalents are about $3.50, so it's more like 3.5 x the price :)
Fortunately, there are now better, cheaper, and much smaller alternatives to those Atom caps.
Another great and informative video entry in the annals of tube amp cognizance...thanks again, Uncle Doug.
Not that it was necessary on this beauty, but when you need to clean the accumulated grime from tweed (and possibly from grill cloth), what's the best approach?
You're welcome, C7. I would leave a grill cloth alone.....unless it's simple cloth and you want to remove it from the cabinet and try washing it with Woolite. For the cabinet, a moist soapy cloth will remove most of the grime.....but don't overdo it or get it too wet.