1939 Rickenbacher Model 59 Lap Steel Amp Restoration
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- Опубліковано 1 жов 2024
- This video follows the step-by-step restoration of a 1939 Rickenbacher Model 59 Lab Steel Amplifier. The amp arrived in my shop in non-working order, with no available schematic, and an incorrect tube set. All steps of restoration are covered, including research, disassembly, circuit analysis and hand drawing of a schematic, explanation of the schematic, proper tube selection, circuit repair and testing, safety measures, tube testing, and final evaluation. I hope you enjoy it.
If you enjoy videos featuring vintage amplifiers, jukeboxes, and exotic electromechanical devices, please subscribe to my channel. You will gain immediate access to well over 100 videos and you will be notified each time a new video is posted. Thanks for watching !!
I had the 1938 guitar
just found your videos. They are timeless and so interessting. thanks. keep up your good work and please produce more videos.
Thanks so much, Jimmy. Will do :)
That amp was thinking "its been a long time since I played this song…Im back after a long lay off."
Greetings, HA. I really used to get that feeling whenever I finished restoring a jukebox and had it play its first record in many, many years. It's like it has come back to life after a long sleep.....completely rejuvenated.
As always, that was fun.
Thanks Doug,
Carl
You're welcome, Carl. Glad you liked it :)
Just found this one, the matched lap steel guitar played through the model 59 Amp: 1939 Rickenbacher Lap Steel Guitar w/Original Model 59 Amplifier
I watched the video and found it quite amusing. This is exactly how the unit was intended to be used.....and the volume was more than adequate. Thanks for posting, TC :)
You´re very welcome, Doug! Hoped that you finding this one interesting....:)
The old guy is pretty good. Sadly this type of performance will probably become a "lost art".
What a treasure!!! Thank you Uncle Doug for these wonderful videos! They are precious glances back in technical history. Keep up the good work!
You're welcome, PN. Thanks for your nice comments :)
In lieu of popcorn, I grabbed a bag of ........ uhhh ........ nevermind.
Nice to watch a tube amp veteran at work. A tube amp rookie like me really enjoys what I can learn. Now I need a tube tester, signal generator, and O-scope... I've been able to solve plenty of problems with a volt meter, and a good set of eyes and ears.
Fortunately for me, we have a tube amp guy within a reasonable distance who can solve the problems that I can't... and I get to read his honest and accurate notes when he's done.
Thanks so much, DK. It's good to hear that the videos are helpful. Good equipment is definitely an asset, as are a good set of eyes and ears. You're fortunate to have a competent, honest technical person nearby. From what I can gather from other viewers, your situation is all too uncommon. Best of luck with your continued interest and ability in tube amp repair.
WOW ... THAT THING SOUNDED REALLY GOOD ... HEY UNCLE DOUG ... GREAT WORK BUDDY ...))) ... I'M MAXIMUM ... I CHANGED MY NAME DUE TO A BUNCH STUPID THINGS ... GREAT STUFF ... THX AGAIN FOR YOUR WORK ... LEARNING ALLOT ... )))
You're welcome, TAT. We're glad the video was informative.
HAHAHA!!! At 2:20 you said "massive power transformer" and Rusty yelled from out side "How big is i?"
Greetings, Adam. No matter where Rusty is, he always appreciates a massive power transformer.....and who can blame him??
Hi Uncle Doug! You've just got to love these old amps and their scale of economy. Sometimes guffawed at, the engineers were pretty clever in using as few parts as possible!
Greetings, Ab. You're right, they were certainly able to accomplish quite a bit with minimal parts. Like the Model T....good, reliable transportation for $500. Nowadays, people are spoiled. The auto-adjusting rear view mirrors on my car probably cost more than $500 apiece....but it sure beats having to reach out a few inches to adjust them by hand :)))
I'm impressed with your dedication to our craft. I have to be honest. I would have walked away, with no schematic. Probably would have walked away anyway. You're an artist.
Thanks so much for the kind words, CH.
Great vid! Wow! Couldn't believe the soldering (???) on the cap PLUS the long lead left for extra sparking fun! LOL!Glad you could save another historical piece! Glad Rusty getting some R & R!
Thanks, Tim. It's "shocking" just how bad the previous work can be on some of these old amps....and it's a great feeling to return them to their former glory :) I got a postcard from Rusty. He's partying with his relatives on the Gold Coast in Queensland. No doubt they've lined up some poodle pole dancers :)))
I love Uncle Doug's
Sarcasm. Comical funny
Very good repairs on antique amplifiers very interesting knowledge to listen to and pick up on.
Thanks, Dwight.
Great video uncle doug really enjoyed it thank you for sharing it !!!! one time i saw a simmilar looking cabinet for sale in a second hand store and my eyes almost came out of their sockets it even had the similar handle to a gitar amp, however upon closer look i realized it was just an old portable heatter.....so disapointing
You're welcome, German. I too have gotten all excited when I found something that resembled an old amp.....only to be disappointed. Thanks for watching and for posting a great comment :)
i hear you i too love old vintage electronic gets my blood pumping look so sexy
love build valve gear
HI Doug ! Brilliant job sounds very nice too. Your video work is very clear all in focus. Just the job ! I do like your circuit diagrams, do you hand draw them ? Anyway off for some Bass practise now .Regards . I must have a look at your phase inversion videos . Thanks again.
Greetings and thanks, Dave. I recently upgraded to 720p High Definition after a viewer correctly suggested that I do so. In this case, the schematic had to be hand drawn because, to the best of my knowledge, no schematic (or any circuit information) was available. Please do watch more videos....I have posted over 100 and many cover basic technical topics.
At the end, The Ventures? Walk don't Run? I love The Ventures! My step mother had like 8 of their albums...which unbeknownst to me she sold at a yard sale for like a quarter each...I could have strangled her when I found out, lol. Great video! No Preamp, I didn't know that was possible, but I guess if you have enough gain it's okay. Thanks for yet another very informative video!
I drove my parents crazy with a Ventures album when I was a youngster. Surprisingly enough, my mother later confessed that she really liked the surf music, as well as Floyd Cramer albums......"Last Date". You're welcome, Jack.
First rate presentation.
It's got a growl. Don't you have a steel guitar ?
How about a harmonica !!
Would love to hear a few harmonica riffs here....
😊
Thanks, Paul. Sorry, no steel guitar or harmonica.
"Walk Don't Run '64" The Ventures. Nice video, Doug. Thanks.
+Wayne Bjorken You're welcome, Wayne. Glad you liked it :)
THIS WAS ANOTHER CLASSIC I THINK."HOW TUBE AMPS WORK " SHOULD BE REQUIRED VIEWING FOR ALL GUITARISTS!!! THANKS SO MUCH FOR ENLIGHTENING US.
Thanks so much, Bob. I'm really glad to hear that the videos are helpful. Nice comments like yours make it all worthwhile :)
Another great video, cheers Uncle Doug. As a fan of old pre World War II cinema/hifi equipment (Western Electric, Altec, etc), I agree that it is a blast finding these old amplifiers.
Thanks so much, Nath. I definitely share your interest in pre-war electronics. Glad the video was of interest :)
They must have pulled this amp out of a hair salon. the label must have read "Bride of Frankenstein" hair do. Doug thanks for bringing the amp back to it's original purpose. Take care.
You're welcome, Franky....it was a pleasure. The wiring was a little ratty, wasn't it ??? :)
that is an awesome little amp! i would think you could increase the gain by increasing the input impedance to ground w a 1M? or add a bypass cap to either (or both!) cathodes.
you could add a trim pot where the 20k tail resistor is and use it to balance between the tubes.
in my limited experience with 6N7's... yeah. theyre microphonic. work great in a head. not to great in a combo.
do this amp w/ a 12AX7, and your on to something...
Thanks for all the very helpful suggestions, Jim :)
That paint job gives me hints of the Fender's Antigua from 30 years later. Great stuff on paying attention and being careful.
Thanks, Stephane :)
An oldie but a goodie Uncle Doug!! Pre to your working on it I to conquer this is not one that the UL people(we all love so much)would approve of operating out doors in foul weather..👌☔️
Heck, they would probably certify it for use under water, as long as their fee was paid ;)
Very cool! Was wondering about rusty ? Thought maybe the fame turned him all " diva" on you . Great video look forward to more. :)
Greetings, Bryan, and thanks. He's attending a family reunion in Queensland, Australia, and couldn't participate in this production. Hopefully, he'll be home soon, tanned and rested, and ready for action :)
Once again a great video. Really liked the process you go through in troubleshooting. A good blend of knowledge and common sense approach. I hope to be that good someday but for now I'll watch and learn and muddle through.. By the way I hope you are training Rusty on your new camera.
Thanks so much, Gary. A viewer requested a step-by-step explanation of the repair process and I hope this video provided it. I'm still using the same camera, but have improved my format and uploading methods (as per the advice of a very helpful viewer) to enable 720p HD. Rusty is really attached to this camera and it would be too traumatic (for both of us) to try to get him to change :)
Excellent video once again. Thanks for not talking down to your viewers.
You really stuck your neck out on your call of the mounting screws.
You're welcome, Joram. Thanks for your nice comments :)
Neat old amp...Needs a rocker switch...I know they wanted original.
Thanks, Jammy.
Don't play the guitar but I'm quite interested in electronics and I enjoy watching you work on these vintage beauties! Keep up the good work! Greetings from Germany!
+J S We will, JS. Thanks so much for your nice comments :)
Cheeses, I bought a Magnatone 262a and a '67 Royal Reverb only to fall in live with the growl of this l'il fella. Shoot!
If I still had the Rickenbacker (it was a customer's amp), I would trade you for the Magnatone, KM :) I recently bought a really nice old Magnatone (with true Vibrato) and have become a big fan of the brand.
The first view of that amp looks like it was built into a picnic hamper, or a camp stove box.
I don't know what those waxed-paper capacitors are doing in the amplifier. I wouldn't trust them if there is any big potential difference across them.
I'd return all the old capacitors to the owner in case they have important evidence for when an amplifier was built.
I always return all the original parts with any vintage amp I work on, NJ.
10:38. Ahh... Now I see why your adamant on doing soldering jobs properly. That one was an epic fail by the previous tech ;-)
Having dealt with a whole bunch of lousy work (like this) by previous "repair" personnel, I have become a bit anal about solder connections :)
Yep, I understand ;-) Hey, are you familiar with conn organ stuff? I have a conn organ amplifier I want to rip apart and build into a new chassis, but I Cant find the schematic on it anywhere. it works great as is, and ive had it since 2003 or thereabouts. Back when you could get a complete chassis on ebay for $25 or so. Not anymore. Here is a link that has a picture of what it is: hxxps://www.worthpoint.com/worthopedia/conn-organ-tube-amp-59525-6l6-6v6-143234053
Having watched this video, I wondered if the choke was center tapped to use as a phase inverter. I'm sure you would have mentioned that. I would like to know more about the use of transformer s as phase inverters like in the Fender Music Master Bass amp. Especially how to choose the appropriate transformer for use as a pi. I would love to chat with you.
In this case, Mark, the choke was simply a dedicated filter choke and the 6N7 tube served as a paraphase inverter.
From what I can determine, there are two choices for PI transformers. You can use one with a 1:3 primary to secondary winding ratio, (pre-amp input to the primary and secondary output to the output tubes with CT grounded). See PT-156: www.tubesandmore.com/search/node/interstage%20transformer
A simpler method is the one Wurlitzer used in their 1940's jukebox amps. See my video: ua-cam.com/video/7E-lSEMnph4/v-deo.html and watch at 10:25 for the "Input Choke" #L3, which you could probably duplicate with the center-tapped secondary of transformer (with the primary unused). It's an interesting concept that I have not fully explored, but would like to, if time ever allows. There are also several sites and chat rooms with interesting discussions about interstage transformers and PI's.
sounds alot like my gibson br9 1949 model ,it has the original 2 prong cord I have not been inside this amp so dont know if any work has been done and havnt played it for 2 years and wont until it is looked at and 3 wire plug is installed,probably very simular to this design we shall see 1 day
Let us know what you find, Joe.
Very smart checking your new chassis ground instead of assuming that it works.
Cheers!
Thanks, Amo.
pop quiz...LOL that was GREAT!
I was a teacher for many years.....old habits are hard to break :)
Great video, really enjoyed it.Nice blues chords too, for a second I thought you were going to cheat us out of the customary surf riffs.
Greetings, TB, and thanks for the kind words. After several months of no practice, they were the only riffs I could remember :) Glad you liked the video. It's always good to hear from you.
Are you taking on more work? And if so, how can i get in contact with you?
+38018Memphis I do from time to time, but I'm real picky......only really old, tube guitar amps of small to moderate size (i.e. Princeton Reverb or smaller). You can contact me by personal message.
Nice. Never thought about making a strap like that.-Thanks.
You're welcome, WN. Glad you liked it.
Nice little amp. Spilled the popcorn all over me when i heard spider eggs. Lol
First Rule of Electronic Repair: No ancient amp circuit is complete without some spider eggs :)
Very interesting coarse! Thank you Uncle Doug..
You're welcome, Kevin.
Just out of curiousity, what would the incorrect phase inverter tube have done to the amp and / or its sound?
I have no way of knowing, Jon, but it would probably have been quite unpleasant.
liked the video but , i'm trying to figure out the order to watch them in ? please let me know thanx !
Greetings, TW. The videos can be broken down into three main groups: Basic Technical, Specific Amps, Jukeboxes.....plus some others thrown in for good measure. If you want to see the Basic Technical videos (for instance), then you should probably take a look at my channel index and make a list, starting with How Amps Work Part 1 & 2, then move on to Phase Inverters, Power Transformers, Output Transformers, etc. The specific amp videos and jukebox videos are not in any order. Good luck.....and good viewing :)
another great vid so interesting,wish i understood more of what was going on !!
'Dried out and worthless,' have you met my ex-wife?
I've never had the pleasure, Jeff ;)
you could plug it in if you connect a 300 watt blub in series with the line cord.
Greetings, BG. I did use a 250W Current Limiter every time the amp was plugged in. I consider it to be an essential tool and never do any testing or repair work without one. Thanks for your input.
test lamp and isolation transformer i use both
I recently purchased one of these for restoration and find your presentation invaluable. Much appreciated. Do these have transformer date codes or any other way of dating them? Thanks again for this and the numerous other videos of yours that I have enjoyed watching.
Thanks, Philip. Yes most components have date codes that can be deciphered using information from Internet sites dedicated to this purpose. Try some Internet searches and I think you'll find them.
The transformers did not have any obvious date codes nor did any of the caps. However, there was a good one on the speaker. The speaker is dated 1943, 44th week. So I assume the amp was made right at the end of 1943 or sometime during 1944.
Jesus...I thought my Magnatone (1948) was old.!
Speaking of which...it had a similar looking filter cap...like a small stick of dynamite...paper falling apart...elytic paste all dried up...and it also "took a charge" like yours did in your video. Amazing.
Hey.......what ESR meter do you have.? I have been wanting to get one, but I really have no idea which one to buy (or make). Does it measure in circuit by any chance.?
Would value your opinion on what to get in the ESR arena.
Thanks Doug
Greetings, Denny. Heck, even I am (a little) older than your Magnatone :) Those old electrolytics really are hardy aren't they.....like the Terminator at the end of the movie, torn to pieces and still crawling. I have an AnaTek Blue ESR meter. Here is a link: shop.anatekcorp.com/index.php?src=directory&view=products&srctype=detail&refno=2&category=Component%20Analyzers It works great, in and out of circuit. I know there are other brands, but it's the one I chose after analyzing what was available. You can get it assembled or in kit form (at a discount). It's a very helpful device to own.....definitely worth the money.
10-4
Thank You :-)
Uncle Doug, you are truly inspiring, sir.
Thanks so much, Bill :)
Metal amp cabinet.. Who knew?? Doug knows!!! Thank you, Sir!!!
It seems spooky to have all that voltage and current in a metal box, Abe, but that's the way they did it back in the old days :)
@@UncleDoug My other amp is housed in a 100% metal cabinet, hopefully with uk 240v in the grounding pin on the input socket for the power is not just for show. I will have to component check it I last used it 20 years ago, your easy to follow explainations are easier to follow than the written guides I have read in the past on the internet - I also have some old (1960s!) books and I find they either start pitched too low in knowledge, going into things you dont need to know about, or run too high in theory particularly on electron flows and capacitance issues (I still cannot follow capacitance maths for materials - in part as electrons do not behave in a linear - or even square or log functionality exactly ). Your overall - and one notes the benefit of a series build up that Public Broadcasting would never go into such detail on - approach of this it what it is, this it what it does and this is how it does it, makes sense.
good one. my bogen has the same inverter circuit using a 7N7
+Ronnie Marler Thanks, Ronnie. Glad you liked it :)
awesome as usual!
Thanks, D :)
Amazing video, Uncle Doug.
Thanks, MD. Glad you liked it :)
Wow ...back to the bare minimum...just enough gain from the paraphrase PI to make it work.
Para phase tnx spellchecker!
I love these early circuits :)
Survived covid, played dobro and lap steel for 30 years. Brings back memories. Hope you’re well, but I feel it’s best to get covid now before it mutates!
Thanks, Duane. The problem with viral mutation is that once the mutation occurs, depending on which part of the virus it affects, it may render the virus "invisible" to the immune system, allowing for re-infection. It's a problem with vaccinations or acquired immunity.....they only immunize against the known form of the pathogen, generally not its mutated form.
@@UncleDoug Not really a covid thread but what has been worked on on the latest vacine design is to learn the immune system to the ;protein; spike presentatio19n, which is the virus method of entry and internal cell movement , any mutation of that protein to avoid the immune response rapidly and effectively shutting it out, should make the entire virus less efficient at cell entry as normal cells only let in certain key pattens in proteins. (of course the theory may be proved wrong - coronaviruses have rarely been studied as to vacine as generally (common cold) they did not slaughter enough people or have the known and recorded long-tail effects that c-19 is kicking up - though I guess in the elderly they had enough of an effect - OC43 for example results in death of about 1 in 100 infected of older persons and appears to peak every other year - which suggests for that about a 12 month immunity effect with a seasonal cyclical poss Vit D for us northern hemisphere dwellers, as the effects though were mainly studied in nursing homes, perhaps the problem with residents was they did not get out for enough sun in summer - so your texas spring and autumn should assist you. The world-wide present problem is that the C-19 being generally about is reducing the ability to get round other folk in crowded low income countries for the vax programmes for other diseases,including TB . I hope thats a reasonable present day scientific analysis as I see it , though we may have to wonder why/if the present vaccines are only 70percent overall efficient, what is the 30percent loss caused by - though for the community 70percent is good enough for the poor individual rolling the dice and losing its not - I think the gap might close a bit with some further research and some of that efficiency is measuring the disease not the fatal direct outcome (which seems much much less with a vaccine than without)
Doug I have one of these as well. Thanks for sharing video
You're welcome, Kyle :)
Uncle Doug,
you're doing great without Rusty, he might get jealous when back from the Outback.
Good video and as usual, after your restoration, the amp works. I would love to have a tube tester as yours, but they are rather difficult to get - might be worth a video, showing how it works.
Greetings, TM, and thanks for your kind words. I am putting up a good front, but video production is much more challenging without Rusty's capable assistance. Re the tube tester, it's simply a device with a power supply, just like an amp, that powers up the tube, checks for shorts, and measures its output (in different ways). Here is an excellent site, describing the different types of testers and tests: en.wikipedia.org/wiki/Tube_tester
Thanks for the link, keep on going with more video's.
Ha Ha You did a great job, but I came to this video after listening to your Marshall JMP video, sound was obviously not the same.
No, it probably wasn't CF. Thanks.
@@UncleDoug I wonder if the sound would change a little if the rest of the capacitors were replaced ? Also using phase inversion in this method is there not a time delay so the final output is fractionally out of phase match - or is that what gives the sound its timbre - or at speed of light the delay is insignificant to the speed of sound ?
Wait, I'm confused. Is there no pre-amp tube? Or is the Phase Inverter acting as a pre-amp tube?
You answered my question in the video. I've never seen an amp with no pre-amp stage...fascinating
Glad you liked it, Jay :)
You could still do a push-pull amplifier with only having a single pentode in the preamp, and in fact, I can think of two ways to do it, off the top of my head. One is to use a self-split power stage, where the two power tubes act as a long tailed couple, while being the output stage at the same time. Another way sould be to use a transformer with split secondary winding as the phase inverter. The way Rickenbacker did it here is really clever and interesting.
I am only not sure by the way you grounded the third wire of the power lead. It is a good practice to make a separate lug that is only used for the ground wire. This ensures that the bolt will never come loose. In this case the heavy choke may rock and wobble a bit, and make the connection loose after some time. I have seen people connecting the ground wire to any bolt nearby, especially to a lug on a bolt that is mounting an IEC power socket, but this is really bad practice, as you risk the bolt, and therefore the ground wire, becoming loose at some point. Actually, I believe the only legal way to do it, in Europe at least, is to use a separate, dedicated lug for the ground wire.
Greetings, Kard. I was indeed looking for another transformer under the chassis plate that might act as a P.I....and when I first saw (what turned out to be) the filter choke, I thought that might be it :)
The P.I. method used by Rickenbacher is quite similar to the Gibson EH-150 (as mentioned in the video) and to the early Fender ("Woody") Model 26 Deluxe.
Your recommendation on the ground lug is interesting. I never considered the possibility of a nut coming loose, especially when a lock washer is used, but I will keep it in mind. Thanks for your input.
Uncle Doug
Yeah, I used to use whatever bolt happened to be near the power socket for the ground wire lug in my own builds too, until I got a good talking to from a professional guitar amp builder on an internet forum. Better safe then sorry, especially since your amp will surely still be in use another 70 years from now!
another great video, gotta love these 30s amps..
Thanks, Bill. I agree :)
Rusty sure taught you well Uncle Doug, another brilliant video cheers!!!
Thanks so much, Mudy. I would indeed be lost without Rusty's insights and guidance.
Uncle Doug Spock would b proud of U, live Long and Prosper - UD and Rusty, thanks as always :)
You're welcome, Mudy :)
You have a wonderfully dry sense of humor.
Thanks, William. It helps me accept life's ups and downs :)
Hi Doug, I was curious where you got your Capacitor ESR meter..? I would like to be able to single out the bad caps in my amp repair/restoration... is there a way to do this with a conventional DMM? Thanks for your time.
Greetings, Britt. It's from Anatek.....here is a link: shop.anatekcorp.com/index.php?src=directory&view=products&srctype=detail&refno=2&category=Component%20Analyzers It's best suited for testing electrolytics in circuit and is extremely useful. A DMM cannot perform the type of analysis that the ESR meter can. If you observe Christmas, it would be a good excuse to get yourself one.....as a present :)
Uncle Doug Are Anatek Blue meters still shipping? That's good news. I ordered my kit shortly after the gentleman who made them passed away and his wife was trying to fulfill remaining orders.
I have no idea about their current status, MD. I bought my meter over a year ago. Hopefully, they will be able to continue building and shipping them.....they are a good quality instrument.
Love your work Douglas. Always a pleasure and an education to watch your videos.
PS where's the dog ?
Thanks so much, Gary. As I said in several responses (below), to put Rusty's fans at ease, he was attending a family reunion in Australia, partying with his relatives and litter mates in Queensland. Glad you enjoy the videos :)
I thought Rusty had the look of a good Australian Cattle Dog about him. I actually live in Queensland & design/build/repair valve (tube) amps. All the best & keep up the good work Doug.
It's a small world, Gary. I'll say this about Queensland, you guys really produce some good dogs (and, no doubt, some good amps:). Rusty has been my pal for more years than either of us care to admit. He and I both send you our best West Texas regards.....:)
Thanks for sharing. I am currently fixing a mid-50's Gibson GA-20 amp. This info is a so helpfull.
Remarkable video and audio quality.
Best regards.
You're welcome, Marcel. We're glad you like our video format and content. Best of luck with your GA-20 repair.
The phase inverter is a version of a paraphase.
I agree.
The yellow capacitor was amazing! I was guessing (hoping) the phase inversion might be similar to your Magnatone Melodier until you showed the schematic. Beautiful repair work, and the sound is incredible. Hopefully Rusty returns tan and relaxed from his vacation. :))
Greetings, Andrew, and thanks for your kind words. It's always good to hear from you. The suspense was definitely building with regard to the phase inverter. I thought there might be a PI transformer hidden inside and assumed that the filter choke was it.....until closer inspection. At least we finally got to see a living, breathing example of the third type of phase inverter (as presented in the PI video), a type which was en vogue during the late 30's and early 40's. There is some gain provided by the Paraphase inverter, so I guess in this case it was a combo pre-amp and PI. The yellow capacitor will be ensconced in my Hall of Shame display.....visitation by appointment only.
I got a post card from Rusty. He is at Surfer's Paradise on the Gold Coast and having a great time. Hopefully he can spend some time with his litter mates while in Queensland, before returning home to resume his videography career. I'll give him your regards :)
Really cool old amp. I would love to run across something like that. I do have a Les Paul Jr. Gibson amp from the 50's.
I believe it was bought on Ebay, Ben. The LP, Jr. is a nice little amp.....its circuit is similar to a 5C1 Fender Champ.
uncle doug I still am not exactly clear on how the filter choke transformer works does it take the place of the full wave rectifier, or does it work in conjunction with it? and how exactly?
A filter choke is not a transformer, David. It's simply a large coil of wire.....like a Slinky. Coils impede the passage of AC, so it works with the FW rectifier to smooth out any ripple that remains in the DC that the rectifier has produced.
thanks again uncle doug, I found a good site called 300 guitars, just looking at the thing I assumed it was a transformer.
They do resemble transformers, David, but with only one winding, not several.
another good one doug, thank's,
+PAUL HAMMERSLEY You're welcome, Paul.....glad you liked it :)
Sometimes feel a bit sad when I have to get rid of old waxy caps because some come in very pretty cases. The heat shrunk covers of modern ones look all the same
+MisterTalkingMachine I agree, and tend to keep them if they are still in working order.
Thanks,Doug,for another interesting and informative video. I' m as excited as you were with the Ricanbacher.I've found an unusually good design for an Admiral phono amp,which I can't find a schematic either.It has a huge power and output transformers in it.5y3,6av6,12ax7,6sn7,6v6,6v6, and six controls! One labeled a hum control.Luckily,the same technician hasn't got in to this one yet...and it even works!
You're welcome, Arthur. The Admiral amp sounds like a good basis for a guitar amp conversion.....especially if it hasn't been harmed by a previous "tech". Best of luck.
Great video, and I really appreciate the educational parts as I'd like to learn more about analog amplification. Just wanted to say, I have a '64 black face Super Reverb with a two prong plug on it. I'm not going to change it but I'm really careful how I plug it in and what I touch when I'm plugged in, etc. It sounds awesome. Walk Don't Run had me smiling.
Thanks, BK. Glad you liked the video (and the surf riff :). I have a bunch of vintage amps with 2-wire cords and have no problems, but you have to periodically test them for potential to ground, like I did in the video. Best of luck :)
Awesome video uncle Doug
Thanks, Daniel. Glad you liked it :)
Thank You Uncle Doug
You're welcome, 330 :)
Thanks again Doug for showing us this little gem. Hope you and Rusty are well.
You're welcome, Colin. It's always good to hear from you. Rusty and I have never been better....thanks for asking :) ^. .^
So I used to have a barn amp I bought from a friend in high school. Brand was lectrolux or electrolux, cant really remember which. Anybody ever heard of it?
Internet searches don't turn up anything amp-wise, but without knowing the exact name, it's not going to be easy....especially since Electrolux vacuum cleaners swamp the responses. Maybe a viewer can shed some light on this mystery amp.
Ya I was kinda hoping you had come across one at some point, as I had the same problem trying to search online for it. Thanks for the quick reply :)
So I misremembered the name, it was lectrolab not lectrolux.
Well, John, I'm both surprised and happy to say that there are all sorts of sites and information about Lectrolab amps on the Internet. Here is a great site: lectrolab.wordpress.com/ You need to check out the different models they picture and describe, to see if you can identify your old amp. Good luck.
Wow, this is a beauty :)
Never had a chance to lay my hands on any piece of electronics that old...
Thanks for sharing and great job :)
BTW, what is the voltage rating of those caps you put in? Without the tubes it went up to almost 500V ;)
Also, I see you're not a fan of putting replacement caps into hollowed-out old ones? I do it from time to time, especially in case of those big screwed on multi-caps to preserve the looks.
Thanks, Stan. It's good to hear from you :) I agree that the voltage on the empty tube sockets exceeded the 450V rating of the caps, but I have seen this repeatedly with no dire consequences. Apparently the voltage rating has at least a +10% leeway. No, I don't generally try to hide new capacitors inside old ones, especially in cases like this where several of the old caps are not original. I will leave any visible old caps in place (i.e. the canned multi-caps), but hide the new caps inside the chassis. I guess if a customer requested it, I would....but so far, none have. Thanks for your input :)
Awesome clip as always Uncle D! Best amp circuit / electronics videos on UA-cam by a mile! Keep 'em coming.
Thanks so much, Tuomas.....glad you liked it :)
I love these videos. Thank you so much for making them.
You're quite welcome, Brian.....glad you enjoy them :)
Wow nice uncle Doug, I’m looking up filter choke right now, I love your videos and you are a great teacher because the more I watch the more I understand the terminology and what they mean when you talk about each separate circuit. Thanks again for everything you do.
You're welcome, David. Independent research, i.e. regarding filter chokes, etc., is a great way to learn. The Internet is a wonderful resource. I personally use it exclusively when doing research for videos.
Long time watcher but first time writer, Just thought I'd drop a line to thank you for these great videos. Keep them coming!!
You're welcome, Francisco. Rusty and I intend to keep producing videos until the old EE in the sky pulls our plug :)
This amp reminds me of the time, when I was a little guy back in the 50's our mom got a NEW refrigerator and it replaced the old one which sat right next to the light switch for the kitchen. If you weren't careful switching on the lights and brushed the fridge it would give you a healthy Zap. With that fridge we didn't need OJ to get us going in the mornings. We always loved when cousins slept over on weekends.
Greetings, MM. I guess we were just tougher back in the old days. I recall getting shocks of varying degrees on a regular basis....it was almost a routine event. We had a washing machine (in a cement-floored utility room) that was not grounded and if you were barefoot and touched it, you could get a pretty good jolt. Instead of suing the manufacturer, my parents just told us to wear shoes or not touch it....simple as that. Like you, I used it to torture my friends :))) Fortunately, none died.
great Video as always.
Thanks, Heinrich. Glad you liked it :)
thank you for the proper schooling...
Doug, another precious gem of restoration know-how. As always I laughed along constantly as you very patiently give your opinion on the atrocious state of the design and components. What an experience it would be to work as your apprentice! Hope Dear Old Rusty is keeping you busy.
Hi, Stony. It's great to hear from you. I'd like to think that videos like this one are a fairly close approximation of what it would be like to be here with Rusty and me while we wade through one of these old, mistreated circuits. It's really just a hobby to us, so we try to keep it light-hearted and irreverent.....but still focused on creating a nice, reliable result. Like my old granny used to say, "If it ain't fun....to hell with it!" :)
When you revealed the underside of that amp I just covered my face and shook my head....What a disaster it was!
It had definitely had some amateurish work done on the circuit, but at least it all turned out OK :)
Thanks for the videos. I really enjoy them and have learned a lot from them. Can you show us step by step how you analyze and draw a schematic on an unknown guitar amp.
You're welcome, Charles. The process of analyzing a circuit and drawing a schematic is one of those skills that comes from experience. Like playing a musical instrument, someone might try to explain all the steps, but the best way to learn is by personal application and study. Start out by analyzing a simple schematic like the Fender Champ. Once you understand every symbol and line, then move on to more and more complex schematics. Then try drawing your own schematic, being sure to include all the necessary components and connections. It's an incremental learning process.
thanks man! I laughed uncontrollably several times...
You're welcome, Kyle....glad you enjoyed the video :)
Love this vintage equipment. Thank you for all the useful information.
Bobby
You're welcome, Bobby.....glad you liked it :)
Uncle Doug
I was hooked when I watched your first Video.
All the best.
Bobby
As always, very interesting!
Good job Doug!
Thanks, Elix.....glad you liked it :)
we love a bit of danger,,, turn it up dude ;)
must admit,,, i do like the look from the rear,,, she's a pretty little thing.
I would agree, if it were my amp, but with customer amps, I tend to be a bit more conservative :)
Interesting circuit. I like the way the grid of the second triode in the phase inverter is given a little of the first triode's output to balance it more accurately as opposed to just connecting it to ground.
I take it the guitarist would adjust the volume on his instrument to suit, or failing that his playing style :)
Michael Fearnley Greetings, Michael. Yes, the Paraphase type of phase inverter is a very interesting design, and the only volume control would be the one on the instrument being used with the amp.
Uncle Doug Hmm. To me it doesn't look like a paraphase. If you look a little closer it's actually a long tailed pair phase inverter as both triodes share a common cathode. It looks a little like a paraphase, but the voltage divider that feeds the grid looks like it's there to perfectly balance the LTP by making up for the limited differential gain. It's a very neat little hack!
From a design point of view it seems fairly justifiable to improve the performance of the phase splitter with the addition of just one 20K resistor.
I too was initially fooled by the common cathodes (a feature shared by both types of inverter), Michael, but upon closer inspection, it is (IMHO) a classic Paraphase inverter. In a LTP, neither plate feeds back into a grid, as it does in the Paraphase; and, most damning of all, there is no "tail" resistor in this circuit, only a cathode bias resistor.
Uncle Doug Fair enough, we'll just have to agree to disagree. To me it looks like a differential LTP (as both cathodes share a resistor) with Paraphase correction!
You could just call it a paraphase but perhaps you could define it by which action creates the most differential gain. In that case I would call it an LTP.
Who knows? There's no right or wrong here!
Sounds good to me, Michael. Thanks for your input :)
ya gotta know what to do with somethin' like this~
It definitely helps, Jay :)
@@UncleDoug any evidence as to why the pentode had been acquired into it, other than that change back to the correct tube and the power supply side of changes - which really became obvious one the components were traced to power flow the actual physical work was fairly little. Like many engineering things its the tea-drinking musing and drawing the problem/solution that takes the time.
I certainly feel like you do! Please, keep these videos coming!
I will, Mopar. It's good to know that others share my appreciation for these wonderful old devices :)
I'm starting to find that on less common units like this the cost of the tubes alone renders the unit obsolete. With less common pre amp tubes going over $50 and your work, the bill had to be $400. Is the amp worth it?
Greetings, William. Actually, the 6N7 cost less than $5, and my bill was much less than your estimate....but I agree that restoring any vintage tube amp can get a little "pricey" especially if you pay someone else to do the work. Also, replacement of a vintage power transformer or speaker, if even possible, can make tube prices seem negligible.
I guess the key is to get the amp at a price that is low enough to allow for reasonable repairs, and be sure (as possible) that it does not have severe problems. There is some luck involved, and it helps to either be able to fix it yourself, or have access to a reasonable, competent individual who can.
I see people asking astronomical prices for old, beat up amps that are untested, as-is, and without return privileges. Since they value these amps so highly, my feeling is that they should be allowed to keep them.....at least until their value assessment becomes much more realistic.
Have an ampeg b12xy. Far more complicated. 6d10 went from 6 to $40. I was able to do small modifications to exchange 7199 to 6u8a and 7027 to 6l6gc but now I look and all the wires are cracking and resistor and capacitor melted off circuit board. I dont have the original bottom or reverb speaker. Is it worth fixing.
Some tubes, like the 7199 are really tough to get, and conversion to common tubes (as you have done) is almost mandatory. Re the Ampeg amp, I would say it was worth fixing only if you did the work yourself. If you hired someone else, it would cost more than it's worth, especially since it's no longer in original condition. There would have to be a strong, sentimental attachment to justify the expense.
Uncle Doug I appreciate your response and I enjoyed your video. I am an extremely handy individual and kept this thing running for more than 30 years with limited knowledge and also managed to not send myself across the room.......yet. is there something i could read that would transfer what i'm looking at on a schematic to whats in the housing. .
Not that I'm aware of.....it's a skill developed by doing rather than reading. You have to locate the main components, like the transformers, tubes, pots, etc.(i.e. landmarks) in the chassis and then correlate them with the schematic and trace the wires that connect them to the other components. In time it becomes easy and natural. Good luck.