Hey there, I have a suggestion for you. I've been watching through your videos and I've noticed you tend to use your drill for installing and removing screws in amps. Dewalt makes a gyroscopic powered screwdriver (model DCF680 $89) that folds into a gun shape like the drill or can be used straight like a screwdriver. I've found it to be fantastic for working on amps, especially vintage ones that you really dont want to slip and scratch the chassis. It weighs a fraction of what the drills do, and is small enough to very easily get into tight spaces, especially with the folding feature. Because its gyroscopic the amount you twist your hand controls the power so you can do really slow delicate work like vintage flat head screws, but is still powerful enough to drive a 3 1/2" screw into wood without pilot drilling. I got mine several years ago and I can't imagine not having it for working on amps now. Just thought I'd throw that out there. Thanks for the videos, excellent presentation.
Rasjase1, Ryobi makes a somewhat similar, *hinged* , battery-operated, rechargeable driver/drill screwgun that can be used either straight-on or folded into a pistol-style handle. It's not gyroscopic, but costs less than 30 bucks [edit, it's actually $39.95 at Home Dumpo] if I remember correctly. I haven't tried the DeWalt you mention but we had a gyroscopic Black and Decker driver/ drill at the electronics repair shop I used to work for and I never really cared for it. I prefer a trigger operated driver-drill, but perhaps that's just me, because I've been doing carpentry and construction type work all my life and I have a well-educated trigger-finger!
@@goodun2974 that's sounds cool, especially for the very low price tag. I've tried a few other gyroscopic devices and I understand, a lot of them are pretty unremarkable. This particular 1 however is pretty neat. You can do neat things like take a flat slot screw and fast spin it most of the way in, and then slow it down to snail pace at the end to put the slot orientation exactly like you want it without over tightening or slipping out. Also with delicate things like plastic or aluminum screws or very small ones, you have so much control that it's easy not to mess them up. I've seen them on display at various big box hardware stores, definitely worth checking out. The other big thing is battery life. When I was still working as an electrician I'd use it on a 12 hour shift on literally like hundreds of screws and it would still be around half charged or close to it when I got home.
@@rasjase1 , my larger battery-powered tools are mostly Milwaukee (3 various sized driver drills, a hammer drill, impact driver, mini Sawzall, circular saw,, plunge cutter, and soldering iron), but for disassembling electronics and for small projects around the house I use a small Ryobi pistol-shaped driver drill with 1/4 hex-drive socket and two speeds ---- primarily because it's physically smaller than any of the Milwaukee driver drills. My Ryobi has swappable batteries (the other hinged ones I mentioned earlier have integral batteries). The batteries for the Milwaukee tools are expensive, but awesome!
@@rasjase1 , an update: the Tek4 series of Ryobi tools, including my original fixed-pistol-grip 200/600 RPM driver-drill (with separate, swappable Lithium battery and LED work-illumination) was discontinued (I got mine cheaply nearly a year ago as a closeout). The current-production Ryobi hinged driver-drill ($40 at Home Dumpo) that converts from pistol-grip to a straight handle has a built-in (integral) lithium battery, still two-speed ( 200/600 RPM), but doesn't have the LED'S to illuminate the work area (darn!). However, True Value sells a similar hinged/pistol- grip convertible screwdriver (under their Master Mechanic house brand) with integral lithium battery, fixed 180 RPM speed (adequate for screwing, maybe not as good for drilling), and has not only 4 LED'S to illuminate the work area but an actual LED flashlight built into the butt end of it ---- for the ridiculous price of $25 bucks here on the East Coast! I bought one yesterday but haven't had a chance to put it to work yet.
She's deff the hottest amp repair-guy around these days and all this talk about amp components, voltages and capacitors is unexpectedly melting my foolish heart like warm butter!
wooow. this amp!! .. youtube had decided tonight to present me your chanel... and your video brought back some childhood memories... during school my friends and i formed a band, not the best band in the world, but we had fun and one of us even has become a sucessfull professional musician. we played on what cheap instruments we could afford, but for a while the uncle of our sax player let us kids use his beautifull strat that was vintage even at this time and the amp that went along with it. It was one like the one you work on... and it was one wonderfull amp to me, when i could plug my cheap squire tele in... . phantastic that you keep this one alive!! I like the way you explain your work. and subscribed. (p.s.: a while ago i reactivated after some decades my old squire tele and started playing again.. and meanwhile, i have inherited from a uncle of mine a vintage messa boogie blue angle, that manages to bring back the same feeling of cool that the fender did back in the days... )
You might like the recent Tone Master deluxe reverb. It's a digital amp so it's real light to carry and it has most of the same features of the original.
@@aniquinstark4347 I saw Phil's McKnight's review. It didn't really inspire me. I'm using a Strauss 15w amp that was modded by a genius amp tech called Warren McAllister. it's sweet and light.
Dude I have a '71 Twin sitting in the corner of my kitchen waiting to be rebuilt! Thanks so much - this provided a ton of useful insights. Any tips on a weak reverb sound? Tank looks physically OK, thinking it may be components. Love your channel!
All hail to Uncle Doug. Brad could learn from this woman, but, he's too busy crying about everyone else's business. No whining here. No trash talk.. Just "This is How and Why"!! Colleen executes the task at hand as if she were one of Uncle Doug's top students.
I’m so happy to see that Uncle Doug has spun off such an excellent and confident technician. Great editing work. Really nice. Glad to know there will be service techs in the decades to come.
Nice pacing. You get to the point. Why do we find enjoyment in watching these? Do accountants watch videos of people working on spreadsheets? I dunno. But I find it relaxing.
Nice to see a young person embrace this kind of old school electronics! I'm a retired Navy Electronics tech and worked on a lot of this kind of vacuum tube circuits back in the day. Color me subscribed!
Thanks for the video, I probably watched it a dozen times. I just did this to my Dads 70 Twin Reverb that's been sitting since he passed away 18 years a go. It sounds great. You made it look easy. Thank you for helping me get my Dads vintage amp working again.
Excellent video and repair. You have a healthy respect for preserving the amp and it’s history while honoring what made it a great amp to begin with in your restoration. I have learned so much from your videos, thanks for posting them! You’re an inspiration to me, as I just restored a ‘69 twin reverb.Keep up the good work!
Oh man, this is mannah for the mind. As an old solder-head I love the fact that you get the camera in so close to the work so we get to really see the detail. Great work.
Dude Colleen I’m just now watching this and this amps birthday and mine are a day apart 😭 thank you so much for fixing my dads amp without taking all the soul out of it. It still smells like our old house.
I'm so glad I found this. I have the same 71 Twin Reverb and it's very special to me since I inherited it from my Grandpa. I had it apart before to replace the power cord and clean up everything. The caps looked surprisingly ok, but I still want to replace them in the future. Thanks for the step by step! Also, thanks for explaining the biasing process.
Just a suggestion. The ground lug on the transformer mounting screw is not necessarily better than a wire soldered to the chassis. However, if you're going to use a lug, you might want to add a second locking nut to make sure the lug is never loose. It's insurance, like the silicone on the caps. Subscribed! Looking forward to your videos!
Regarding Bias; The Trainwreck Pages by legendary amp guru Ken Fischer states that the safe operational range of 6L6, EL34, etc. is between 10-40mA per tube at idle, so anywhere between these settings that produces the tone you desire is the "correct" setting. This particular Fender, as with any given Marshall, etc. might sound best at 15mA per tube... or it might sound best at say, 35mA per tube. An amp with a higher bias (lower current) will have more clean headroom, and tend to have more crunch. With a lower bias (higher current) the amp will generally sound beefier with a quicker break up. With the customer playing through the amp; run the gamut of safe current range... and see what the customer likes... you'll generally hear a "yeah, right there, that sounds great". You can then consistently repeat that exact bias current when replacing that customers tubes... thereby saving yourself time... and keeping a very happy client that will probably bring more work your way. 👍🎸
Great video and excellent demonstration of your work. You may have miscalculated with the bias settings. 26mA @ 450v would be 11.7 w which is very cold for 30w 6L6 tube. I'd guess you accidentally used the spec for 6V6. I've subscribed 😄
Cool video! I've just bought 1975 twin reverb, and they are hard to come by in Ukraine. Had to fix reverb transducer's loose wire, other than that the condition is 4/5. What a gem. Thanks, it'll help me a lot when I'll be ready to take mine apart to see what needs fixing/replacing.
I had that exact amp from '86 to '93, when I scored an early Vibro-King in perfect original, still working, (no hum on orig caps) on a pizza delivery for $600! I used to go to the Hollywood guitar shops in the 80's and buy their old Fender amp chassis' (mostly) to learn amp repair. They'd sell me brown face and black pface for $30-40. There was no Groove Tube amp bible, just RCA manuals and I had a set of four 1950 US Army Electronic study manuals. Being handy, I was able revive nearly every amp. A great solid state amp to play electric or acoustic guitar through is the FET transistor 1976 Ampeg G110 W/ REVERB and TREMOLO. The DeArmond D240 wire wound + piezo acoustic hole pickups are worth their weight in gold!
Tip from a guy who was doing this in the 60s & 70s: See those white capacitors (at around 15:20) ? Those happened to be Mallory but were often from GE, who came up with the idea of molding them in nylon (which GE plastics just happened to make). These are a problem, since nylon is hygroscopic (absorbs moisture). Guaranteed that they are changed in value and will eventually fail. They were such a bad idea the GE quit making capacitors like this altogether, as did Mallory. Any time you see them, replace 'em! The only reason they lasted longer in guitar amplifiers, is because they have an oven underneath to dry out the moisture (i.e. the tubes heat up the entire amplifier from underneath!) Nice job in modifying and adjusting the Bias. Most were set too high, which caused more power to be used and shortened the useful life of the output tubes (and even some of the cheaper transformers).
1971 Was a vintage year for this amp all hand made in California USA . No Imported parts like the 2021 amps . I wonder how many different guitarists have played it . Well it's finally in the hands of a woman who takes care of all the electronic components . Thank You Colleen .
I’m flabbergasted at the fact UA-cam promoted a channel I’d actually be interested in. Even though I know how to fix/restore/build tube amps, it’s nice to see other people doing it. You just might pick up a new trick. I agree with not changing the bypass caps, they only see a few volts and usually go high which gives more gain. You can really screw up and amps “mojo” by shotgunning everything. Pickup yourself some paint gun cleaning brushes from Harbor Freight. They come in a kit, ranging from small to large and they’re perfect for cleaning tube sockets and jacks.
@@FazioElectric , I've never seen a wire-bristle brush small enough to fit inside the contacts of a12AX7 socket, and while nylon-bristle brushes plus a solvent will clean out greasy grime and dust, they are too soft to remove tarnish and corrosion effectively. A tip I learned from an old electronics repairman is to use a piece of round-wound guitar string, size .036 to .039, as a sort of miniature round rasp or file (a phosphor bronze string is nice and hard, works particularly well), and work it back and forth inside the socket contacts, then flush with non-residue solvent; and if need be, retension the contacts with a jeweler's screwdriver or dental pick (as you showed here). If you can find a way to adapt a segment of guitar string to fit into the chuck of a miniature rotary tool, like the smallest Dremel-style tool you can obtain, then cleaning sockets becomes very fast and easy. (I use a Tihoo battery-powered artist's eraser, with a modified chuck arrangement, to spin the guitar string. EDIT: I also use battery-powered erasers with a short segment of fiberglass bristle-brush, or a 4 mm silica impregnated eraser rod inserted, for cleaning and polishing tarnished metal contacts and the backs of pots prior to soldering. Anyone who works on electronics really needs a set of " scratch brushes", especially the glass-bristle brush ---- but I advise you to wear gloves!).
Matt, for some reason the local Harbor Freight doesn't carry paintgun tip-cleaning brushes, but one alternative is to buy dental brushes at the drugstore, the type used to clean around bridges and other dental prostheses. Although as I noted below, nylon brushes are too soft to remove decades of tarnish and corrosion.....
Yes.thinking a cool dream situation. 1st of all,me hate indiana,where me at.would be cool to go to Venice beach.although not as cool as it was in 1970's, it still cool.ok,then take my fender super reverb,my hagstrom super swede guitar,my cat.let my cat be free on beech,then play the cooles music anybody did hear!!!!
Wow! I've never delved into what it takes to service these things (just a player - I can service guitars but amp stuff scares me!), and obviously it takes a lot of knowledge and experience. I'm amazed that someone so young has this depth of knowledge and experience. I only stopped by because I once owned a Twin of similar vintage. Almost everything went over my head here, but it was quite impressive watching someone methodically work through the issues. Not sure I have what it takes to learn this kind of thing, but I'm glad there are folks like you that do!
A little unsure about your biasing method. 467 plate volts x .032A = 14.9 watts dissipation. This is for two tubes since the cathodes are tied together, correct? If so then you have 7.5 watts per tube, which is about 25% max diss. for a 6L6. Why are you thinking this is on the high side? I wouldn't have lowered it, myself. Also, I know you are trying to keep it stock, but I also would have wired the primary of the PT to modern code, black to fuse, fuse to switch, switch to PT. White directly to PT, using an unused lug of the now nonfunctional ground switch, since the death cap would have been removed. No amp leaves my shop with any potentially hazardous electrical wiring, regardless of the customer's romantic views of keeping everything stock. Otherwise, good job.
Only a sugestion, I'm a repair technician since I was 13 - Now 68 - and the flux and soldering fumes are dangerous, please use even a single mask to prevent from its inhalation, I developed an alergic reaction from that fumes that leds me not to interrupt totally from my job - I'm retired now but still working, in a very slow rate - mostly of the 55 years ago I used to repair tv sets and by 21 years I was an employee from Embratel in BRAZIL, repairing shf transmission equipment, very nice and professional your job, keep posting your videos !
I failed electronics class in high school and didn’t understand most of that, but I found it fascinating nonetheless. Cool video, I’ve got to dig into your channel more
@@zhou_sei I graduated from high school 35 years ago. In addition to electronics class I also had to take wood shop, metal shop, and Home Economics. It’s a shame that they don’t teach that stuff in school anymore
Move over Uncle Doug, Brad and Terry! I have a new channel to tune to for amp repairs 😅 Just kidding! I still love you I called the "Big 3" but glad to see this new channel! Great job and looking for more amp repairs in the future! 👍
I've been fooling around with electronics for 50 or so years...I learned more in this 18 minutes from a lass around 1/4 my age than I could believe!! Now as I prepare to build a Mojotone Deluxe Reverb kit, I am wondering how I'll set the bias etc??? Well done Electric Lady...well done!
Dig - The 5881 tube will fail in a 6L6GC circuit. Much lower max plate voltage and dissipation ratings hence having to make the bias current value less.
THERE IS A MOD FOR THIS SILVERFACE THAT CONVERTS IT TO TWO-SEPARATE AMPS - A FENDER PRO & THE FENDER TWIN. GERALD WEBER DESCRIBES AND DETAILS THE CIRCUIT CHANGES TO THIS AMP IN "VINTAGE GUITAR" MAGAZINE - PROBABLY FROM THE MID 1990'S. USE AN A/B/AB SPLITTER TO RUN INTO BOTH CHANNELS - YOU CAN HAVE A PRO OR A TWIN...OR THE COMBO OF BOTH SIMULTANEOUSLY .
This is so great. I spent 14 years doing this stuff and you explain and film it so well. Love the laid-back delivery and lack of bullshit music and nonsense.
When restoring my early '70s Bandmaster Reverb I found an ultrasonic cleaner works great for cleaning small parts, such as knobs. Also did a great job cleaning my '74 Les Paul Standard's Tune-O-Matic bridge.
A real joy to watch you working on that, even more so because you clearly understand the importance of keeping old technology alive. Congratulations on choosing a meaningful and satisfying path!
Good job girl, first time running across your channel. Just a suggestion, I’d go up a little on your soldering iron wattage. Looks like you have maybe 25-30W iron there. I’d go 40 watts on this old stuff. More mass to sink the heat away. Heat up those eyelets quick, flow some solder and get off of it. I wasn’t feeling real groovy about your solder joints on the filter caps, but all good. I liked that you took some interest in getting the cabinet fixed up better.
You know your trade well. I am not surprised to see a lady doing this work because I had many ladies taking electronics in my classes during my 20 years teaching it at Harper Collage, Palatine Ill. Doc Brown.
You have to compare AX7/7025's in the gain hole(s) to get a good idea of their microphonics. This is something that an amp owner can do themselves... try swapping all your compatible pre tubes into the V1/V2 (gain hole) position, you may find that a 'microphonic' tube works fine as a trem oscillator or reverb recovery tube, and that the tube in that position is a better first stage. The noisiest tube is the first one in the chain... don't be alarmed when you hear noise here, swap them around to get a true idea. Don't forget to dime the input volumes and tones to give worst-case noise.
The mains ground conductor should be attached to a fastener that is used exclusively for that purpose. Never attach it to hardware that is being used to secure a transformer or any other component.
While I don’t think I’ll ever dive into working on any of my own amps, it’s really cool to soak up a little knowledge and watch the work being done. I could watch these vids all day - mesmerizing.
Might be helpful to elaborate a little more on a few things, like the importance of keeping track of polarity with electrolytics. I have no doubt that you know what you're doing, not so sure about the rest of us haha. But great video. Thorough repair.
You should see if you can find some neutral cure silicone for gluing down components. Standard silicone, aka acetoxy silicone, releases acetic acid as it cures (thus the vinegar smell), and this can cause corrosion to metal parts over time.
I'm very grateful to you for showing us how to fix these amps. You're so clear and you don't waste time on unnecessary commentary. Wonderful to see a young woman fixing amps.
I just stumbled across your channel, pretty impressed so far. I'm a repair guy myself, but amps are just a hobby. Nice clean work here, and a pleasant video to watch. Glad to see two of my faves on board here too- the Guitologist and Uncle Doug! 😲 Kudos!! 😁
For removing solder from tube pins I love using MG Chemical flux coated 2mm solder wick. I like the 2mm chisel tip for my Weller too for point to point work. The tip mass retains its temperature better and recovers faster when cooled.
I know nothing about electronics but I do dabble in music. It’s always so satisfying watching someone who is really good at something doing it with passion. Well done. Your ring finger on your right hand has the rank of Corporal. 😁
Question! The screen resistors leads on my Deluxe reverb are extremely short, straight from pin to pin. Will an extra 1/4" of leads from the ends of the resistors have any impact on the performance or sound? Love your work!
note: many older amps have underrated filter capacitors, and rely on the output tubes loading down the power supply so the capacitors aren't strained, (they would probably be fine anyway since older capacitor voltage ratings are usually quite a lot lower than they can actually take) so running an old amp with the original filters without the output tubes in place may blow the filter caps. that's also the reason why when you replace the filter capacitors, you should check the max voltage that that node reaches, and not trust the original capacitor rating to be correct.
I'm an electrical engineer and I've done my pedal and stuff but those old amp... They scare me. When I ""grow up"" I wanna be like you 😅, fantastic video.
Great video. A better choice for cleaning pots is the Caig F5 moving fader lubricant. The Deoxit D5 is a contact cleaner that over time eats away carbon off the wiper disc.
Fantastic job! How did you get into this stuff? (14:43 Tremolo not vibrato. Tremolo is a low frequency oscillating of the volume/amplitude, and vibrato is low frequency oscillating of pitch. I dont think pitch could be modulated 50 years ago, but amplitude could.) You are a great role model for young women.
Hi Colleen. Thank you for making this video and for the channel. I really appreciate your teaching style. You get to the point, include the important stuff, and explain the rational behind the repair solution. Keep up the great work! I am a novice and just finished up my first Quad Reverb restoration / head conversion...wish I had caught this video first. I'm headed back in now to swap out the screen resistors and re-bias. Wish I had caught this video prior. Rock on! Great channel.
Sovtek data sheet indicates maximum plate voltage 250 volts and you're running 465 volts. Is that OK? I have an Engl Screamer 50 combo with Engl branded 5881's and I'm considered to change them. The schematic says that the circuit runs at 450 volts. Even Tung-Sol 5881's have maximum plate voltage 400 volts. Can you go over that?
Bonus karma points for soldering those caps so the next tech can read the values without desoldering them. Mark of a great technician.
I could watch these all day long. I mean I am watching these all day long. Love your channel!
@@hayeshargrove Don't you love her madly .....
Hey there,
I have a suggestion for you. I've been watching through your videos and I've noticed you tend to use your drill for installing and removing screws in amps. Dewalt makes a gyroscopic powered screwdriver (model DCF680 $89) that folds into a gun shape like the drill or can be used straight like a screwdriver. I've found it to be fantastic for working on amps, especially vintage ones that you really dont want to slip and scratch the chassis. It weighs a fraction of what the drills do, and is small enough to very easily get into tight spaces, especially with the folding feature. Because its gyroscopic the amount you twist your hand controls the power so you can do really slow delicate work like vintage flat head screws, but is still powerful enough to drive a 3 1/2" screw into wood without pilot drilling. I got mine several years ago and I can't imagine not having it for working on amps now. Just thought I'd throw that out there. Thanks for the videos, excellent presentation.
Thank you so much for the recommendation- I will be looking into that :)
Rasjase1, Ryobi makes a somewhat similar, *hinged* , battery-operated, rechargeable driver/drill screwgun that can be used either straight-on or folded into a pistol-style handle. It's not gyroscopic, but costs less than 30 bucks [edit, it's actually $39.95 at Home Dumpo] if I remember correctly. I haven't tried the DeWalt you mention but we had a gyroscopic Black and Decker driver/ drill at the electronics repair shop I used to work for and I never really cared for it. I prefer a trigger operated driver-drill, but perhaps that's just me, because I've been doing carpentry and construction type work all my life and I have a well-educated trigger-finger!
@@goodun2974 that's sounds cool, especially for the very low price tag. I've tried a few other gyroscopic devices and I understand, a lot of them are pretty unremarkable. This particular 1 however is pretty neat. You can do neat things like take a flat slot screw and fast spin it most of the way in, and then slow it down to snail pace at the end to put the slot orientation exactly like you want it without over tightening or slipping out. Also with delicate things like plastic or aluminum screws or very small ones, you have so much control that it's easy not to mess them up. I've seen them on display at various big box hardware stores, definitely worth checking out. The other big thing is battery life. When I was still working as an electrician I'd use it on a 12 hour shift on literally like hundreds of screws and it would still be around half charged or close to it when I got home.
@@rasjase1 , my larger battery-powered tools are mostly Milwaukee (3 various sized driver drills, a hammer drill, impact driver, mini Sawzall, circular saw,, plunge cutter, and soldering iron), but for disassembling electronics and for small projects around the house I use a small Ryobi pistol-shaped driver drill with 1/4 hex-drive socket and two speeds ---- primarily because it's physically smaller than any of the Milwaukee driver drills. My Ryobi has swappable batteries (the other hinged ones I mentioned earlier have integral batteries). The batteries for the Milwaukee tools are expensive, but awesome!
@@rasjase1 , an update: the Tek4 series of Ryobi tools, including my original fixed-pistol-grip 200/600 RPM driver-drill (with separate, swappable Lithium battery and LED work-illumination) was discontinued (I got mine cheaply nearly a year ago as a closeout). The current-production Ryobi hinged driver-drill ($40 at Home Dumpo) that converts from pistol-grip to a straight handle has a built-in (integral) lithium battery, still two-speed ( 200/600 RPM), but doesn't have the LED'S to illuminate the work area (darn!). However, True Value sells a similar hinged/pistol- grip convertible screwdriver (under their Master Mechanic house brand) with integral lithium battery, fixed 180 RPM speed (adequate for screwing, maybe not as good for drilling), and has not only 4 LED'S to illuminate the work area but an actual LED flashlight built into the butt end of it ---- for the ridiculous price of $25 bucks here on the East Coast! I bought one yesterday but haven't had a chance to put it to work yet.
Nice work. Love amp repair videos. My best friend is a 70 year old amp tech. I get to be his most of his repairs.
What a war torn amp. Been in a lots of bars. My kind of amp.
As my uncle who worked on electronics would have said “That one has rocked many a barn full of drunks.”
She's deff the hottest amp repair-guy around these days and all this talk about amp components, voltages and capacitors is unexpectedly melting my foolish heart like warm butter!
I was in 3rd grade; LZ’s “Immigrant Song” and B.J.Thomas’ “Raindrops Keep Fallin’ on my Head” were first played through these amps.
Nice work. Old Pyle Driver speakers, had a few in my day. Great video on a amp close to my heart. Have 2 in my stable.
Great clean work!
I never think Ill watch a whole video, then next thing you know, I'm an amp repair expert.
Bravo , fantastic video!
wooow. this amp!! .. youtube had decided tonight to present me your chanel... and your video brought back some childhood memories... during school my friends and i formed a band, not the best band in the world, but we had fun and one of us even has become a sucessfull professional musician. we played on what cheap instruments we could afford, but for a while the uncle of our sax player let us kids use his beautifull strat that was vintage even at this time and the amp that went along with it. It was one like the one you work on... and it was one wonderfull amp to me, when i could plug my cheap squire tele in... . phantastic that you keep this one alive!! I like the way you explain your work. and subscribed. (p.s.: a while ago i reactivated after some decades my old squire tele and started playing again.. and meanwhile, i have inherited from a uncle of mine a vintage messa boogie blue angle, that manages to bring back the same feeling of cool that the fender did back in the days... )
Great story - I love that this video brought back such a vivid memory for you!
Excellent video. I have a 1970 Twin Reverb I did quite a bit of work on. Think I need to recheck the bias after watching your video. Thanks
I had one of these. It got too heavy to lift. Funny how they get heavier as you get older.
You might like the recent Tone Master deluxe reverb. It's a digital amp so it's real light to carry and it has most of the same features of the original.
@@aniquinstark4347 I saw Phil's McKnight's review. It didn't really inspire me. I'm using a Strauss 15w amp that was modded by a genius amp tech called Warren McAllister. it's sweet and light.
Dude I have a '71 Twin sitting in the corner of my kitchen waiting to be rebuilt! Thanks so much - this provided a ton of useful insights.
Any tips on a weak reverb sound? Tank looks physically OK, thinking it may be components.
Love your channel!
Coolest girl in town.
At 15:00 those white Mallory capacitors were notorious bad quality caps...
The perfect woman.
how does silicone stop them from vibrating?
Very nice work, Colleen.....and an excellent video to document it. Thanks for posting !!
Praise from Uncle Doug on an amp repair video is like a shiny gold star on your homework paper
I love having you here Uncle Doug!
Uncle Doug!!!
Just found your channel, Great work, just subbed. Uncle Doug rules too. Keep the vids coming.
This doesn't mean you can rest on your laurels Uncle Doug!
Love the sound and feel of this video. No distracting/annoying music, just the sound of the work and your description. Great editing. Subscribed!
+1 for the no annoying music 😊
Uncle Doug and the Guitalogist are on board; so am I.
Subscribed!
All hail to Uncle Doug. Brad could learn from this woman, but, he's too busy crying about everyone else's business. No whining here. No trash talk.. Just "This is How and Why"!! Colleen executes the task at hand as if she were one of Uncle Doug's top students.
@@y00h0011 AMEN
I’m so happy to see that Uncle Doug has spun off such an excellent and confident technician. Great editing work. Really nice. Glad to know there will be service techs in the decades to come.
Who is uncle Doug?
@@christopherskipp1525 famous tube amp you tuber instructor
He didn't teach her, a guy in Chicago did that she worked for.
@@Blueguitar007 Yeah, they have some different ideas, but Uncle Doug is incredibly knowledgeable and also like this lady, a good explainer .
@@seancurran6727 I didn't say he wasn't ok.. I said she got trained working at a shop in Chicago. She's got a whole video with her mentor.
Nice pacing. You get to the point. Why do we find enjoyment in watching these? Do accountants watch videos of people working on spreadsheets? I dunno. But I find it relaxing.
That’s too funny.
it's called inclusion /inˈklo͞oZHən/
i'm pretty sure accountants even find spreadsheets boring, but then again... i do know an accountant that likes tax time.
Servicing vintage Fender amps is the most chill thing in the world to me. Thank you.
OK. I did about 100 of them in the 90s. Nice to think most of them may still be working.
First time seeing your channel. Great job! Welcome to the amp repair club.
Thanks for checking it out! It’s great to be part of the club 😎
T.G where is your Bias Master huh?
@@mannyfragoza9652 she got them beat, plus, easier on the eyes XD (don't worry Brad, your still sexy, jajaja)
@@TononiaWorld F.E. is like listening to ASMR. She is wise past her years
@@mannyfragoza9652
ㅇㅓㅐ9.
Nice to see a young person embrace this kind of old school electronics! I'm a retired Navy Electronics tech and worked on a lot of this kind of vacuum tube circuits back in the day. Color me subscribed!
Well thank you so much! That means a lot coming from you- I bet you've worked on some really cool equipment. Thanks for the comment :)
@FazioElectric hi, I hace a one of this and when I push reverb footswitch the noise is coming very hard, what can I do ? Tks
I am electric engineering but I don't know valv amps functioning
Can you help me with a orientations.?
@diegotasende look it up, mr. electric engineering
Thanks for the video, I probably watched it a dozen times. I just did this to my Dads 70 Twin Reverb that's been sitting since he passed away 18 years a go. It sounds great. You made it look easy. Thank you for helping me get my Dads vintage amp working again.
Excellent video and repair. You have a healthy respect for preserving the amp and it’s history while honoring what made it a great amp to begin with in your restoration. I have learned so much from your videos, thanks for posting them! You’re an inspiration to me, as I just restored a ‘69 twin reverb.Keep up the good work!
Oh man, this is mannah for the mind. As an old solder-head I love the fact that you get the camera in so close to the work so we get to really see the detail. Great work.
Dude Colleen I’m just now watching this and this amps birthday and mine are a day apart 😭 thank you so much for fixing my dads amp without taking all the soul out of it. It still smells like our old house.
Mine too! 420!
I'm so glad I found this. I have the same 71 Twin Reverb and it's very special to me since I inherited it from my Grandpa. I had it apart before to replace the power cord and clean up everything. The caps looked surprisingly ok, but I still want to replace them in the future. Thanks for the step by step! Also, thanks for explaining the biasing process.
Just a suggestion. The ground lug on the transformer mounting screw is not necessarily better than a wire soldered to the chassis. However, if you're going to use a lug, you might want to add a second locking nut to make sure the lug is never loose. It's insurance, like the silicone on the caps. Subscribed! Looking forward to your videos!
My thoughts exactly.
Regarding Bias; The Trainwreck Pages by legendary amp guru Ken Fischer states that the safe operational range of 6L6, EL34, etc. is between 10-40mA per tube at idle, so anywhere between these settings that produces the tone you desire is the "correct" setting. This particular Fender, as with any given Marshall, etc. might sound best at 15mA per tube... or it might sound best at say, 35mA per tube. An amp with a higher bias (lower current) will have more clean headroom, and tend to have more crunch. With a lower bias (higher current) the amp will generally sound beefier with a quicker break up. With the customer playing through the amp; run the gamut of safe current range... and see what the customer likes... you'll generally hear a "yeah, right there, that sounds great". You can then consistently repeat that exact bias current when replacing that customers tubes... thereby saving yourself time... and keeping a very happy client that will probably bring more work your way. 👍🎸
Great video and excellent demonstration of your work. You may have miscalculated with the bias settings. 26mA @ 450v would be 11.7 w which is very cold for 30w 6L6 tube. I'd guess you accidentally used the spec for 6V6. I've subscribed 😄
Totally agree
Cool video! I've just bought 1975 twin reverb, and they are hard to come by in Ukraine. Had to fix reverb transducer's loose wire, other than that the condition is 4/5. What a gem. Thanks, it'll help me a lot when I'll be ready to take mine apart to see what needs fixing/replacing.
I had that exact amp from '86 to '93, when I scored an early Vibro-King in perfect original, still working, (no hum on orig caps) on a pizza delivery for $600! I used to go to the Hollywood guitar shops in the 80's and buy their old Fender amp chassis' (mostly) to learn amp repair. They'd sell me brown face and black pface for $30-40. There was no Groove Tube amp bible, just RCA manuals and I had a set of four 1950 US Army Electronic study manuals. Being handy, I was able revive nearly every amp. A great solid state amp to play electric or acoustic guitar through is the FET transistor 1976 Ampeg G110 W/ REVERB and TREMOLO. The DeArmond D240 wire wound + piezo acoustic hole pickups are worth their weight in gold!
Tip from a guy who was doing this in the 60s & 70s: See those white capacitors (at around 15:20) ? Those happened to be Mallory but were often from GE, who came up with the idea of molding them in nylon (which GE plastics just happened to make). These are a problem, since nylon is hygroscopic (absorbs moisture). Guaranteed that they are changed in value and will eventually fail. They were such a bad idea the GE quit making capacitors like this altogether, as did Mallory. Any time you see them, replace 'em! The only reason they lasted longer in guitar amplifiers, is because they have an oven underneath to dry out the moisture (i.e. the tubes heat up the entire amplifier from underneath!)
Nice job in modifying and adjusting the Bias. Most were set too high, which caused more power to be used and shortened the useful life of the output tubes (and even some of the cheaper transformers).
You saved that from being another dust collector or worse. Outstanding tech vid ! Thanks !
The editing on this one was spot on!
1971 Was a vintage year for this amp all hand made in California USA . No Imported parts like the 2021 amps . I wonder how many different guitarists have played it . Well it's finally in the hands of a woman who takes care of all the electronic components . Thank You Colleen .
Dude glad to see some who cares for the old kick ass amps! I am a vintage guy all the way. I have a 1972 super reverb and a 1978 music man hd130 212
I’m flabbergasted at the fact UA-cam promoted a channel I’d actually be interested in. Even though I know how to fix/restore/build tube amps, it’s nice to see other people doing it. You just might pick up a new trick. I agree with not changing the bypass caps, they only see a few volts and usually go high which gives more gain. You can really screw up and amps “mojo” by shotgunning everything.
Pickup yourself some paint gun cleaning brushes from Harbor Freight. They come in a kit, ranging from small to large and they’re perfect for cleaning tube sockets and jacks.
That's a good suggestion, I will give those brushes a try!
@@FazioElectric , I've never seen a wire-bristle brush small enough to fit inside the contacts of a12AX7 socket, and while nylon-bristle brushes plus a solvent will clean out greasy grime and dust, they are too soft to remove tarnish and corrosion effectively. A tip I learned from an old electronics repairman is to use a piece of round-wound guitar string, size .036 to .039, as a sort of miniature round rasp or file (a phosphor bronze string is nice and hard, works particularly well), and work it back and forth inside the socket contacts, then flush with non-residue solvent; and if need be, retension the contacts with a jeweler's screwdriver or dental pick (as you showed here).
If you can find a way to adapt a segment of guitar string to fit into the chuck of a miniature rotary tool, like the smallest Dremel-style tool you can obtain, then cleaning sockets becomes very fast and easy. (I use a Tihoo battery-powered artist's eraser, with a modified chuck arrangement, to spin the guitar string. EDIT: I also use battery-powered erasers with a short segment of fiberglass bristle-brush, or a 4 mm silica impregnated eraser rod inserted, for cleaning and polishing tarnished metal contacts and the backs of pots prior to soldering. Anyone who works on electronics really needs a set of " scratch brushes", especially the glass-bristle brush ---- but I advise you to wear gloves!).
Matt, for some reason the local Harbor Freight doesn't carry paintgun tip-cleaning brushes, but one alternative is to buy dental brushes at the drugstore, the type used to clean around bridges and other dental prostheses. Although as I noted below, nylon brushes are too soft to remove decades of tarnish and corrosion.....
Nice tip on tube socket and paint sprayer brushes!
I love seeing these amp restorations! Thanks for posting
Yes.thinking a cool dream situation. 1st of all,me hate indiana,where me at.would be cool to go to Venice beach.although not as cool as it was in 1970's, it still cool.ok,then take my fender super reverb,my hagstrom super swede guitar,my cat.let my cat be free on beech,then play the cooles music anybody did hear!!!!
Wow! I've never delved into what it takes to service these things (just a player - I can service guitars but amp stuff scares me!), and obviously it takes a lot of knowledge and experience. I'm amazed that someone so young has this depth of knowledge and experience. I only stopped by because I once owned a Twin of similar vintage. Almost everything went over my head here, but it was quite impressive watching someone methodically work through the issues. Not sure I have what it takes to learn this kind of thing, but I'm glad there are folks like you that do!
A little unsure about your biasing method. 467 plate volts x .032A = 14.9 watts dissipation. This is for two tubes since the cathodes are tied together, correct? If so then you have 7.5 watts per tube, which is about 25% max diss. for a 6L6. Why are you thinking this is on the high side? I wouldn't have lowered it, myself. Also, I know you are trying to keep it stock, but I also would have wired the primary of the PT to modern code, black to fuse, fuse to switch, switch to PT. White directly to PT, using an unused lug of the now nonfunctional ground switch, since the death cap would have been removed. No amp leaves my shop with any potentially hazardous electrical wiring, regardless of the customer's romantic views of keeping everything stock. Otherwise, good job.
Good job. For once UA-cam recommends something interesting.
Only a sugestion, I'm a repair technician since I was 13 - Now 68 - and the flux and soldering fumes are dangerous, please use even a single mask to prevent from its inhalation, I developed an alergic reaction from that fumes that leds me not to interrupt totally from my job - I'm retired now but still working, in a very slow rate - mostly of the 55 years ago I used to repair tv sets and by 21 years I was an employee from Embratel in BRAZIL, repairing shf transmission equipment, very nice and professional your job, keep posting your videos !
I failed electronics class in high school and didn’t understand most of that, but I found it fascinating nonetheless. Cool video, I’ve got to dig into your channel more
high school electronics? that's cool!
@@zhou_sei I graduated from high school 35 years ago. In addition to electronics class I also had to take wood shop, metal shop, and Home Economics. It’s a shame that they don’t teach that stuff in school anymore
Move over Uncle Doug, Brad and Terry! I have a new channel to tune to for amp repairs 😅 Just kidding! I still love you I called the "Big 3" but glad to see this new channel! Great job and looking for more amp repairs in the future! 👍
I've been fooling around with electronics for 50 or so years...I learned more in this 18 minutes from a lass around 1/4 my age than I could believe!! Now as I prepare to build a Mojotone Deluxe Reverb kit, I am wondering how I'll set the bias etc??? Well done Electric Lady...well done!
Dig - The 5881 tube will fail in a 6L6GC circuit. Much lower max plate voltage and dissipation ratings hence having to make the bias current value less.
Really enjoyed your video! I heard about you on The Truth About Vintage Amps podcast, good stuffs!
THERE IS A MOD FOR THIS SILVERFACE THAT CONVERTS IT TO TWO-SEPARATE AMPS - A FENDER PRO & THE FENDER TWIN. GERALD WEBER DESCRIBES AND DETAILS THE CIRCUIT CHANGES TO THIS AMP IN "VINTAGE GUITAR" MAGAZINE - PROBABLY FROM THE MID 1990'S. USE AN A/B/AB SPLITTER TO RUN INTO BOTH CHANNELS - YOU CAN HAVE A PRO OR A TWIN...OR THE COMBO OF BOTH SIMULTANEOUSLY .
This is refreshing. My amp guy's a junkie.
Hmmmm? Wonder if a domestic cat can walk on sand? Never seen this before.very interesting study onto itself.
This is so great. I spent 14 years doing this stuff and you explain and film it so well. Love the laid-back delivery and lack of bullshit music and nonsense.
When restoring my early '70s Bandmaster Reverb I found an ultrasonic cleaner works great for cleaning small parts, such as knobs. Also did a great job cleaning my '74 Les Paul Standard's Tune-O-Matic bridge.
A real joy to watch you working on that, even more so because you clearly understand the importance of keeping old technology alive. Congratulations on choosing a meaningful and satisfying path!
Good job girl, first time running across your channel. Just a suggestion, I’d go up a little on your soldering iron wattage. Looks like you have maybe 25-30W iron there. I’d go 40 watts on this old stuff. More mass to sink the heat away. Heat up those eyelets quick, flow some solder and get off of it. I wasn’t feeling real groovy about your solder joints on the filter caps, but all good. I liked that you took some interest in getting the cabinet fixed up better.
Wish I found this before I left LA last month.
You know your trade well. I am not surprised to see a lady doing this work because I had many ladies taking electronics in my classes during my 20 years teaching it at Harper Collage, Palatine Ill.
Doc Brown.
the old twin reverb with those heavy speaker magnet, i remember breaking my back carrying these to a few rehearsals lol. great job on the restoration
Needs wheels or a custom Dolly and strap mechanic.
@@TheWickerShireProject i sold it in favor of a Vox AC30 which is a lot lighter
@@leegeddyfan Too funny. Thanks for responding. 1 year later
You have to compare AX7/7025's in the gain hole(s) to get a good idea of their microphonics. This is something that an amp owner can do themselves... try swapping all your compatible pre tubes into the V1/V2 (gain hole) position, you may find that a 'microphonic' tube works fine as a trem oscillator or reverb recovery tube, and that the tube in that position is a better first stage. The noisiest tube is the first one in the chain... don't be alarmed when you hear noise here, swap them around to get a true idea. Don't forget to dime the input volumes and tones to give worst-case noise.
Plot twist: she's removing parts to build her own all original vintage frankenst'amp... 🤔 🤖
The mains ground conductor should be attached to a fastener that is used exclusively for that purpose. Never attach it to hardware that is being used to secure a transformer or any other component.
While I don’t think I’ll ever dive into working on any of my own amps, it’s really cool to soak up a little knowledge and watch the work being done. I could watch these vids all day - mesmerizing.
Might be helpful to elaborate a little more on a few things, like the importance of keeping track of polarity with electrolytics. I have no doubt that you know what you're doing, not so sure about the rest of us haha. But great video. Thorough repair.
Thought of that when she reworked that dog house lol. She's good, though.
I highly recommend this knowledgeable and skilled repair technician.
You should see if you can find some neutral cure silicone for gluing down components. Standard silicone, aka acetoxy silicone, releases acetic acid as it cures (thus the vinegar smell), and this can cause corrosion to metal parts over time.
I'm in love!
That's a high mileage amp for sure. I bet the owner has had plenty of hours of enjoyment. Salute from a fellow solder jockey.
I'm very grateful to you for showing us how to fix these amps. You're so clear and you don't waste time on unnecessary commentary. Wonderful to see a young woman fixing amps.
I will watch people repair amps ALL. DAMN. DAY. So cool to see new people joining the fray!
Why 5881s when this amp was designed to be 6L6GC, pretty big difference in my opinion
If there's one thing a Twin *doesn't* need, it's to be louder.
Great respect Lady😌...you sure know how to repair tube amps !
I just stumbled across your channel, pretty impressed so far. I'm a repair guy myself, but amps are just a hobby. Nice clean work here, and a pleasant video to watch. Glad to see two of my faves on board here too- the Guitologist and Uncle Doug! 😲 Kudos!! 😁
Nice repair and information...Cool amp, nice to see a new techy to learn from and a lady also..Keep up the awesome work..Ed..U..K.😀
Watching your skill makes me realize that I'm an idiot!
Amazing videos, great educational content.
Sound very relaxing .. sleepy
For removing solder from tube pins I love using MG Chemical flux coated 2mm solder wick. I like the 2mm chisel tip for my Weller too for point to point work. The tip mass retains its temperature better and recovers faster when cooled.
I know nothing about electronics but I do dabble in music. It’s always so satisfying watching someone who is really good at something doing it with passion. Well done. Your ring finger on your right hand has the rank of Corporal. 😁
Question! The screen resistors leads on my Deluxe reverb are extremely short, straight from pin to pin. Will an extra 1/4" of leads from the ends of the resistors have any impact on the performance or sound?
Love your work!
The resistor lead going to the screen pin should be as short as possible to avoid possible oscillation isues of the output tube
OMG!!! A beautiful woman repairing beautiful amps, I need you in my life!!! Subbed
That sounds phenomenal after you finished! Beautiful restoration.
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In the intro the size of the twin picture made me feel like it was some kind of crazy giant amp lmao
note: many older amps have underrated filter capacitors, and rely on the output tubes loading down the power supply so the capacitors aren't strained, (they would probably be fine anyway since older capacitor voltage ratings are usually quite a lot lower than they can actually take)
so running an old amp with the original filters without the output tubes in place may blow the filter caps.
that's also the reason why when you replace the filter capacitors, you should check the max voltage that that node reaches, and not trust the original capacitor rating to be correct.
That amp turned 50 last week
I'm an electrical engineer and I've done my pedal and stuff but those old amp... They scare me.
When I ""grow up"" I wanna be like you 😅, fantastic video.
The Fender Twin is a solid, great amp! Nice restoration!
Great video. A better choice for cleaning pots is the Caig F5 moving fader lubricant. The Deoxit D5 is a contact cleaner that over time eats away carbon off the wiper disc.
I only play thru the Axe III for the last 2 years. But I haven’t sold my Marshall or Mesa stacks yet. Interesting channel, I’m subbed. 👍
Fantastic job!
How did you get into this stuff?
(14:43 Tremolo not vibrato. Tremolo is a low frequency oscillating of the volume/amplitude, and vibrato is low frequency oscillating of pitch. I dont think pitch could be modulated 50 years ago, but amplitude could.)
You are a great role model for young women.
Great no-nonsense vid, and excellent lunchtime viewing. Thanks!
Well done! Having Uncle Doug's admiration is indeed another feather in your cap. SUBSCRIBED!
Cut the Power Cord...Smoke floats by!!! Nice effect for thought...Ha...A hair frizzing moment...
Hi Colleen. Thank you for making this video and for the channel. I really appreciate your teaching style. You get to the point, include the important stuff, and explain the rational behind the repair solution. Keep up the great work! I am a novice and just finished up my first Quad Reverb restoration / head conversion...wish I had caught this video first. I'm headed back in now to swap out the screen resistors and re-bias. Wish I had caught this video prior. Rock on! Great channel.
Sovtek data sheet indicates maximum plate voltage 250 volts and you're running 465 volts. Is that OK? I have an Engl Screamer 50 combo with Engl branded 5881's and I'm considered to change them. The schematic says that the circuit runs at 450 volts. Even Tung-Sol 5881's have maximum plate voltage 400 volts. Can you go over that?