1966 Gibson GA-35 RVT Lancer Guitar Amp Renovation Part 1

In this Part 1 of a two-part series, a newly purchased 1966 Gibson GA-35 RVT is inspected and evaluated. Part 2 will cover the internal components and required repairs in detail. I hope this is of interest and assistance, particularly if you are working on a similar amp. Please subscribe to see all of my other videos of vintage jukeboxes, guitar amps, and restoration methods....and please check out the numerous related videos on my companion channel, ElPaso TubeAmps. Thanks for your time and interest.

[@UncleDoug]

Ed, I have finished the GA-35 and it is working beautifully. The Reverb is insane, but the Tremolo is a little weak (which I believe is fairly normal for these amps). I intend to record and upload Part 2 in the very near future. One suggestion I would make is to check your tubes carefully.....I had some problems in that area. Thanks for the compliment on the Mighty Mouse/Bassman....the "Mouse that Roars" :)

[@JamesMcCutcheon]

My RVT 35 is brittle shrill and its microphone tube, not warm as some of the others I have heard. its in project stage thanks for your review.

[@UncleDoug]

You're welcome, James. Please see my video in which I solve the brittleness issue and greatly improve the tone of the RVT 35.

[@moodyga40]

love your videos Doug i have started building valve guitar amps you give me inspiration

[@UncleDoug]

ian forster Thanks so much, Ian. I'm glad the videos were inspirational. Best of luck with your projects :)

[@moodyga40]

i have a question i am a bit rusty with the ohms law i need to know how to work out the bias resistor for a 6v6 i am using cathode bias resistor. or just work out cathode bias resistors in general. i have a plate EHT is 290 thanks ian 

[@bullet0657]

Hey uncle Doug i am relay looking foreword to future videos of the lancer. I recently bought a Epiphone futura amp that is like this and needs help. ps nice job on the little bassman.

[@UncleDoug]

Jason Durham, unless you activate Google +, it is impossible to directly respond to your inquiries. For now, I'll answer up here. Sorry, but I know of no source for original Gibson amp parts, but you can find good substitutes at Antique Electronic Supply in Tempe, AZ and good transformers at Triode Electronics. Good luck.

[@TheGalaxyhopper]

yep looks like my old amp!

[@jeromestevenfaigin6059]

Hi Uncle Doug & Rusty with the cat (Jack?). I'm a new listener and Devoted to the tube sound or at least the tube pre-amp like my Peavey T. G. Raxx (with the 4 12AX7As). Why 4 tubes and a rackmount, I don't know? But my homemade Teles sound so much more dynamic over straight solid state. I've got to say, you remind me of my dad's TV repair shop, South of Holly - weird with the Sam's photo faxes, the test equipment (the sound generator, a BK scope & Old RCA vom meters - two I believe) I got when close down and I was doing the grunt work and suffering latter with major back problems. So my big question is, what do you do with the restored equipment? I started learning music at 7 and now at 58 (with a very damaged back of nerve damage) it takes everything I got to tune up, clean up, change strings and play for no one else, but myself! If I don't do this everyday, hours of playing, the pain is worse! There's something therapeutic of playing everyday when I play and build guitars. I plan (if I make a lot more) to sell my collection when I'm ready, plus sell any left over wood and parts left over. Is that or something similar to what you do? If I wrote anything too personal or putting my foot where it doesn't belong, please disregard and not answer this question. Thank you for your time and keep video-owing, Jerome

[@UncleDoug]

+Jerome Steven Faigin You're welcome, Jerome. Yes, my workshop is probably a lot like your dad's. Much of my equipment is from the good old days, including a (nearly) full set of (huge) Rider's radio schematic volumes. I go through long periods of gradual acquisition and then am forced periodically to "prune the tree". I list larger items on Craigslist for local sale and pickup, and smaller, shipable items on Ebay. My last Ebay amp sell-off was at least a year ago and all 6 amps met or exceeded my price expectations.

[@JasonDurham1]

I have a Gibson G35 and am looking for parts. Any idea where I can pick up replacement parts? Thank you!

[@Guitarwizard456]

Uncle Doug I have a Gibson GA35RVT that I am restoring and I need to replace the pot for the volume and the reverb there are no ratings on the pots only part numbers that don't mean anything to Antique radio supply can you tell me what the ratings are since the original parts are no longer available ? The numbers on the pots are CBA-4007 and CBA-4008 also they have a number1376610 and 1376620 on them.

[@UncleDoug]

This is where schematics are very helpful, GW. According to the schematic for the GA35RVT, the 4007 pot is 500K Audio Taper, and the 4008 pot is 250K audio taper. Both pots were made by CTS in the 10th and 20th week of 1966. Good luck with your restoration.

[@Guitarwizard456]

@@UncleDoug Uncle Doug thank you for the info But I am puzzled because when I removed the old pots I tested them and get a reading of 296K for the 4007 and 456K for the 4008. I have a 500K linear taper pot on hand is that compatible for a 500K audio taper? I tried it where the 4007 was for the volume control and the amp works but it seems to be a very low output. . Can that be my problem or would it be something else ? I never heard how the amp was supposed to sound like before I start on it only going by you video of the same model. I also noticed on your amp they were using a 12AX7 mine has a 12AU7 in that spot . Is that the wrong tube?

[@Guitarwizard456]

Uncle Doug thank you for the info But I am puzzled because when I removed the old pots I tested them and get a reading of 296K for the 4007 and 456K for the 4008. I have a 500K linear taper pot on hand is that compatible for a 500K audio taper? I tried it where the 4007 was for the volume control and the amp works but it seems to be a very low output. . Can that be my problem or would it be something else ? I never heard how the amp was supposed to sound like before I started on it. I'm only going by your video of the same model. I also noticed on your amp they were using a 12AX7 mine has a 12AU7 in that spot . Is that the wrong tube?

[@UncleDoug]

What value should the two pots have? Linear taper and audio taper pots are not interchangeable. Their response curves are different but they both yield the same final volume. The 12AX7 has much higher gain.....so it would increase the low volume you are experiencing.

[@Guitarwizard456]

@@UncleDoug you told me in a previous reply that the 4007 is supposed to be 500K and the 4008 is supposed to be a 250K so the 12ax7 is interchangeable with the 12au7 and there is no problem with having either one there. That's good to know I will get some audio taper pots to replace the ones I need but still wondering why the difference in the value from what i tested it seems opposite of the info you gave me about them.