Gibson saturn GA-45 RVT Tube guitar amp repair Fender Mod D-lab Part 2
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- Опубліковано 23 сер 2024
- This has been a long term project. I initially attempted to repair the Gibson as stock. After many hours of hair pulling, I decided to re-group and determine a better plan of attack. Well, here it is. Why fix it when you can simply install a Fender eyelet board! Yep, that is the plan and it worked excellent. Yes, it is a lot of work, but now this is a reliable and easy to work on amp. Hope you like
After reviewing pt. 1, I think you were so smart to do this mod! Gibson's philosophy, was to make their guitar amps sound bright and clear, like a Fender, when using a Gibson guitar with humbucker pickups, as we all know, are not as bright as single coil pups. The voice of their amps became chocked and brittle. If you played a Fender guitar through a Gibson amp, it was shrill, at higher volumes it was offensive. I remember in the late 60s, a lot of players would use a Gibson guitar with a Fender amp. Beauty! I guess your new nick name is Frank! As in Frankenstein! Great, great mod and video. This is why I love your videos! Tube Amp Thea-ta! Thankz
Absolutely love the Forbidden Planet shots! The all time best Sci Fi movie of the 50's thru the 60's. there just wasn't anything like it at that point. So well thought out & executed.
Nice conversion. Nice for the owner to not have to even worry about replacing all those weird tubes (6EU7, etc) any time in the future. Nice that the bones of the unit were decent, too. Nice job of adaption to the existing power xformer.
Had to do the same on many amps after they had been modded so many times.
Skilled engineers are like gold dust had to find.
Here in Scotland, the sunny part of it..I've been the trade for over 25yrs and carry out lots of amp repairs and it's good to see a enigeer pass on skills such as this.
Ha ha...."other than that, she pretty much stayed stock" 8:39 (Other than a whole innards replacement). All kidding aside, excellent work! Really enjoy your descriptions and learning. You articulate what you are doing extremely well! Top notch, Sir!
Yea I chuckled when he said that too!
Excellent transformation! Wow. The Gibson amp deserved to be gutted into some more useful. Great job!
You do good work there Mr Terry. Reminds me of a small Gibson tube amp I seen over 30 years ago at a pawn shop i played through it and it had a really sweet sound. That old Jewel had one of the best sounding reverb, it had a long decaying type that was a very close copy of the inputted sound. I've always preferred the tube sound over solid state, hard to beat that vintage tube sound.
Glad to see you didn't give up on this one!
Great idea on the conversion! Those Gibson later 60's amps were a grade A cluster***k! The layout and pots are perfect for the AB763 circuit. I'm sure the transformers will add a bit of Gibson tone to it.
Great video,very inspiring. I appreciate the videos that you do. In fact I just got my Technician Ham Radio license last week. Between your channel and the radio shop channel I am enjoying all the content being presented. :)
Nice job! I think old Leo new his stuff! The customer got a better working amp that's easier to repair if it ever needs it! Hope there's a demo of this beauty!
Man, now I'm going to be hunting down these amps for conversions. I make my own boards, both turret on fiberglass and eyelet on fiber boards. It's so much cheaper if you don't mind putting in 30 minutes of work.
It's hard to find some pre made boards for certain vintage amps. I like the 50's Gibson GA-40 and GA-15 amps and make the boards more like a Fender of the same era. I do it for the same reason you did, ease of construction and repair.
I am totally blown away by the paraphrase inverter. It's got a lot of gain(which I love) and doesn't have any headroom. The long tail pair makes for a better amp overall though. Try out the paraphrase circuit from the GA-40 or Fender 5C3, your customers might like it. You really only need 1 pre stage to get a lot of voltage swing so a parallel 12AX7 works great. 5879's or any other small pentode is another great option.
Awesome! And I love the bias pot and test points being easily accessible.
Nice job, Terry.
Thanks for the Tube Amp Theater. Great Video!
Awesome work, Terry. Wish I'd have thought of using a prefab board like that (I used a Weber generic board and cut it down to the length I needed; it worked, but the layout was not as elegant in execution as what you have) to save myself some trouble....this amp should be glad that it's now a defector...
Love that Forbidden Planet intro!
always fun to watch.
If I wuz a bit more mobile, I'd pack my favorite tone machines and see just what I expect your cool projects could do... tone wise, that is...plus enjoy some of your insanity...
Always feel like I'm learnin' sumpin... at least to type a bit quicker... thanx for another great vid and...
cheers
How cool...!! Nyms
I remember some of those Gibson and Epiphone amps back in the late 60s. Some were
a disaster as far as wiring layout and reliability. Gibson amps never really sold well in
my part of the country..everyone preferred Fender amps for reliabilty and punch power
like the twin reverb , bandmaster etc. Don't know why the Gibson wiring had to be
so messy, wired by a bunch of production line workers off the street I guess,never mind those tone sucking networks they put in most models to .
The amp department in Kalamazoo was set up by Ted McCarty with Walt Fuller and Seth Lover (inventor of the humbucker).
Funny how the Gibson humbucker/Les paul guitar became American musical icons, yet their amps which never sold well, faded into obscurity due to their mediocre reputation. In the end, the amp production stopped in the early 70s as sales dropped
off drastically due to a recession.
Thank goodness that Leo Fender knew how to come up with a good reliable design
and the rest is history.
I have one of these waiting in the long 'to do' line. One question, how come you changed to a Fender style reverb tank? Sorry if that was covered in Part 1 already. Haven't seen that one. ...and by the way, I have the Gibson Master Service book with all their schematics, if you ever need one, let me know.
The original reverb tank was bad, so I thought might as well go full Fender.
Dang that Fenson/Gibder sounds nice. I just bought a '65 Gibson Saturn GA 45 RVT. If I send it to you will you turn mine into a Fenson/Gibder Saturlux too?
Should it ever become available I would love to add it to my amp inventory. Would really get a charge out of watching my friends try and compare what they are seeing to what they are hearing.
Beautiful work! I have one of these exact amplifiers. Would you be interested in doing another? If so how much approximately would it cost? I am sorry but don't know how to private message you. Thank you, Mark
Nice!
I have a tube amp challenge for you. i cannot find a schematic for the tube amp. I have two rauland 2135. It is a 4 channel xlr input. Tube line up is 6 12ax7a pre amps, two el6ca7(using el43), and one 5asa4. It also has four rauland r1002coils on the input directly after the xlr line in. I presume for hi and low signal. Guessing powered and non powered mics. I have not seen you work on any amp like this one. It also has for an output transformer 70v, 25v, 16, 8, and 4 ohm outs. So monster output and input transformer. From what i can see the amp is original. So if i swap out the components(resisters, caps, and two diodes) I should have a working amp. What would you do? it has a 120 hum (constant) and a 60 cycle hum (when volume is applied) on the preamp. No signal in. Where do i start? should i just shotgun all the capacitors with the current values, test all the resistors, and hope for the best? Or, cut everything out and mod to a schematic i can find before I blow the transformers? On a side note. I love the tube amp theater and have learned a lot. Thoughts? questions? concerns? I would love any feedback. Thanks for your time and thank you for tube amp theater!
Gibson schematics are not easy to come by. I got a 63' GA-5T... the one with the 6AQ5's in it. The online schematic from Gibson is not a match.. I have the original paperwork for that amp... so thank heavens I have the schematic.
could you share it and upload it somewhere?
I have a GA45RVT like this one and I am thinking about doing what you did. Would you recommend doing it or just trashing the thing and building a Fender AB763 from scratch?
These amps sound pretty good when working right, would pass it on rather than converting it
Would this be equal to a Vibrolux or maybe a Pro Reverb?
Do Gibsons have the same mounting locations as Fenders? (1:38)
Nope, I had to drill and add standoffs
Nice Gender Amp. Is the heater wire on pin 7 of the output tube from the transformer, which looks like original wiring, dry?
would that be a "Trans Gender amp"
Yep, that was the original connection. I will be inspecting and dressing up connections+ wiring when it nears completion.
Man this Gibson am sounds like a Fender!
20 hours plus materials... That must have been pretty damn spendy.
totally disagree, just roll your tone down on yer single coil guitar, voila! or better yet play a Gibson/Epi through a Gibson amp---melted butter!
I can't believe I'm the only person in these comments that's cringing at the idea of gutting a vintage amp... As much as I like your videos, this one was hard to watch. I'm very disappointed.
Im sorry you feel that way my friend. D-lab is a repair shop. I do as asked by the customer. This amps fate was the dump unless we reached a solution. Now it is good for another 50 yrs of life with a happy owner. I have no regrets. TD
That's where I disagree. The amp was fixable, only you had the wrong schematic. There are several differences between a GA-45RVT and a GA-45RVT Saturn.
You talked about the removal of the twin T circuits being a workable solution to the issues of the amp but those sections of the circuit are significantly different on the Saturn.
I'm not trying to be argumentative and I know you do what the customer asks, but it seems like this was a case of the customer following your lead while you went down the wrong path. Now, the amp is no longer vintage and that's unfortunate.
Again, I truly like your channel, but IMO this was a drop of the ball.
Roger that Sir. I see your point. Thanks for sticking with D-lab
No, he didn't rebuild an amp. He gutted one and replaced it with another. He can do what he likes, I never said he couldn't. But the value of the amp has dropped compared to what it would have been if it were a repaired original circuit.
As far as what I "do"? I'm a professional musician that builds and repairs amps as a hobby. I'll fully admit that I don't know as much as I should, and you can call me a cork sniffer, but I do know the value of amps.
You are right about one thing though, it's not my amp so what I think doesn't matter. Just like your opinion about what I said. It doesn't matter.
If this were any other amp I might agree with you, but both the Saturn and non-Saturn version get terrible reviews because they are just plain bad designs. I too would have replaced the guts with something else.
You really cant call this a repair.
Terry I love watching your vids. You are generous and kind.
And quite silly at times. Nice job there. Your a good teacher. Very talented. It is a very good vocation for you. 😅 very profesional work. Im also a ham operator my call is KC4ITU the last sol. Flux 2 days ago was 173 wow perhapps I'll catch you on the ether sometime. Dwight.