Hey Brad,I wanted to help ya out with the wood type in the amp .all three pieces are redwood,bottom,and both side pieces. The piece with the white sap wood strip at the edge toward the speaker side of the board is what's called quarter sawn. The other piece with no white sapwood strip is what's called half or flat sawn. You my friend are a amplifier professional,best I've ever seen. I on the other hand happen to be a 35 year veteran wood professional. But again the wood in the amp truly is redwood,there are probably web pages out there to back my statement. id Google quarter-sawn and half and or flat sawn wood annual ring profiles . in my wildest dreams I would have never thought an amplifier company would have ever used redwood in amp construction. However it's an excellent choice because it is extremely light in weight and as durable as it needs to be for an amplifier cabinet. Keep up the good work friend I love your videos. Frankie Rapp >>>>----------->
Busted!! For the rock at the end? Say it ant so!!!...thank you for this and all of your great vids. this vid got me to buy one of these and o love it - We have a great tech in the area who went over it and got it all checked out, and He also loved it. keep rocking!!
I thought I had seen all of your vids, but guess I missed this one...lucky me I caught it!! What a sweet sounding amp (great tones!!)...and (with original tubes, etc.) in such good shape too!! You were playing such soulful, melancholy riffs...had to go back and watch it twice!! Awesome job!!
I have a GA-20T saved from an outdoor junk pile. It's truly awesome. I like to crank it up pretty high. Cranked all the way, or nearly, with the neck pickup volume cut just a tiny bit might be my favorite setting. I have a late 70's SG with the tarback pickups and they make an epic pair. Like I think you said, the distortion is really there right out of the chute. Fine with me lol, but that surprised me for such an early design. but what do I know... The tone control is equally non linear and most of the tone options are probably in about 1 to 3. When I first saw these videos, I thought, This guy should pattern a new amp design starting with this as a prototype. I've been temped to do it myself. I can do tube tech and builds as long as they are not too complicated, but I'm no engineer. It has that difficult to work on weird board in there that has a lot of components on the back side. A point to point layout would be way more awesome, and I suspect you could quite it down a bit. It's noisy. I would also add a phono jack for external speaker cabs that cuts the built in speaker, a mod I'd like to make on mine someday. I tried jumping the inputs together as some recommend, but it's noisy AF.
Brad, I’m building an amp into an old Hilgen chassis, I’m basing my channel 2 on the Gibson GA20T channel two’s 5879 preamp, channel one is a 6G4 Princeton. My question is my channel two will not have a tremolo circuit, but will have the .005uf,/1mΩ tone shaping circuit. Will the lack of the tremolo and it’s tube have an effect on the function of the circuit?
Maybe you could tell me what to look for .my bright channel.on my 59 twin don't work normal channel works fine.is there different tubes or caps that supply the different channels.
I have a 1962 Ampeg reverb rocket virgin amp with a major problem hum and no vibrato. Should I replace all the tubes from vintage tube supply 80 or $90. 
Hum could come from a few different problems depending on the type of hum. It could be tube related, but it's most likely cap related. Does the hum persist whether the volume is up on the amp or not? Have your tried turning the amp on and pulling tubes out one by one starting with the first preamp tube? Try that. sometimes that can give you clues about where the problem is.
The Guitologist Ah...I had a feeling it would be one of those 212 or 210 open-back "bass" combo amps from before they realized what they needed to do for it to work well with bass. Is that sort of a bassman copy?
Not a Bassman copy. There is a schematic for it online. Definitely Valco's own. I'm doing some mods on it right now because it's not as loud as I think it could or should be, and tehre's a lot of noise in the signal.
The Guitologist I have a random question. Is it normal to just always have noise when neither hand is touching the strings or the bridge on a tele? It's actually like very loud 60 cycle hum, and it goes away when I put hands on any metal part, so I don't really care that much, but does that technically mean my tele isn't grounded properly?
I had the same amp looking like new out of the shop, that was until local repairman Miha Slapsak told me he "can't get replacement 6SQ7 tube" and gave me 20eur of material for "pro audio preamp" based on industrial British preamp. So amp stayed in thief's shop, preamp was not worth the effort because it was never meant for pro audio tasks.
Not all redwood has that straight grain ....I think the side you think is not redwood is in fact redwood! I have worked with redwood and that grain is found
Hey Brad,I wanted to help ya out with the wood type in the amp .all three pieces are redwood,bottom,and both side pieces. The piece with the white sap wood strip at the edge toward the speaker side of the board is what's called quarter sawn. The other piece with no white sapwood strip is what's called half or flat sawn. You my friend are a amplifier professional,best I've ever seen. I on the other hand happen to be a 35 year veteran wood professional. But again the wood in the amp truly is redwood,there are probably web pages out there to back my statement. id Google quarter-sawn and half and or flat sawn wood annual ring profiles . in my wildest dreams I would have never thought an amplifier company would have ever used redwood in amp construction. However it's an excellent choice because it is extremely light in weight and as durable as it needs to be for an amplifier cabinet. Keep up the good work friend I love your videos.
Frankie Rapp
>>>>----------->
That may be the greatest guitar sound I've ever heard!!
Busted!! For the rock at the end? Say it ant so!!!...thank you for this and all of your great vids. this vid got me to buy one of these and o love it - We have a great tech in the area who went over it and got it all checked out, and He also loved it. keep rocking!!
I thought I had seen all of your vids, but guess I missed this one...lucky me I caught it!! What a sweet sounding amp (great tones!!)...and (with original tubes, etc.) in such good shape too!! You were playing such soulful, melancholy riffs...had to go back and watch it twice!! Awesome job!!
Great video Brad! Sounds amazing! Thanks for the great jams as always. B
Great sounding Amp and nice playing!!!!🎸🎸🎸👍🏻😊
I hear some Triumph and Wishbone Ash in your playing. Love your channel, you always cover the best amps!
I have a GA-20T saved from an outdoor junk pile. It's truly awesome. I like to crank it up pretty high. Cranked all the way, or nearly, with the neck pickup volume cut just a tiny bit might be my favorite setting. I have a late 70's SG with the tarback pickups and they make an epic pair. Like I think you said, the distortion is really there right out of the chute. Fine with me lol, but that surprised me for such an early design. but what do I know... The tone control is equally non linear and most of the tone options are probably in about 1 to 3. When I first saw these videos, I thought, This guy should pattern a new amp design starting with this as a prototype. I've been temped to do it myself. I can do tube tech and builds as long as they are not too complicated, but I'm no engineer. It has that difficult to work on weird board in there that has a lot of components on the back side. A point to point layout would be way more awesome, and I suspect you could quite it down a bit. It's noisy. I would also add a phono jack for external speaker cabs that cuts the built in speaker, a mod I'd like to make on mine someday. I tried jumping the inputs together as some recommend, but it's noisy AF.
Really enjoy your videos, thanks for posting them. Nice playing as well, very Neil Young.
I appreciate the comment. iI've never been a huge fan of Neil Young, but I appreciate some of the tones he gets.
Amazing tone there Brad... You iz Soo right.
So many different notes were feedingnnnnnnnnnnnnnnnnnnng
back................nice
I am a beginning guitar player and would love to learn that song your playing when you first start. Its awesome!!
Beautiful use of feedback and tremolo!!
Love that controlled feedback ....Great site Brad ...
Nice tone and playing. +1 on the good kind of feedback comment. You always have such cool toys to play with.
Will you pick up one of the new Falcons and take a look? I noticed they went with this aesthetic.
Great videos
hey Brad another great video my friend !! i hope you an your family are doing great !!1 Keep up the great work & much love to you my friend..... Chuck
Thanks Chuck! Appreciate ya.
nice playing.amp sounds awesome
Does anyone have a Gibson Discoverer Tremolo G8T schematic with the 6C4 tube? The only one I can find has a 12ax7, which mine doesn’t. Thanks Duane
Great sounding amp Brad.
Brad, I’m building an amp into an old Hilgen chassis, I’m basing my channel 2 on the Gibson GA20T channel two’s 5879 preamp, channel one is a 6G4 Princeton. My question is my channel two will not have a tremolo circuit, but will have the .005uf,/1mΩ tone shaping circuit. Will the lack of the tremolo and it’s tube have an effect on the function of the circuit?
Would you mind sharing the schematic for that? Sounds like the ultimate amp right there..
Nick McIntosh you would need to contact me, try Facebook messenger. Search me by name. It include middle initial “A”.
That R/C network is not needed if you don't have the tremolo. It's there to dampen tremolo "thump". You can replace it with a .02 coupling cap.
Maybe you could tell me what to look for .my bright channel.on my 59 twin don't work normal channel works fine.is there different tubes or caps that supply the different channels.
Could be a lot of things, but check preamp tube first.
I have a 1962 Ampeg reverb rocket virgin amp with a major problem hum and no vibrato. Should I replace all the tubes from vintage tube supply 80 or $90. 
Hum could come from a few different problems depending on the type of hum. It could be tube related, but it's most likely cap related. Does the hum persist whether the volume is up on the amp or not? Have your tried turning the amp on and pulling tubes out one by one starting with the first preamp tube? Try that. sometimes that can give you clues about where the problem is.
Ha! How come there aren’t tons of comments about brad getting cussed out getting edited out at the very end! Brilliant!
You can hear “really?? Turn it-“ hahaha
Floating converse shoe in the background doorway @24:45 haha
???????? But no one was in the house!!!!! :O
Nice sound!!
Beautiful!
Sounds great, but what is that Gretcsh combo behind it?
6159 Dual Bass. I have been modifying it any trying to increase the output and eliminate some noise. ongoing project.
The Guitologist Ah...I had a feeling it would be one of those 212 or 210 open-back "bass" combo amps from before they realized what they needed to do for it to work well with bass. Is that sort of a bassman copy?
Not a Bassman copy. There is a schematic for it online. Definitely Valco's own. I'm doing some mods on it right now because it's not as loud as I think it could or should be, and tehre's a lot of noise in the signal.
The Guitologist I have a random question. Is it normal to just always have noise when neither hand is touching the strings or the bridge on a tele? It's actually like very loud 60 cycle hum, and it goes away when I put hands on any metal part, so I don't really care that much, but does that technically mean my tele isn't grounded properly?
Yes, that's normal.
the covered ones on the right?
The first one, yes. The covered one closest to the edge of the amp.
What an amazing, rich, harmonic amplifier. Good grief.
Good sound I.g old amp.rich clean kinda like my 59 twin.
Reckoning is not hard at all. Just follow the directions in the recone kit to the letter.
I had the same amp looking like new out of the shop, that was until local repairman Miha Slapsak told me he "can't get replacement 6SQ7 tube" and gave me 20eur of material for "pro audio preamp" based on industrial British preamp. So amp stayed in thief's shop, preamp was not worth the effort because it was never meant for pro audio tasks.
That mahogany footswitch is probably a cutoff from a 60' Burst. Too bad its not worth as much!
Awesome
Playing reminds me of Neil young on the "dead man soundtrack "
noice!!!
Not all redwood has that straight grain ....I think the side you think is not redwood is in fact redwood! I have worked with redwood and that grain is found
Was hearing alot of feedback? maybe from the guitar pickups I guess...
Sitting on the floor right beside the amp, guitar is hollow body. Feedback isn't microphonic squeal though, it's musical feedback - the good kind! :D
These sound nice but don't do crystal cleans up loud .......like old fender amps.......I like a loud clean sound with zero breakup....
Someone could have rebuilt a broken footswitch out of wood?
tyvm every thing else is orig as far as I no except some of the 5881s have been replaced.
Glad they don't make guitars like that anymore. Nice amp though.