Can you identify this mystery amp?

[evancorylevine]

This broken amp was gifted to me with the explanation: "somebody built this amp at home and it has been deemed by technicians to be a mystery and a mess not worthy of investigation or repair"

Now I'm thinking I'd love to build something into this chassis. I've been desperately wanting a princeton reverb. I realize that this is probably a much more powerful amp, but I'll take what I can get if I can build something with similar functionality into this chassis.

What is this? What are my options?

Gallery here: https://www.dropbox.com/sh/fhfyxtulorhx7lw/AAAfbKpLp4I4kO9AWLAMBl2ta?dl=0

[shooter]

What is this? What are my options?

no clue what it is except LOUD.  It's winter, take the time, draw it out, fix it, then mod it.
the tubes & iron are well worth the price of lugging it home. without a schematic I'd guess 50 - 80W if it's fixed bias, 30 - 50W self biased

[sluckey]

This broken amp was gifted to me with the explanation: "somebody built this amp at home and it has been deemed by technicians to be a mystery and a mess not worthy of investigation or repair"

That's pure BS.

I would guess it's a single channel Twin Reverb. Definitely worth fixing, even if you have to rip out the guts and drop a Hoffman single channel AB763 board in it. I would not try to convert it to a PR.

[evancorylevine]

I would guess it's a single channel Twin Reverb. Definitely worth fixing, even if you have to rip out the guts and drop a Hoffman single channel AB763 board in it. I would not try to convert it to a PR.

oh my gosh that would be so deeply dreamy. I'm so excited to give it a shot!

[sluckey]

Let's see some gut shots.

[evancorylevine]

Let's see some gut shots.

I just added them to the album!

https://www.dropbox.com/sh/fhfyxtulorhx7lw/AAAfbKpLp4I4kO9AWLAMBl2ta?dl=0

I can't wait to hear what you all think.

[sluckey]

It's definitely a Fender AB763. Not sure what kind of tremolo (if any) circuit. It's worth fixing just as it is.

[evancorylevine]

Would it be reasonable to rebuild it as an AB763 with a PR trem? I'm really here for the trem.

[sluckey]

Would it be reasonable to rebuild it as an AB763 with a PR trem? I'm really here for the trem.

The PR trem circuit is a little too light weight for four 6L6s. But if you rebuild with a Hoffman single channel AB675 board, you'll have a better trem circuit.

I highly recommend you plug the amp in, evaluate as is, fixing any issues. IOW, have a solid working amp before you start ripping it apart.

[2deaf]

it has been deemed by technicians to be a mystery and a mess not worthy of investigation or repair

Did they offer to haul it away and dispose of it properly, also?

That's one nice score, there.  Even if all the parts were in a bucket, it would still be a nice score.  You know what it would cost to buy all those parts?

There is no tremolo in this amp.  That extra knob changes the resistance from the reverb recovery grid to ground.  I don't know why.  You would have to add another tube or go SS to get tremolo in that amp.

Everything looks good inside.  What's wrong with it right now?

Can you post a picture of the doghouse capacitors?

[Joel]

If you do get it working, but don't have room for a tube tremolo circuit, here is one from this forum that I've been wanting to try out.  It should be fairly easy to mod in.  It's a LND150 Mosfet tremolo which is very similar to the Hoffman tube driven one (as offered in the Hoffman version of AB763)

Unfortunately I don't remember which thread it was, so whoever created this circuit - thanks!

[evancorylevine]

Would it be reasonable to rebuild it as an AB763 with a PR trem? I'm really here for the trem.

The PR trem circuit is a little too light weight for four 6L6s. But if you rebuild with a Hoffman single channel AB675 board, you'll have a better trem circuit.

I highly recommend you plug the amp in, evaluate as is, fixing any issues. IOW, have a solid working amp before you start ripping it apart.

What's an AB675? Did you mistype? I couldn't find any such thing on the internet. Apparently, I'd have to add another tube to get an AB763 trem in there. that's not out of the realm of possibility for me. I can't do anything on this thing right now, but I do look forward to hearing what all I should be doing with this thing. I'll probably plug it in through a current limiting bulb when I get the chance.

it has been deemed by technicians to be a mystery and a mess not worthy of investigation or repair

Did they offer to haul it away and dispose of it properly, also?

That's one nice score, there.  Even if all the parts were in a bucket, it would still be a nice score.  You know what it would cost to buy all those parts?

There is no tremolo in this amp.  That extra knob changes the resistance from the reverb recovery grid to ground.  I don't know why.  You would have to add another tube or go SS to get tremolo in that amp.

Everything looks good inside.  What's wrong with it right now?

Can you post a picture of the doghouse capacitors?

I'll get you those pics as soon as I can!

Bummed about the tremolo, though an outboard one seems just as well, right? I may very well add that tube and redo the board if this thing isn't an easy or reliable fix.

[sluckey]

mistyped