WTB: tremolo module for reverberocket gs12r

[claytushaywood]

So I’ve tried everything I could to fix this guy and it’s just not happening. And the guy at fliptop amps store does not seem very hopeful about ever carrying the tm1 module replacement he used to have. Maybe if we get enough people together he will put some together. I wasn’t sure if it was because he couldn’t get parts or they were just expensive and/or rare. But I’d be willing to pay

Maybe soany of you have an extra or have a non functioning Ampeg with tremolo. I’m pretty sure most all of the 60s Ampeg’s with tremolo used the same optical module. I’d really appreciate it


I guess if this fails I could replace the speed and intensity pots with some modifications? Anyone have any ideas? Ive always thought the reverb was too bright on these amps and I couldn’t get as much bass as I wanted. Maybe put a tone control and dwell control on the reverb?

Or maybe just have a switch to add a cap to go from stock bright reverb to something a little darker?

Thanks for anything ya got for me! I’d love to get this tremolo working because this is such a killer amp

[claytushaywood]

Anyone? I severely miss the tremolo on this amp! I would pay good money!!!

[jjmt]

Anyone? I severely miss the tremolo on this amp! I would pay good money!!!

Yeah, it seems like the whole world is screwed by the loss of the only source of TM1 modules. I had posted this link:

http://music-electronics-forum.com/t34678/

in another part of this forum. Basically, it says rip the TM1 module apart and fix it. Not much to lose, I guess.

[claytushaywood]

Anyone? I severely miss the tremolo on this amp! I would pay good money!!!

Yeah, it seems like the whole world is screwed by the loss of the only source of TM1 modules. I had posted this link:

http://music-electronics-forum.com/t34678/

in another part of this forum. Basically, it says rip the TM1 module apart and fix it. Not much to lose, I guess.

Yeh Ive already tried that. it didnt work

[jjmt]

Hmmm. I thought I had posted a reply to this, but I guess I for got to actually post it. Sigh.

In any event, I guess what I would do in your case is try to build a bug. If you've had yours apart, you probably observed that it only has two parts (conjecture on my part): a lamp and a light-sensitive resistor. You can find the resistors at digikey:

https://www.digikey.com/products/en/sens...-cells/540

And the lamp, well, I don't know which one, but that link I shared in the previous post suggests that it might be an NE-2.

It seems like if you were to encase the lamp and the resistor in clear epoxy and cover the whole thing in shrink-wrap, you'd be in the ball-park. The only real challenge is choosing the right lamp and the right resistor.

Having looked at the schematic, if I've done the math right a light-sensitive resistor of about 1 meg (I think I saw that it might be a 1.3 meg) would work. The trick would be to get the lamp right. Too bright and it's going to be choppy, too weak and it will give a weak trem. And, of course, it needs to produce the right wavelength.

Honestly, I'm a bit more puzzled about the lamp part of the circuit. The word "neon" has been used, but I think the lamp has to smoothly transition from dark to bright, and that doesn't sound like neon to me.

Experimentation would be key. It just comes down to how into the project you are.

[jjmt]

I've become rather infatuated by this issue. As I've said, it is a common issue. I'm between projects at the moment, and am considering the notion of building a bug module. I think I've got sufficient stuff in my junk boxes to build a test chassis. I would have to order some parts for the device itself, but they are pretty cheap.

The thing is, I don't actually have an amp that uses a bug, so I would have no idea if it actually sounds right. Would you be willing to install an experimental device in your amp for testing purposes? No cost to you. I would just be doing it for fun. If successful, I would probably post a how to blog.

The caveat is that I have quite a bit of job-related travel over the next few months, so it would be hard to predict a timeline.

[claytushaywood]

I've become rather infatuated by this issue. As I've said, it is a common issue. I'm between projects at the moment, and am considering the notion of building a bug module. I think I've got sufficient stuff in my junk boxes to build a test chassis. I would have to order some parts for the device itself, but they are pretty cheap.

The thing is, I don't actually have an amp that uses a bug, so I would have no idea if it actually sounds right. Would you be willing to install an experimental device in your amp for testing purposes? No cost to you. I would just be doing it for fun. If successful, I would probably post a how to blog.

The caveat is that I have quite a bit of job-related travel over the next few months, so it would be hard to predict a timeline.

Yeh I could test them for you. You may want to ask the dude from fliptops about the logistics. Because he doesn’t believe that the right photoresistors are made anymore. The originals were like 10M off or some stupid high resistance. But I’m sure it could be altered or the rest of the circuit could be altered.

[jjmt]

The bug resistor and the 4meg pot are wired in parallel. According to the spreadsheet that I've put together that calculates the various resistance for various conditions of the pot and the resistor, I think I can use a 5 meg resistor (those seem to be available) and I doubt that you would be able to tell the difference.

In any event, I'll rummage through my stuff. If I can find the power transformer that I think I have to power the 12ax7, I'll start the process of assembling what I need to build the test rig.

[jjmt]

Just an update. I rummaged through the attic and found the transformer that I was thinking of. That was the hard part. I've got a Hammond enclosure and various odds and ends laying around. I've ordered $10 worth of parts, so I guess I am committed to moving this forward.

OP, you could help me out by posting the size dimensions of the bug and a description of how it mounts in the chassis. Pictures would be helpful.

[jjmt]

claytushaywood, I'm making pretty good progress on my end. If you could send me a private message with a mailing address, I hope to be able to mail you a trem bug for testing this weekend.