My Tremolo TMB Reverb project

[JohnJankowski]

I’ve successfully built a dozen or so amps to date, but this is my first using a blank chassis. Layout, drilling and cutting has been an education. It’s not perfect, as I have a few extra holes in the front, but it is coming together nicely. I’ll post more photos and updates as things move along.

Although not photographed, I have a top mount transformer made to spec by “Musical Matt”. Matt is based in Tennessee and sells through eBay. I’ve used many of his transformers and chokes in the past and he was able to special-build the power transformer. He made two. As far as I know, the other is still available.

I do plan on designing a front face plate. As for the rear, if anything at all, I’ll just lay out something that starts 1/2 inch left from the left RCA reverb tank jack, to 1/2 inch right of the right side effects loop Cliff jack.

I’ve already had invaluable help from Josh on this project. As well as on the TMB Classic “Lite” I built a few months ago.

[JMPGuitars]

Looks like a nice start.

Are you gonna add switches for the tremolo? Or footswitch only? That extra cap for speed range won't engage without a switch or a jumper.

[JohnJankowski]

Actually, no. I’ve put the extra cap in as I suspect I’ll want to slow the tremolo down anyway. I’ve also (since the photo was taken) installed a jumper at the switch point. Once the tremolo is working, I’ll try with and without that jumper, select one speed option, then leave it there.

[Bieworm]

I'm jealous of you. You are gonna experience this amp for the 1st time. I've built quite a few of these. But there ain't nothing like the feeling you get switching this on the 1st time. You're in for a big treat!
My version is a little different on the gain control. My settings are G5.5 V3 T6 B6 M8. In your case you'd have to dial the gain to 8 or 9. With these settings and a guitar volume pot you can get everywhere
Here's my video of the prototype, the very first Tremolo TMB ever https://youtu.be/DJde9deFb0M

[JohnJankowski]

That is a fine looking amp!

I am already considering a 36watt version of this upon completion of this one. I don’t know if I’ll go with a combo or head. I’ve tended towards head units as I have a cabinet housing a 12” original JBL that sounds great with any amp I connect to it.

However, yours sounds and looks terrific.

[JohnJankowski]

Transformers in place

[JohnJankowski]

More progress. Faceplate installed. Power section wired.

[JMPGuitars]

Nice! Where'd you get the faceplate?

[JohnJankowski]

Nice! Where'd you get the faceplate?

I laid out the design and sent it to Mojotone. I’ve worked with them on other projects.

[Bieworm]

Just a word of advice. Look closely at the layout where to use shielded wires. Don’t forget the plate wires on V1, or you’re in for trouble

[JohnJankowski]

Just a word of advice. Look closely at the layout where to use shielded wires. Don’t forget the plate wires on V1, or you’re in for trouble

thanks. I’ll be sure to pay attention to those details.

[JohnJankowski]

Just a word of advice. Look closely at the layout where to use shielded wires. Don’t forget the plate wires on V1, or you’re in for trouble

[Davidscott]

I am a bit confused here. Bieworm wrote: that you should have shielded wires on the plates of V1, and showed a wiring layout of it. But I do not see any shielded wires on the signal path inputs to pins 2 and 7! which is critical!
what am I missing here?

[JMPGuitars]

what am I missing here?

The part where it says shielded wire.

[Bieworm]

Pin 2 is the input from the jack, and says shielded on the layout. Pin 7 is the input of the tremolo oscillator. I have a shielded wire there too. But that’s optional I guess.

IMG_8625.jpeg

[Davidscott]

I just never had heard of shielding the power line going to pins 1 and 6 before, and I have never seen it on any amps. Or did you mean the signal path that goes from pin 1 through cap and into the next stage (pin 7) of the V1B? so this is why I was confused. because you stated "you’re in for trouble" if they are not shielded. what do you mean? as in there will be excessive 60hz noise? please explain.

[Bieworm]

I just never had heard of shielding the power line going to pins 1 and 6 before, and I have never seen it on any amps. Or did you mean the signal path that goes from pin 1 through cap and into the next stage (pin 7) of the V1B? so this is why I was confused. because you stated "you’re in for trouble" if they are not shielded. what do you mean? as in there will be excessive 60hz noise? please explain.

There just is a chance for squeal and oscillation when those DC supply wires aren’t shielded. One time I forgot to use shielded wires there and ‘kaboom!’ …Oscillation!

[JMPGuitars]

I just never had heard of shielding the power line going to pins 1 and 6 before, and I have never seen it on any amps. Or did you mean the signal path that goes from pin 1 through cap and into the next stage (pin 7) of the V1B? so this is why I was confused. because you stated "you’re in for trouble" if they are not shielded. what do you mean? as in there will be excessive 60hz noise? please explain.

Power Lines? Plate wires carry signal too. Review the schematic and figure out where the audio signal goes.

[Davidscott]

"Power Lines?"
sorry, I meant DC voltage going to the plates of the 12AX7. My bad, for not using the correct terminology.
I'll shut up now.

[JMPGuitars]

"Power Lines?"
sorry, I meant DC voltage going to the plates of the 12AX7. My bad, for not using the correct terminology.
I'll shut up now.

No worries, all of us learn stuff here (myself included). Yes, DC voltage goes to the plates. Also AC signal passes through there. Trace the signal path on your schematic and see why shielded wires were added here.

I've never made a tremolo circuit without those shielded wires, and I've also never had a tremolo circuit fail. Correlation yes, but avoiding noise and oscillations are a good thing too.