Can someone explain TM-1 Tremolo Module?

[Opry Audio]

Hello! As my next build I'm thinking about doing a GA-5 based amp with tremolo. I really love how unique the tremolo circuit sounds in ampegs, but what makes it sound so dope? Also looking to mimic the choppy goodness mode on the intensity knob. But what makes the TM-1 different than a fender roach LDR? I've heard you can't replace a TM-1 with a fender LDR so they must be different in some way besides one being in a metal box. Is the same circuit and sound achievable with a regular (and way cheaper) LDR?

So, looking for some info on the module and the tremolo circuit in general.. like what's going on with that awesome intensity switch??

Here's a schematic with the relevant trem circuit

https://ampeg.com/support/files/Schematics/G%20Series/GS-12R%20(Reverb%20Rocket%202)/GS-12R%20Schematics%202.pdf

[jjasilli]

https://music-electronics-forum.com/showthread.php?t=12139

[PRR]

Fender shorts the signal from a resistance to ground. Ampeg opens the signal to the tone stack. These should be significantly different on the ear.

[kagliostro]

Guessing ... considering that the TM-1 photoresistor is in parallel with a 4M pot

which will be a reasonable value for the photoresistor ? (a start point for a future experimentation)

Franco

[Opry Audio]

Thanks for the replies y’all. That’s a good link. I get what’s going on with this now. It took me a bit to see that the trem circuit is introduced into the tonestack by X and Y voltages. Gonna try to build this into a Bassman with 6V6’s, TM-1 trem circuit, and CF vox tonestack