Switchable VTM 60/120

[clmowers]

Hello all,

Im looking to do the switchable 2 channel mod on either my VTM 60 or 120. Does anyone know where i can get a good set of instructions for this mod? I love the amp to death, just hate that its not switchable between the channels

Thanks

[PeanutNore]

I didn't realize it had multiple channels to switch between. Are you talking about making the functions controlled by the DIP switches able to be changed with a footswitch or something?

[Enzo]

It doesn't. The amp has a high gain input and a low gain input. On most amps that just means a couple jacks with resistors to make the difference. In this amp the high gain jack feeds into an extra gain stage, and the low gain feeds into the second stage. Switching contacts on the low gain jack assist. it can be wired for switching "channels" but it is not trivial to do.

[The Dude]

How about an A/B box?

[Enzo]

No, because when you plug anything into the low gain jack, the cutout contact breaks the path from the extra high gain stage.


Imagine if you used an AB box and plugged one into the amp input and the other into the amp FX return. The FX return would work, but the input would not because the FX jack breaks the path. This amp wworks the same way.

[The Dude]

Gotcha! I was not aware it was configured in such a way.

[Enzo]

Here, check it out

http://bmamps.com/Schematics/Peavey/Peavy_vtm_120.pdf

[The Dude]

Thanks for that, Enzo. Took me a minute to figure out. There's a lot going on there for just an input circuit.