Can y'all help me with a minor mod to a Peavey Rage 158?

[bclemons]

I want to mod this little amp to where the volume control for the clean channel is active when the distortion channel is on. If I'm looking at it right, only half of the op-amp is being used when the clean channel is selected. When the distortion channel is on, it looks to me that both halves of the op amp are used and the first stage is full on, bypassing the clean volume pot. Can I jump both terminals of the switch to ground to be able to use the clean volume pot to adjust the amount of signal going to the second stage of the op-amp?

PV Rage original 1987.pdf

[nickb]

I want to mod this little amp to where the volume control for the clean channel is active when the distortion channel is on. If I'm looking at it right, only half of the op-amp is being used when the clean channel is selected. When the distortion channel is on, it looks to me that both halves of the op amp are used and the first stage is full on, bypassing the clean volume pot. Can I jump both terminals of the switch to ground to be able to use the clean volume pot to adjust the amount of signal going to the second stage of the op-amp?

[ATTACH=CONFIG]37208[/ATTACH]

Both halves are always used but the gains of each are very different in the stages between the two modes. You are right that shorting the switch S!B will enable the clean volume but the problem is the gain of the first stage will be much greater (approx x10) and I suspect that is not want you want or will even like.

If you just want to reduce the input to the second half you will get the effect you desire without any mods just by backing down the volume of your guitar.

[Enzo]

If you want to tack the wiper of the clean volume to ground directly, then the control will stay live. It won't hurt anything, so feel free to try it. The switch will still control the tone bypass cap for fatness that way. If you like it, fine, if you don't, remove the ground you just placed.

[bclemons]

Well, I tried it and didn't like it. I did take the resistor on the headphone jack out so I can use it as a speaker out.

[Enzo]

Assuming you replaced the resistor with a wire. If you simply removed the resistor, the jack would go dead.

But be careful, the existing internal speaker is already 3.2 ohms, If you plug an 8 ohm speaker in, that makes a total load for the amp of 2.3 ohms, pretty low. And if you dare plug in a 4 ohm speaker, then the result is only 1.8 ohms. In other words, the existing speaker is pretty much a full load.

[bclemons]

Yes, I jumped the resistor. The headphone jack cuts the internal speaker on this amp.