WTF is going on inside of my Peavey Bandit Preamp?

Help!I'maRock!

Help!I'maRock!

Mediocringly Derivative
From what I can tell, the Saturation knob adds compression to the distortion generated by the preamp. This takes a relatively grating fuzz tone, and turns it into a relatively flabby distortion. But at low gain settings, it works really well. And on bass, it's fantastic.

Here's the schematic:
bandit65.jpg


So what's the deal? And how can I turn this into a pedal with a blend knob?
 
Help!I'maRock! said:
In pedal format, I would add the blend. Could you please tell me more about the saturation knob and what it actually does?
Click to expand...

It is controlling the gain into the clipping section (two diodes). Increasing the pot increases the saturation (distortion). Can't see the direction arrows on the ganged pots but they may be wired such that as the clipping goes up, the clean mix is reduced. This is where your compression is happening and as you lose the dynamics of the original signal.
 
Output is at the bottom where the FET switching ckt was. Circuit as is has no tone controls much like the MXR Distortion +. Volume pot would be on the output if desired. Just remember to add a .01 ufd cap for the output. You can eliminate things like the -15/+15v diodes too. The interesting part is that the circuit probably operates on -15/+15v which gives more headroom on the op-amp. Start with this on a bread board.


upload_2014-12-31_11-16-27.png
 
Modern Saint said:
Output is at the bottom where the FET switching ckt was. Circuit as is has no tone controls much like the MXR Distortion +. Volume pot would be on the output if desired. Just remember to add a .01 ufd cap for the output. You can eliminate things like the -15/+15v diodes too. The interesting part is that the circuit probably operates on -15/+15v which gives more headroom on the op-amp. Start with this on a bread board.


View attachment 17897
Click to expand...

What's your rate?
 
You must log in or register to reply here.
Back
Top