Gain/Drive without Volume Boost

[aziltz]

Has anyone found a way to simultaneously turn up gain or drive (for clipping) and turn down the output, keeping the overall volume level more or less constant?

I'm designing a slightly new kind of effect to share, and I'm thinking of a ganged pot, but i hesitate, because it seems like it might turn people off to the build.  Without giving too many details it involved an envelope detector and a feed-forward system, but i have reason to believe that Feedback would sound better.  But I need a signal after the clipping where the volume would not change with the drive knob.  Any thoughts?

[newfish]

Maybe put a Limiter on the output of your drive pedal.

That's my first guess anyway...

[aziltz]

Maybe put a Limiter on the output of your drive pedal.

That's my first guess anyway...

i jumped the gun when i started this thread.  sorry.

the idea is to put a limiter AFTER the clipping, but I want to use feedback instead of feedforward, so I need to reduce the gain as I increase the drive, before I do envelope detection.  i think I may have figured it out though.  Thanks

[Mark Hammer]

If I attempt something like that, I use the addition of a fixed resistor in front of the output volume pot.  Dual-ganged pots aren't THAT hard to find.  Alternatively, consider use of a DPDT toggle and a fixed gain change in conjunction with the added resistance.

F'rinstance, I have a CMOS overdrive based on the Anderton tube sound fuzz (the GP version not the EPFM version) with such a control.  The circuit sticks a non-inverting gain stage ahead of a two-invertor overdrive circuit akin the the Red Llama.  On mine, I have a "gain" switch that changes the ground leg of the op-amp front end and the resistance in front of the output volume pot such that while gain is added up front, level is subtracted at the exit point.  The simple way is to have two fixed resistors in series on the ground leg of the op-amp stage, and a fixed resistor in series with the volume pot input.  In position A, the switch shunts one of the ground leg resistors, thus increasing the gain.  In position B, the added resistor is "unshunted" (dropping the gain), but the switch now shunts the resistor in series with the volume pot, raising the level.

Works pretty nicely.  I flick the switch and get more "hair" on the signal without any terribly obvious volume change. Of course, the circuit itself has to be able to accommodate such a change.