Two distortions, one box

[shawsofhell]

Hi i want to build a distortion pedal with two different distortions in it. I'm not after fuzzy distortion sounds more like an overdriven amp. I want it to have one distortion which is really mild that only breaks up a little bit at full gain and the other distortion to be like a full on lead channel. I was thinking of using the runnoffgroove thunderchief as the lead sound (any comments) but don't have any idea abot the other channel.

Any suggestions would be appreciated!!!!

[RDV]

The Double D at Runoff Groove fits that bill to a T.

Regards

RDV

[Mark Hammer]

In my 4049-based CMOS "tube-sound fuzz", I did the following, which may interest you.

The "head" is a simple non-inverting op-amp stage that drives a pair of invertor sections.  A pot on the output of the op-amp sets how hard the CMOS invertors are being driven; a sort of sensitivity control.

Of course the gain of that first stage depends on the feedback resistor and resistor to ground.  What I did was put a pair of small-value resistors in series on the ground path.  Between their combined resistances, the gain is set to 20 or something like that.  With one of them shunted, the gain switches to 50 or thereabouts.  I wired up a DPDT switch that a)  switches between gain settings by shunting one of the resistors, and b) switches between output-level settings by shunting a fixed resistor in series with the volume control.  In essence, it switches between two different gain/master combinations, yielding a signal with more "hair" on it, but the same loudness.

Obviously, you don't have to do the same thing, but it may well be possible to have two versions of the same circuit enabled by a footswitch, with more and less "hair" on them.  Certainly one of the advantages of this arrangement is that you don't have two effects circuits "on" all the time and draining the battery at twice the rate.  Another advantage is that you don't have to worry about stray signals and oscillations produced by having two high-gain circuits in close proximity to each other.

A second strategy is simply to stick a switchable one-transistor clean boost-stage ahead of your overdrive.  Even a simple x3 or x5 gain stage can turn a timid overdrive into a torrid beast.  Of course the advantage is that you also have a clean boost at your disposal.  If you want to get *really* sexy about it, you can use that stage as an active splitter and tap off a second output after the booster to feed elsewhere.