More Drive out of a footpedal

[Andy]

I built the El Griton from Tonepad.com and was wondering if simply swapping out the 500K drive pot for a 1meg will give me more drive or will I need to adjust a resistor or capacitor?

Any help is greatly received.

http://www.tonepad.com/getFile.asp?id=1

In general, what will give me more "grind"?

[Marcos - Munky]

http://www.guitarkit.com/distortion/GeneralHotrodding.html
You will find some mods in this site.

[Mark Hammer]

"Drive" or volume?  Given the output limiting properties of the clipping diodes, sticking a 1M resistor in there will only give you more fuzz, and not much more volume at all.  Moreover, you would lose the TS-9/808 tone.

Worth noting thatthis is not really the pedal for producing gobs of gain to overdrive an amp.  It is intended to push the amp a *little* harder with a preshaped tone.  If you need more output, I suggest you tack a booster stage after it, either in the form of another pedal, or in the form of an additional transistor or op-amp stage in the pedal itself.

Alternatively, if the purist tone doesn't matter all that much to you, feel free to stick in a 1M pot, but add a 4th silicon diode so that the clipping pair is now a dual pair: two series diodes in one direction, two series diodes in the other direction.  This will raise the clipping threshold so that as you crank the gain you won't get hard fuzz until you turn way up.  This will have the effect of providing more audible output.  If you are using the El Griton board, you already have space for 2 diodes in the one direction.  For the other pair, simply solder two 1N914s end to end, bend 'em over, and solder them into the board as you would a single diode.

[Ed G.]

I think the 'drive' he is looking for is fuzz, sustain, saturation, etc. Increasing the resistance in a negative feedback loop will increase this, but not necessarily the output gain, as Mark noted.
Increasing the resistance in the feedback loop is how the fulltone fulldrive pedal switches in its 'boost' channel, it just switches in an additional pot for more drive and sustain.

[Andy]

Yeah, I wanted to give the distortion more "bite".  I replaced the 500K dirve pot witha 1 m linear.  I changed the 51K series resistor from that to a 180K (just picked something higher)

It sounds more eighties now.  I like it.  I assumed the feedback loop is the part of the circuit that runs from the output of the op amp and connects to the drive pot?  I figured that if I changed the resistance, I should get more "oomph"

Does changing small things like this constitute the right to rename a pedal and call it your own?  Or does it give you the right to say the design is yours?

[amz-fx]

If you reduce the value of the 0.22uF tantalum after IC1a, it will open up the sound somewhat...  try a 0.1uF mylar and see if it is a change that you like.

regards, Jack

[Ed G.]

Does changing small things like this constitute the right to rename a pedal and call it your own?  Or does it give you the right to say the design is yours?

Give you the right??? I won't comment on the ethics of all this. But, it's been done. There's about only a jillion tube screamer clones out there with small tweaks.