From juicy fuzz to crystal clean?

[rackham]

Hey guys

I'm working on a multi-mode filter circuit and I could do with some suggestions for a fuzz/distortion/boost to stick in front of it.

I want the facility to add some extra harmonic content before the filter to accentuate it and generally liven things up a bit if required.

I'm after something with as low a part count as possible too, I've been experimenting with the Electra distortion circuit and I've got some really good sounds out of it but due to the clipping diodes I've not managed to clean it right up, even using dual ganged pots.

So what I need is a decent fuzz with seperate level and fuzz controls that will clean up completely, as I'd rather not stick any more switches on the thing than I already have (for the filter stuff).

Any suggestions gratefully received.

Cheers

Jon.

[vortex]

Check out the Roger Mayer Axis Fuzz. From what you are describing , I think it fits the bill.
The Axis is a bit more complicated than an Electra but I doubt that you would be satisfied with a one tranny circuit.

Any way, that's my two cents...

[rackham]

Cheers Vortex.

I messed with the gain and different diode combos on the Electra and got some surprisingly good results as far as fuzz is concerned, the only problem was getting it to shut up and behave itself too .

I'll check out the Axis, I've been looking for an excuse to build one for a while

[rackham]

Hmm, I've been checking out the Axis and I think it might be a bit splatty (judging by the demos I've heard) for what I'm after.

Any other suggestions?

[earthtonesaudio]

You could stick a version of an AMZ "warp" control on the diodes of the Electra distortion...

Normally you have the back to back diodes to ground, and after them there's some resistance to ground (such as a volume pot).
You could take a large value pot (maybe 1M) to ground, after the diodes, and instead of connecting the diodes to ground, put them on the wiper of the pot.  That way, when the wiper is at the top (signal end), the diodes are shorted out of the circuit, and when it's at the bottom, they're back to ground again.  Using a large value pot keeps it from messing with the volume pot too much.

[ambulancevoice]

maybe something like this?

[earthtonesaudio]

Based on this schem:



I have a weird idea using a dual ganged pot:

Replace the 2.2M feedback resistor with 1/2 of the dual pot.  Lugs 1 and 3 go where the 2.2M resistor is now.  Connect lug 2 to one of the either lugs (wired as a rheostat, but you're still going to use lug 2).  Then break the connection between collector and output cap, and wire the wiper to the output cap.  The other half of the pot will be in parallel with the diodes, but lift the diodes' ground connection and connect it to the wiper.  You should wire it so that as the diodes get shorted out of the signal path, the gain is decreased.  This would make up for the volume increase you'd otherwise get from removing the diodes. 

Oh yeah, and put a fixed resistor in the feedback loop so that there's always some amount of gain...

If you count the dual pot as "one" part, the only additional component you will need is the extra resistor for setting the minimum gain.

I have no idea if it would work, but it seems like it should in my head.  Let me know if you would like a picture, I can draw one later.

[rackham]

Cheers Alex, that's definitely something for me to have a go at.

I've got a few dual pots with breadboard wires attached, so I'll give it a go and report back my findings.

Once I've figured out how to bias a multi-opamp filter schem I found earlier...

Jon.