Two distortions in parallel

[gutsofgold]

Can this be done? As simple as splitting the input into each effect and then joining both outputs into one? I'd imagine this would sound nicer than cascading distortion in series.

[RonaldB]

I tried that, works fine, The sparkle drive is also based on this technique. Maybe you need to buffer both circuits.
Good luck.

[GibsonGM]

I'm working on one now...using the AMZ A/B/Y splitter at the front end, and a simple op amp audio mixer at the other (Google for that, it's a simple circuit).  That adds the buffering.  Plus, I can switch out the ABY to use my talkbox with another amp.
Best make sure the signals are in phase going into the mixer tho, or it will sound weird!

[Mark Hammer]

Can this be done? As simple as splitting the input into each effect and then joining both outputs into one? I'd imagine this would sound nicer than cascading distortion in series.

I did both of these with the "Roseyray" ( http://hammer.ampage.org/?cmd=lt&xid=&fid=&ex=&pg=3 ).  That is, I cascaded two clipping sections, but tapped the point between them so that I could pan between a milder distortion (think Dist+ but much warmer) and a more intense scooped distortion.  The schematic shown on my site is an earlier one.  It ran into oscillation problems stemming from the fact that the panning "Tone" pot also presented a path for the 2nd stage output to feed back to the stage 2 input.  Strategic placement of some caps helped to alleviate that.  I'd show you how, but I can't access the schematic on photobucket.

In any event, you needn't copy it.  The point is that blending two parallel or even cascaded distortions CAN work, and produce some nice sounds.  The one caveat I would draw your attention to is that the two fuzzes/distortions really need to be VERY different from each other in order for such an arrangement to provide any added value.  Clean+distortion (à la Sparkle-Drive) works nicely because clean and distorted are already very different from each other.  You need to maintain a similarly high contrast between two signal sources in order for their blending to be pleasing.  I tried to do that in the case of the Roseyray with a treble-filtered moderate clipping stage and a searing double-clipped (and scooped) second stage.

[Paul Perry (Frostwave)]

It would be well worth while putting a phase reversal section in as well, after one of the fuzz sections. (Arrange it so it can be switched in or out).
That way, you have the option of cancelling out some or all of the fundamental, giving a much wider range of effect.
Note if you do this, you might want extra boost at the output, to make up signal loss thru phase cancellation.

[runmikeyrun]

i was thinking of this a while back for bass.  How do you assure you're not inverting the signal?  I know it's obvious with opamps, but what about with transistors?  I have a BMP that would benefit from this type of thing.

[WGTP]

http://www.freeinfosociety.com/electronics/schemview.php?id=163

Check out the BOSS OS-2.  It has 2 separate overdrive/distortion-EQ sections in parallel that are blendable.  Interesting mixing circuit.  The overdrive is similar to the SD-1 (diodes in feedback loop/asymmetrical) with lots of mid's and the distortion is similar to the DS-1 (diodes to ground/symmetrical - Rat like) with a mid scoop.  The EQ difference adds to the distinct character of each (as Mark suggested).  The Blend knob also acts as a mid-range control because of the EQ difference between the 2 sections.  Mods for the SD-1 and DS-1 should work (more or less) for each.  The overall Tone control is like the SD-1.  As with other BOSS pedals, it could be simplified by omitting some of the buffering/switching circuitry.   

http://www.aronnelson.com/gallery/main.php/v/WGTP/Boss_OS_2_Mods.gif.html?g2_imageViewsIndex=1

[WGTP]

It occurs to me that something like a Fuzz Face could be subbed in place of one of the op amp distortions in the BOSS OS-2 as long as the volume is matched so that the balance isn't messed up.   

[Paul Perry (Frostwave)]

How do you assure you're not inverting the signal?  I know it's obvious with opamps, but what about with transistors? 

There are only two transistor configurations that are commonly seen:
1.The emitter follower, (or "common collector") which is a buffer with no gain, the input is to base & the output is from emitter.
This does not invert.
2. The "common emitter" amplifier. Signal to base, output from collector.
This has gain, and inverts the signal.