Splitting a wave and fuzzing the different halves

[tcobretti]

http://www.schumannelectronics.com/two_face.html

I put this in the Members section and didn't get much help, so I figured I'd put it out here.

What I thinking about is a workalike. I suspect Schumann has a background in analog synths, so I'm pretty sure he used some ICs to make it happen (especially because of the fact that his circuit is 12v bipolar), but would it be possible to make a simple AB booster and the run the top into one Ge FF and the Bottom into another?  Would it be cool?

[Gus]

Not sure what the words at that site mean. 

This is a guess

  +- supply, + a NPN FF and - PNP FF?  Two FFs and opamps maybe because of the split supply?

I would GUESS the sens is a FF type gain control

  Input to gain buffer then two series resistors splitting the signal one end of each connected to the buffer the other ends to each FF type,this would do two things, allow the signal to be split and sent to two FF types because of the input R of a FF type and also work with the guitar and feedback resistor to set the first transistors stage gains:  HOWEVER the Drive might be a buffer gain stage, guitar to gain stage, output of gain stage to resistors in series with the inputs of the two FF circuit?s

Boost, I would guess another gain pot in parallel with the sens pot, boost switch switching it in?

Level, I would guess output volume control. 

Clean, maybe a mix pot when linked?

OR the sens pots can be series input resistance to the FF types and the FF types have a fixed resistor gain that the boost switch parallels the boost pots with

Or maybe the clean is a dual pot used to set the min gain of each ff type and the boost pots get switched in cap coupled etc.  Passive mixing of the level pots or opamp mixing?

All of the above are guesses from reading the words and looking at the picture

Split is two out no mixing I would guess

[caress]

i think if you split the signal, then changed the offset of each and seperately fuzzed them, you might have decent results...?

[Paul Perry (Frostwave)]

I don't think there is much point to separately fuzzing the two halves.
Because, when you recombine the signals, you just get something that could just as easily be done by asymetrically fuzzing the original signal.
Or, just fuzzing it as per normal.

Incidentally, I don't sub to the "members section".
I could be wrong, but I can't see the point - if it is intended to enable people to discuss inventions that they think mightg et ripped off somehow, it's pointless, because the only secret is the one you tell NOBODY.

[tcobretti]

Ok, Paul I see what you are saying.  Is there a way to control the symetricality of the fuzz - i.e. add a knob that changes how symmetrical it is?

[The Tone God]

I'm just working off memory but didn't Peavey's "TransTube" circuit work by clipping each portion of the signal in different steps ? Might be something to look in to.

Andrew

[gez]

Incidentally, I don't sub to the "members section".
I could be wrong, but I can't see the point - if it is intended to enable people to discuss inventions that they think mightg et ripped off somehow, it's pointless, because the only secret is the one you tell NOBODY.

I appreciate your point of view, Paul, but as I've said before I quite like the members section.  I agree, you'd be an idiot to think/pretend that it prevented someone from ripping-off your ideas, but I like to think that anything I post there is shared amongst people who are more likely to contribute to this forum and put something back in.  I don't know, it just seems friendlier.

[Paul Perry (Frostwave)]

  Is there a way to control the symmetry of the fuzz - i.e. add a knob that changes how symmetrical it is?

I would think that you could do that by altering the bias on one or other of the transistors.
But now I have been forced to think about it, maybe splitting the signal & having two fuzzes IS worth exploring.
Because, it's certainly going to sound different - the normal fuzz is usually very asymmetric anyway. With the two halves of the signal being fuzzed by circuits that are mirror images of each other, you get a symmetric output (if the circuits behave the same, which will be difficult to guarantee.)
The harmonics will be different with the split system. If balanced, maybe you will get only even harmonics.

Another of those questions that look obvious at first - but when you look closer...! Thanks for bringing it up.

[Gus]

I wrote out some ideas are you going to build something?

"would it be cool"   Build something and find out.

The tricker part will be the output mixing.  Design for a Ic (collector current) and output R in the FF types.

[caress]

it might be worth exploring effecting the split with other effects as well... phasing each half, for example...?  might be interesting.

[puretube]

http://www.diystompboxes.com/smfforum/index.php?topic=47052.0

[Gus]

Been done Read about the biphase and the quadrafuzz

Now do people read others post or just post?  I read the whole thread before I post and give credit when I post the same thing as a person above me in the thread.

I have not seen that two fuzz thing but have you ever clipped a FF type and looked at it on a scope? Take a 10K(crude sim) and drive the FF from a signal generator.  Look at the duty cycle or mark to space or what ever you want to call it.

[tcobretti]

Paul - One question I have is whether crossover distortion would be an issue.  It seems like you might get some very nasty clipping, but I guess the fuzz might cover that up.

Gus - I am not real smart at this stuff.  I don't own a scope and haven't seen any pedal thru one.  The only way I would know to try it would be transistor based.  After a bit study I'd say possibly setup a single transistor as a phase splitter (much like an octave fuzz) then half wave rectify each side to eliminate the bottom half of the wave.  Then run each into a fuzz and play Purple Haze.  But I don't even know - can you rectify an audio signal?  It's not really AC, but it is alternating, right?  I also figured I'd ask because it seemed like an interesting idea that I would lack the know-how to execute.  I figured one or a few ICs would be part of the solution, and I know less about them than transistors.

See, I know very little.

[DavidRavenMoon]

Been done Read about the biphase and the quadrafuzz

Well actually the Mutron Bi-Phase was two separate phase shifters that could be used in either parallel or series, and the Quadrafuzz is basically a 4 band EQ with fuzz on each band.

Neither of those effect the positive or negative halves of a waveform.

[Gus]

The reply was for caress's posts.  Series parallel phasing. and splitting the signal and fuzzing.

Read my first post carefully.  There are a few ideas on how to do this
My third one has a hint about waveform shape.  Clip a FF and look at it on a scope then change the operating points and look again.  The input of a FF being a NOT SO GOOD  transresistance amp requires you sim the guitar/bass RCL mess if you want to test the FF type correctly: However a series resistor is close enough for this test IMO.

If you are mixing two of the SAME waves  non invereted  they add if you are mixing them inverted they cancel.  Now if the waves are shaped a bit different the mixing will be different.