The BMF Fuzz, will this work?

[billings]

I think that he's talking about the FET version, but his remarks on reducing the volume coming out of the Q1 stage apply to all of them. 

I think the second knob needs to go.  It's killing the simplicity of the 1-knob design without really adding much control. 

If a unity gain clean signal with the knob all the way on the clean side is the goal, then R6 can be replaced with a 100k resistor to ground and (unless I'm mistaken) R4 can be replaced by a 10k resistor to make Q2 a unity gain inverting amplifier.  I can't remember if the biasing will need to change as well if you do that, though.  The example I see in art of electronics puts bias at 1/3Vcc, so my educated guess is 150k for R2.

All of the suggestions for the clean channel so far have been suggesting discrete transistor buffers.  If you're going to invert with those, though, all of these solutions limit you to signal swings of less than 4.5V.  An inverting op amp wouldn't have that problem.

[Dragonfly]

heres one i designed a couple years ago...it might inspire some new ideas for you...

http://aronnelson.com/gallery/Dragonfly-FX-Schematics-%21/SIX_SHOOTER

AC

[billings]

Correction - only the configuration with identical emitter and collector resistors would be limited to 1/2 Vcc, but the others would definitely distort at some point.

[petemoore]

I think the second knob needs to go.  It's killing the simplicity of the 1-knob design without really adding much control.
  If you're talking about the Pot I suggested, I suggested it as a way to find the fixed resistor values for a fixed divider, to bring the output of the Bazz Circuit down to or closer to equaling the output of the 'bottom' circuits suggested, Jfet or BJT, so that the mix knob has a chance to 'mix.
  Use the pot only to find the setting which allows the mix control to work the way you think it should or what you like, then pull the pot and install fixed resistors to mimic that setting, values that ~match measurements of the undisturbed pots setting, between wiper and lug 1, and wiper and lug 3, make sure wiper to lug 1 *resistor [the fixed one] goes in the same place you had the wiper and lug 1 connected.
  You're still at 1 pot, but the mix knob should work better with both mixed circuits being near equal...course you might want 60/40 or...whatever the 'extra [only for testing settings to choose the fixed divider resistors values] pot's' setting sounds good at.

[vanessa]

Your totally right Pete, that's why I left the R6 pot in there. I figured you would want to set the circuit to unity gain. I did not think of putting a fixed resistor (I figured that people would just put a trimpot in there) but I think I'll add that option in the PCB as that is a great idea.

[petemoore]

R6 is on the 'bottom'...the jfet or BJT is already going to be 'behind' in the gain dept, adding a pot here will reduce it's output even more.
  I would connect C4 back to R7, and 'splice' R6 to C3, wiper to R7, ground the last lug....IOW exactly the way it's shown, except placed to attenuate the 'top' circuit, not the bottom one.

[vanessa]

I see what you are saying Pete, call me crazy but I have built the Bazz Fuss before and I did not think the output volume/gain was that crazy. I know this seems nuts comparing a darlington to a single BJT circuit but I think the LBP would overtake the Bazz Fuss circuit and be the one that needs attenuating. I think it may have something to do with that diode clipping the circuit (bazz fuss).
When I built the bazz fuss I tried several transistors and darlington pairs. I did not find the darlington to really boost the signal that much at all, than make the circuit sound more defind, almost compressed in a way.
So when I look at this circuit (bazz fuss) I picture it like I would if it had just a single NPN transistor, then knowing that the diode clips the signal on top of that.

[petemoore]

When I built the bazz fuss I tried several transistors and darlington pairs. I did not find the darlington to really boost the signal that much at all, than make the circuit sound more defind, almost compressed in a way.
  Shoot I forget how much this thing puts out now, I kinda went to Whisker Biscuit..I even forget which Bazzes I Fuzzed out on...
  I'd just introduce a resistance between SP and Gnd. wherever you decide to, quick test'd be connect a pots wiper to testclip, and an outside lug to testclip, clip to ground, other clip to signal path, at one side of the 10k or the other, adjust as necessary.

[Meanderthal]

 That makes sense vanessa- you may have a point about that clipping diode acting as a limiter. I can picture it just clipping harder as the volume increases... squaring off the waveform at the same level no matter what. And, you're right about the lpb being a powerful booster. But is it THAT powerful? Hard to say...  Sounds like it's gotta be built to be properly tested, and the cool thing is that this one's so simple that building it and tweaking it physically would probably be easier than going round and round with circles of speculation until someone finally does some impressive math to get to the bottom of it...
I'm tempted to warm up my soldering iron and dig up a perf scrap now... But gotta go to practice soon... DAMMIT! Why can't I figure out how to be in 2 places at once?

[vanessa]

I'll find the unity gain either way and let you know the resistor value to use. I'm breadboarding this as I'm writing. It's funny but I have the Bazz Fuss already setup on one of my breadboards from over a year ago. 

[vanessa]

You were right Pete (and others), the LPB was totally drowned out by the Bazz Fuss. I also did not really like the LPB at full volume by itself it seems too fuzzy itself to be used as a clean boost. It's been awhile since I've messed with the Bazz Fuss and to tell you the truth I was not happy with the way it clipped (way too hard). I messed with the input/output caps for a while and I really could not find a tone that I liked. I wish there was a really small circuit that I could use as a boost in something like this that would compete with a fuzz section.

[markm]

Mini Booster? 

[vanessa]

I'm thinking Mosfet boost of some sort. Loads of clean db's. Maybe it needs a buffer before the split?

[markm]

I'm thinking Mosfet boost of some sort. Loads of clean db's. Maybe it needs a buffer before the split?

True.
The mini will add it's own flavor it's own right.
I'd like to see something become of this circuit because I think it has potential.
Good Luck, 

[Meanderthal]

 Try Tim Escobedo's CMOS boost- VERY VERY simple, VERY clean, and VERY powerful! I love the way it sounds too. Hard to believe a clean boost can make such a difference! Built it, and WOOHOO it deserved an enclosure!
That's one of the pedals I actually USE!

[Meanderthal]

 Oh yeah, The cmos boost leaves 5 gain stages unused.  Maybe use some of them as a "tube sound" distortion, and get both the clean and distorted sides from a single chip... would be a complete redesign, but could be configured(fixed resistors in place of gain pots) to preserve the concept of a simple flexible distortion/clean blend with a one knob control...  and might be closer to the sound you had in mind!