The BMF Fuzz, will this work?

[vanessa]

Just a variation on the Bazz Fuss. I'm calling it the Bazz Mix Fuss Fuzz or BMF Fuzz for short, LoL. It allows you to mix the fuzz with a clean signal. I've found the original to clean up well but hey there's always room for improvement right? 

[Meanderthal]

I Like it! Simple and efficient, yet flexible! Nice clean drawing too!

The only 2 issues that would worry me would be:
The mpsa13 is a very high gain darlington I think. Might be a good idea to add a gain pot at the front of the bazz fuss, or maybe an attenuating resistor after it so it dosen't overpower the FET stage, or maybe just use a log pot for the blend to compensate somewhat...
The only other thing is partly my ignorance/apprehension about biasing FET's. If it farts I'd put a trimpot between the 9v and... that upper leg there(I told you I'm stupid when it comes to FET's). I couldn't possibly have gotten my thunderchief build to work right without those trimpots.

Other than that it looks great to me! But I'm no expert....

[markm]

The 10K pot mixes the Fuzz and clean?

[Lateksi]

I think I see a problem there.
The distortion stage is inverting, while the clean buffer isn't. Mixing them would decrease the amount of frequencies the were originally in the signal, leaving only ones generated by distortion. While it may sound "interesting", it's probably not the sound you were after.

[vanessa]

I think I see a problem there.
The distortion stage is inverting, while the clean buffer isn't. Mixing them would decrease the amount of frequencies the were originally in the signal, leaving only ones generated by distortion. While it may sound "interesting", it's probably not the sound you were after.

How would I remedy the issue?

[MartyMart]

How would I remedy the issue?

Take the output of the Jfet stage from the Drain and not the source.
You must still use the 10uf cap of course
MM.

[vanessa]

Something like this?

[vanessa]

The 10K pot mixes the Fuzz and clean?

Yes. Sort of like VDL Sparkle Drive (more like Robert's Sprinkle Drive) or use of a mixer (Bass Paralooper) but with a Bazz Fuss. My idea is the circuit would be so small that you could fit into the cavity of a guitar with ease. The PCB would have the option to use a trimpot for the mix control.

Do you think 10k is a good value? Maybe 50k?

[vanessa]

50K?

[Mark Hammer]

I don't know disrete circuits well enough to do the appropriate calculations, but...while it looks to me like the circuit would "work" just not very well.  I have my doubts about whether the gain of the FET side would be anywhere near enough to compete with the output of the darlington side.  So, you'd be able to blend but the bazzz side would always drown out the clean side.  Or so it would appear.  Am I way off on that?

[vanessa]

I did think of that. I'm wondering if using the right sized pot and maybe a log pot like Meanderthal said might compensate? I could also add a simple boost (LPB-1) before the FET stage, would that work?

[vanessa]

Although it would increase the part count, do you guys think that this would work with the AMZ Mosfet boost instead of the JFET buffer?

What would be cool about that is the unit could be used as a boost, a fuzz or dial in a combo of both.

[slacker]

I'd try something like the last transistor stage of a Big Muff in place of the JFET that will give a good clean boost.

[Dragonfly]

...ive done a very similar fuzz, but to help with the volume issues i simply put a master on the fuzz and a master on the boost....iirc, a 100k on the fuzz and a 500k on the boost...i personally liked the sound of a LPB style boost better than a fet boost when mixed with the fuzz...

best of luck,
   AC

[vanessa]

Dragonfly, what about your SSMB boost? How would that sound and do you have a schematic for that?

[billings]

Taking the signal at the drain like that in a source follower configuration like that pegs the output at +9V.  A unity gain common source amplifier would invert the signal and buffer the output.

I like the idea of sticking the MOSFET booster in there as a buffer, taking the output from the drain.  A unity gain LPB-type amplifier stage would also be good for a lower impedance output than the MOSFET booster, although I wonder if that might load down the input signal and make the fuzz signal path a bit more tame?  That might not be a bad thing, I guess.

Is it possible that cancelling the fundamental could be musically useful?  Probably not for a bass fuzz, but if you use the MOSFET booster there is that extra non-inverted output on the source to play with...

[vanessa]

What about something like this? Would I run into any issues?

[petemoore]

  Perhaps just voltage divide the darlington output so as to reduce it's output to closer to what the Jfet is putting out.
  Stick a 500k wired like a volume pot from the Darlingtons output cap, other side to ground, wiper to the 10k [cut the connection between C3 and the 10kpot, insert adjustable volume divider there]...adjust to desired level, remove and measure both sides of the pot and replace with fixed resistors.
  And socketting C1 and C2...for different voicing on the clean [maybe let the bass in here..or] and Dirt [voiced for nice high end grit..or], since they're there and could be interactive with the balance control, it might be worthwhile to sample values.
  C3 and C4 are also voicing caps...lol...might be time to warm up a breadboard.

[vanessa]

Are you speaking of the JFET buffer version or this LPB version?

[Meanderthal]

If you were to move the pot r5 up to the tail end of the bazz fuss stage you'll have that attenuator I was talking about.                                      It needs it more than the boost stage. A darlington is a much more powerful transistor type than either bjt or fet types. A darlington's output is the equivalent to the output of a bjt TIMES itself(squared)! That's a lot of gain! I wouldn't change that darlington to another type to compensate however- by all accounts it's perfect for the bazz fuss. I know it certainly sounds good on the whisker biscuit!