Favorite Bazz Fuss Mods, Anyone?

[thehallofshields]

You can try a big bypassed emitter resistor to send the collector above 7-8 volts... just guessing.
A pot wired as a variable emitter resistor with a 47uf cap can do it.

mac

I'll try that when I get home.

[thehallofshields]

You can try a big bypassed emitter resistor to send the collector above 7-8 volts... just guessing.
A pot wired as a variable emitter resistor with a 47uf cap can do it.

mac

I'll try that when I get home.

I tried it. No luck.

At 100k it starts getting a little muffled and boomy.
At 500k it starts to gate and cut-out.

Not much a change in texture unfortunately.

[mac]

Another diode in the other way rounds things even more...

mac

[raven72]

Does the potentiometer have a capacitance value that is affecting the sound that a pair of resistors don't?

The capacitance of a pot, if any, is much, much less than the bypass resistor.
Is your potentiometer linear or log?

A darlington Bazz Fuss has the sustain of a muff, but sounds like it's all even-order instead of odd-order harmonics. Is there any way to rebias it to change that balance?

You can try a big bypassed emitter resistor to send the collector above 7-8 volts... just guessing.
A pot wired as a variable emitter resistor with a 47uf cap can do it.

mac

Solved the problem....going with a mini PCB mounted pot....oh, and its a 50k linear

[thehallofshields]

Another diode in the other way rounds things even more...

mac

mac, does your mossfuzz get symmetrical clipping?

[mac]

mac, does your mossfuzz get symmetrical clipping?

With two diodes back to back, the spice plot looks so.

BTW, I noted in the schematic "any mosfet will work", but I have to add that some will sound better than others.

mac

[whoisalhedges]

Saw a schematic for a Ge Companion yesterday afternoon. Loving the FY-2 as I do, I had to give it a try. I have an AC127 and a beautiful black glass OC140, Hfes around 60-70, low leakage - reoriented the schematic for NPN, and went to work.

Try as I might, I just couldn't get it biased right. Too much + was getting in at my collectors! Tried a half dozen different Rc values, to no avail. Anyway, I didn't want to waste my breadboard time, so I used 'em to build a Ge Darlington Bazz Fuss. I'm glad I did.

Figured it could use a little smoothing out, still got a little farty at the highest amplitudes; so in went a couple Ge diodes back-to-back at the end - oh yeah, that's my other mod, I put the pot at output as a volume control rather than at the beginning. But everybody does that, right? (sorry, Hemmo)

Sounds absolutely killer. It's got a background synthy vibe; but a little more dynamic than the Si Bazz Fusses I've built. It's a neat little circuit.

[Clips]

I dont know if this has already been mentioned (I skimmed the topic and didnt see it), but I really like to make my own darlingtons when designing Bazz Fusses. You just take two regular non-darlington npn's, and wire them like so: https://upload.wikimedia.org/wikipedia/commons/thumb/7/78/Darlington_pair_diagram.svg/2000px-Darlington_pair_diagram.svg.png

This lets you mix and match different types of tranistors to get a mix of flavors -- I currently mix a 2N3904 with a low-gain audio bjt I pulled from some scrapped mixer and am happy with the strange dialed-down tone it gives me. Need to finish that project up actually, just gotta fine-tune the filtering and put that baby to work.

I also gotta suggest using a schottky diode or a germanium and see if you like that crazy-hard clipping. Even more synthey madness!

[mac]

This lets you mix and match different types of tranistors to get a mix of flavors -- I currently mix a 2N3904 with a low-gain audio bjt I pulled from some scrapped mixer and am happy with the strange dialed-down tone it gives me. Need to finish that project up actually, just gotta fine-tune the filtering and put that baby to work.

Good point.
A high internal capacitance device like BD237 after a 2n3904 filters a lot of highs.

BTW, I never tried a Si-Ge darlington, maybe because temperature issues...

mac

[mayoayox]

Working on a 1 knob Bazz Fuss to box up and forget about, cause I love the circuit and I have a 1 knob pre-drilled enclosure.

I like the sound of a BF with the pre-gain rolled back to get a small speaker sound.

sadly the BF is too loud, but I fixed that by measuring resistances with a volume pot. and then approximating those resistances with what I had on hand. so the resistor network at the end is a kind of attenuator.

I also added a diode at the end.


I'll be doing this again tomorrow, except back to basics with a MPSA13 and trying out a bias control with a volume control. So the next BF I do will be a two knob.