Crazy oscillating fuzz design ideas

[smccusker]

Hey everyone,

It's been a few years since I've done any DIYing for one reason or another, but I've started to get back in to it recently. I just breadboarded up the axis face from fuzz central and I was thinking of a few modifications i want to make. I want to be able to switch from the straight fuzz to a crazy self oscilating noisy fuzz. Ive been tinkering around with adding feedback to the fuzz face circuit and I'm liking the results so far. I was thinking i would like to add a cheap and dirty "gate" to the end of the circuit to tame the oscillation in between notes etc. My idea so far is purely theoretical, i just thought of it on the bus on the way to work this morning. I just drew up a quick diagram of how i think it could work, but i'd like to get some outside input because it's been a few years and the cobwebs need a bit of dusting.



I figure I'm going to hack the envelope follower from the Nurse Quacky and couple the LED to the back end of an optical style tremolo for the "gate" control. Can anyone see a reason why this wouldnt work? Keep in mind that this pedal is supposed to sound ugly and crazy, so i"m not terribly concerned with fidelity. In fact the cheaper and dirtier, probably, the better. The only thing is i'd like some degree of control for the decay shape and time, so i can get longer decay times or just hard cuts etc. I would use a second 3pdt switch to switch the feedback and gate on. I'm gonna get some bits and pieces and breadboard this up and start tinkering with it. If anyone is interested i will keep this thread updated with my findings. Any ideas or input would be greatly appreciated!
It feels good to be back in to it 

-Sam

[mth5044]

Have you looked at the Uglyface yet?

[smccusker]

cmon, where's the fun in that?

[Ratbones]

Hey, I'm working on something similar, and I'm trying to adapt the envelope follower from the Nurse Quacky schematic too.  I'm having trouble picking it out of the schematic and I wonder if you have had any luck with it? Is it the IC in the schematic that controls the envelope follower? If so, how do you go about pulling just the envelope follower from this circuit and adapt it to another wah for example?

[smccusker]

I haven't gotten any further with this. At a fairly rough guess i would say that the whole bottom part of that schematic from the sensitivity pot to the range pot is the envelop follower. From memory one of the LEDS in this circuit lit up to follow the envelope, which is why i thought it would be suitable for my idea.

[SISKO]

Ok, for FF style circuit (Axis, Si, Easy, etc):

A resistive element between the circuit V+ and the actual power source, make oscillate the circuit. In other words, a 10k pot in series with the battery will make a siren sound. (Look the Fuzz Factory for a glance)

The "gate" control may be a pot in series with the collector of Q2 to missbias it. Or it could be a 500k pot in series with the 100k feedback resistor. (Again, check for the fuzz factory schem and the Wholly Mammoth schem)

[smccusker]

ooo, i am going to try those out right now.

[smccusker]

so i put a pot in series with the battery, and i am getting some cool sounds, although it's not oscillating on its own. I noticed that the Fuzz factory uses germanium transistors, and i am using silicon so maybe the has something to do with it? if i physically add a feedback loop via a 500k pot from the output to the input i get some pretty bent sounds. i think i will add an output for an expression pedal to control the feedback amount, because at certain sweet spots of the gain and starve pots it sounds really cool when you sweep through the feedback pot. Starving the voltage acts as a kind of gate for the feedback at a certain point. I will keep mucking around with it

[SISKO]

Thats funny, Ive tried it in differents FF style circuit and it always worked. Although they were all Ge (pnp and npn), buffered, standard, etc. From motorboating to Matt Bellamy`s kind of noise

One thing to notice is that I made a mistake, the oscillation pot should be in series with the ground of the circuit. Not the V+, but rather in series with the negative lead of the battery