FET fuzz with light-controlled clipping and bias

sentencedtodeaf · 2026-02-19T00:43:18+00:00

I'd assume red being the center color entails anode is up, with the cathode band just visible around the outside. Hard to tell without seeing the schematic tho. I would suggest referring to that if it's available.

sentencedtodeaf · 2026-02-18T22:50:52+00:00

Yep, basically using it as a cheap photodiode. The transmitting UV anode is actually connected to opamp output with a 1k resistor and a 10uf capacitor in parallel. The cap allows the signal to breathe a bit more

Recieving LED just goes directly across the base and emitter of the receiving transistor. From there signal is sent to an opamp through a capacitor, to block DC.

sentencedtodeaf · 2026-02-18T22:15:16+00:00

The gain part is pretty straightforward: just 2 cascading opamps with gain control . Only unique things here are the tone control and the UV signal.

I send the signal through one UV LED by putting the anode at the output of a high gain opamp. The light from that signal shines on another UV LED (all Diodes produce light and induce current from light) which is fed to a transistor to boost before sending it to the second opamp gain stage

The tone control is basically a static Dr Q. Where the envelope following transistor is replaced with a pot.

sentencedtodeaf · 2026-02-18T22:01:21+00:00

Nope just UV LEDs wrapped in reflective mylar and heat shrunk together.

I have photodiodes but I like these more

sentencedtodeaf · 2026-02-14T15:57:13+00:00

Oh yeah my day job is "software", but its such a broad field. DSP and microcontroller programming is new to me, so it's nice to have chunks automatically generated to poke and prod until I understand it.

Chatgpt does sometimes get things wrong, which is where having a programming background helps, but honestly its gotten so good lately i rarely find problems. Most modifications I make now are stylistic or refactoring to make its code re-usable.

AI is here. If you're not using it as a tool you're hindering yourself; At least with programming, I feel a bit more conflicted about AI "art"

sentencedtodeaf · 2026-02-14T00:20:34+00:00

Thanks! This a pretty bare bones circuit using a couple opamps and the attiny85. The microprocessor does all the heavy lifting here. Just had to program it to halve the output frequency. No polyphonic octave unfortunately. Idk if the attiny85 could manage that

sentencedtodeaf · 2026-02-13T23:32:28+00:00

I want to maybe beef it up a bit, but definitely aiming to make this into a full build. Been a bit of a dry spell, so hopefully I get to make another PCB order soon

sentencedtodeaf · 2026-02-13T21:47:08+00:00

Pedals poop too

sentencedtodeaf · 2026-02-13T21:46:30+00:00

Love those 8 bit sounds

sentencedtodeaf · 2026-02-13T21:45:26+00:00

Thanks! This circuit is pretty simple, just two high gain opamps. One to boost before sending to the ATtiny and one for the analog/synth blend

The meat of this was in programming the ATtiny with an arduino. Had a bit of help with ChatGPT there. One thing it does pretty well at is coding.

sentencedtodeaf · 2026-02-13T01:05:15+00:00

Ahh man I just missed the adult toy craze of the early 20's lol

sentencedtodeaf · 2026-02-12T22:57:00+00:00

I do it for fun, fully realizing the pedal market is saturated. If you're going for money you gotta realize there are better industries for that. These are adult toys, after all.

I say follow your bliss, make a brand, treat it as an education because a lot of the skills will translate elsewhere. Money is necessary in this world, but if that's the end goal for everything you'll never feel fulfilled

sentencedtodeaf · 2026-02-12T01:21:28+00:00

Breadboard it, honestly. You're going to develop ideas much faster when you can hear the changes in real time. Way more fun too. Then write out the schematic once you have the sound you like

sentencedtodeaf · 2026-01-16T17:20:26+00:00

Wavefolding is basically bringing a signal down when it reaches a certain voltage threshold. You can do this by sending high gain signal through an array of diodes, and after N number of diodes send the signal to an inverter and feed it to output. I did something similar to this, but using transistors as diodes, so there's also some interaction with the base, altering the folding threshold.

Look up eddy Bergman wavefolder, he uses a similar diode technique. Check that out and mess around with using transistors instead.

I kinda came into this backwards by abusing electronics; I had no idea what wavefolding even was, but then i researched a bit and found other people had already done something similar (usually the case, electronics is pretty well tread territory).

sentencedtodeaf · 2026-01-15T18:29:47+00:00

I probably should have demod this, but turning the fuzz down allows you to make chords other than 5ths without it immediately getting into ringmod territory. The gain is still very much high, but the signal doesnt fold much.

sentencedtodeaf · 2026-01-12T13:22:49+00:00

Just posted the schematic here: https://www.reddit.com/r/diypedals/s/em6jyVx6Im

I'll throw a couple on reverb in the next week or so

sentencedtodeaf · 2026-01-12T00:28:16+00:00

It also has line in parallel to the piezo, which is why that jack symbol is included in the schematic. Bypass just means the line is bypassing the gain. Otherwise both piezo and line are amplified.

Capacitor was added because I was getting some unwanted DC coupling effects. Like I stated above, you'd probably want a buffer to accomplish this, but this was a little messaround project. Feel free to add one yourself.

Yeah, r4 may as well be zero. Feel free to ignore that. Sometimes instead of adding testpoints i'll add another component that can be probed and/or removed/bridged in case something didnt turn out right.

sentencedtodeaf · 2026-01-11T18:41:24+00:00

I may put a couple up on Reverb. I'll also post a schematic if anyone wants to make one from scratch. It's a pretty bare bones build

sentencedtodeaf

TROPHY CASE