Input signal amplitude control.

mozz wrote: ↑03 Apr 2024, 21:43 how is it a generalization?

Jake is a dog. Jake is yellow. Are all dogs yellow?
FF is a fuzz. FF has low input impedance. Do all fuzzes have low input Z?

This fuzz could be your his first pedal. This fuzz after a buffer defeats the cleanup sounds different. Fixed it. Not all fuzzes are Fuzz Faces. Please don't perpetuate myths and sweeping generalizations. When the pedal is placed on his pedal board Anywhere on the board?! Is it just the "altit...

the filtration for the different boosts B switch: 220.0 nF 1.5 KΩ 482.3 Hz +3dB H switch: 68.75 nF 470 Ω 4928 Hz +12dB L switch: 1.0 uF 1.5 KΩ 106.1 Hz +3dB L activates both a high-pass (C30, R14) and a low-pass (C29, R13) with the same corner frequency so that should result in a ~3dB bump around 1...

FWIW, there's a "Schematic coming soon" over at PedalPCB and someone (re)traced it: https://forum.pedalpcb.com/threads/missing-build-docs-schematics.3784/page-53#post-213182 I'm not signing up just to look at an overpriced buffer but that schematic is also available in a sim: https://every...

Get a multimeter and use it to see if it's really faulty first.

Then the first step is to get a multimeter and learn how to use it.
Or if you have no interest in electronics and just want it fixed get a tech to look at it.

Do you have a multimeter? Or at least some means of detecting continuity (e.g. a battery, resistor and an LED)? It looks like a stereo jack in the usual battery-saving configuration (but for "negative ground"): http://beavisaudio.com/techpages/pedalpower/#:~:text=Using%20the%20Input%20Jack...

txjeff wrote: ↑30 Dec 2023, 22:30 an item I'm interested in reselling

Are you still planning to sell it after you've replaced all of the components, including the BBD? As an original EHX?

the larger that resistors value becomes will make the input of U1a more sensitive and hence far more prone to picking up any noise I see what you mean now: higher input Z = more susceptible to interference. Keep in mind that no matter how high it is it will get shunted by the source's output Z. So ...

phatt wrote: ↑19 Jan 2024, 05:34 issues that I've missed.

You've missed the fact that the biasing resistor has nothing to do with setting the gain of a noninverting op amp, and that impedance in parallel with the input doesn't add to Johnson noise, so your entire premise is false.

Is this pedal almost 20 years old?
How about everything else he builds? Using perf for serialized manufacturing is just shooting yourself in the foot.

The man sure loves his cheap perfboard.
Does he know you can order proper PCBs for pennies per unit?

Keep in mind that Bluetooth adds latency. Otherwise you can easily build one with an ESP32 and I2S ADC: https://github.com/pschatzmann/ESP32-A2DP

Do you mean "follows your fretboard/input signal" like a harmonizer does? Try a couple of octaves up or more (+additional distortion).
Aliasing also kind of does that but in "reverse".

Excuse me sir but WTF is a "passive buffer"?! What you're describing would be an un-buffer (and probably accurate).

OK so
1. Schematic pretty please? How else are we supposed to know what things like "Q2" are supposed to be doing?
2. Did you check the biasing?

1. Schematic
2. Op amp biasing is no good but I don't think you got the pin order right so it's harder to tell what's going on. Pins on an IC are counted counter-clockwise:

MINUS 7V, so one can use the PNP setup without all the "positive ground" caveats.

The simplest explanation is they fucked up when adapting it to single supply.