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There are some application notes for the ca3080 here
https://www.experimentalistsanonymous.com/diy/Datasheets/AN6668.pdf

A ross-style compressor is an application like you want (single power supply and amplifier). E.g. https://www.madbeanpedals.com/projects/_folders/Compressor/pdf/Kompromat.pdf.

Spaceman Effects Aphelion is also a very interesting ota-based pedal (diy board and schematic here https://www.deadendfx.com/product/anticarus)

Nice job as always, that discrete OTA has me jealous!

Nice build! And very nice demo! Some great sounds there!

Whats up with the bias arrangement for the op amp stages? I'm not very used to the 386, does pin 7 provide a Vref?

This one is nothing revolutionary but sounds amazing and was fun to develop: idea -> LTspice -> breadboard -> eagle -> final build
I've always liked the way jfet boosters and overdrives sound with solid state amps (the kind of amp I play the most) and so I've decided to try some MuAmp with a Range potentiometer of sorts that mixes a 2u2 bypass cap in parallel with a 100n.

I've used two 2sk117-Gr transistors, that give just a tiny bit of dirt with single coils. It distorts a bit more with humbuckers, but is cleaner than a typical rangemaster.

Perfect, thanks!

Hey guys, how are you doing?

I'm itching to order some v3208 chips and build me some analog delay, however, the v3102 is nowhere to be found.
What I do have is a little stash of mn3102.

My question is: can a combo MN3102 V3208 work?

Thanks!

Thanks for the insights, everyone

Can you  sysyematically isolate the problem? I had a bad guitar lead cause that once.  Id start by swappping out leads with known good ones

I'm thinking it might be guitar related (my cheap Epiphone is the worst), but, as I mentioned, gain pedals are where I typically listen to it

If you are using shielded wiring, make sure to only ground the shield on one end. Also, avoid ground loops.

Yeah, I definitely need to learn better grounding practices (I'm thankful if you guys have any suggestions of reading materials)

I live near a large tower, but I always thought my RFI problem was specifically tied to pedals. Turns out that within my guitar, the input wire was routed to the jack such that it was basically laying across the cable tip when inserted. As soon as I fixed that it got a lot better. I still get some RFI with fuzz/octave type-pedals, but even that is reduced from before.

Will have to open my guitar and check it, might be the case

Is it mainly gain boosting pedals you are having issues with? Does powering via battery help?

Most of the time it is the gainy pedals, indeed. Batteries usually do not help much (of course they help with a little of hum, but not with RFI)

Thanks for the replies!

In addition to your usual noise filter capacitor (large value electrolytic), try adding a very small value MLCC in parallel from DC + to ground.  Try some value between 4.7 pF and 22 pF.  The large electrolytic caps don't help much with radio frequency noise.

I've never used such small values of MLCC in parallel with the electros (only the more usual 100nF), will give it a try

Is a transmitting tower near your house?

Not that I know of, but I do have a lot more trouble with RFI at home than at practice

Is your enclosure metal and grounded?

It is, and it certainly helped, but did not solve the issue

Hey folks! How are you all doing?
I've recently had some bad luck with pedals and RFI.
I've usually been able to deal with it (with varying degrees of success) using low pass filters (RC) in the power supply and at the input of the circuit. It works ok, most of the time, but seems to be a bit random.
Is there anything else I could be doing to improve it?

Is that just a couple of parallel si diodes with a trim pot?

I don't know exactly what the diodes are doing, but this is a rather common implementation of a simple noise gate in distortion pedals. It does add crossover distortion, though (I believe the parallel trimpot is there to balance the amount of gate and distortion)

Edit: just found a nice explanation of the circuit: https://www.reddit.com/r/diypedals/comments/2tljn4/a_fancier_noise_gate_for_highgain_pedals/

Nice job! It looks awesome!

Some three years ago, I posted a question about making a darlington pair out of two BJTs for the Bellows. Breadboarded it and it worked nice, but I've decided to wait and buy a proper MPSA13.
Fastforward to last weekend, I have finally remembered to order the MPSA13, but all of a sudden, I can't wait 3 days for the order to arrive and build the pedal using a pair of matched 2n3904 (hfe=190, if my multimeter can be trusted), and I'm happy I did, cause it sounds awesome.

Simple graphics and messy guts for you to enjoy:

Such a nice story and a very good looking build!

Which amp is it? Maybe there is something online that we can check to verify what's going on. I would guess the aux input is somewhere still in the preamp, so that if the preamp is bad, aux is partially affected.

Thanks for the answer, thomasha

I found the schematic and the block diagram. The aux input is right after the tone control, so I'm guessing it shouldn't be affected by the preamp (and the preamp works fine, problem is with the jack).

Use those DIY skills to have a look at the jack.

It's probably my best guess, but I'm too lazy to open the amp