ADHD Feedback Loop

ultradoom

New member
Hello! First post here!

I recently purchased an ADHD off a builder on Reverb and while everything works correctly (though it sounds nothing like an OCD v2) when the buffer switch is set down (can't tell if engaged or disengaged) the pedal generates a super loud feedback loop, with a tone sitting nicely about 200hz. The pedal only produces this sound when *not* engaged. It also changes pitch when plugging in/unplugging cables. When the buffer switch is set to the up position OR the pedal is turned on, the noise/feedback stops. Power cycling the pedal does nothing and no input is needed to generate the loop noise, only a second or two of time for it to ramp up. Buffer switch is the 6 posts soldered on the top left in all pics.

I took a peek and didn't notice anything particularly wrong or obviously loose. Pics included.
 

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Touch the electrolytic capacitors while it's making its sound--I had a similar issue and touching the caps was able to determine a faulty one.
 
It's a long shot, but yes, I would try pressing the 7 wires at the bottom down slightly so they aren't arcing directly above the upper PCB.
 
Alright did some fiddling - was not able to determine any faulty caps while feedback was being produced.

Wires 123 out of the bottom of the PCB to the switch are all microphonic to the point I can hear my finger touching/moving over the cable. Same with the input (top most post left jack as pictured). I also found more or less the whole enclosure to be microphonic and if I tapped the back plate against the enclosure the 'clink' would pass through. Its also interesting that I can get the loop out of both the input and output jack - and that the loop goes away when I use a TRS output cable, though I loose some signal too.

When its connected second-last to the pedal with a TRS out the feedback also stops, third last and its back all the way through to position 1 in the chain, but the pitch will sometimes change). Weird. Plugging directly into my interface I could not get feedback, as soon as I put it anywhere but second last in the chain its back. This was all using an independent power supply to the wall and the PSU supply doesn't seem to matter.
 
Fellas this is one of my builds I sold on Reverb..... I'll have the pedal back soon and test on my rig to see if I can get it to do the same thing... I ran it on my pedalboard for 2 live gigs and had no issues.. just like I do with all my builds.. They go on my board before I ever let them into the wild.
 
Fellas this is one of my builds I sold on Reverb..... I'll have the pedal back soon and test on my rig to see if I can get it to do the same thing... I ran it on my pedalboard for 2 live gigs and had no issues.. just like I do with all my builds.. They go on my board before I ever let them into the wild.
I know how this feels, I sent out a pedal last week and the guy got it and he said the power pulsed on and off on it and I test everything before I ship it so I'm just waiting to hear back if his new power supply solves the issue or if I'm due for some repair work.
 
I know how this feels, I sent out a pedal last week and the guy got it and he said the power pulsed on and off on it and I test everything before I ship it so I'm just waiting to hear back if his new power supply solves the issue or if I'm due for some repair work.
This is why I don’t sell pedals on reverb and eBay. Hell, I sold some Gibson pickups on eBay to a guy that didn’t know the difference between tapping and splitting. He said they were defective, why would I sell perfectly good pickups. That was a huge hassle.
 
This is why I don’t sell pedals on reverb and eBay. Hell, I sold some Gibson pickups on eBay to a guy that didn’t know the difference between tapping and splitting. He said they were defective, why would I sell perfectly good pickups. That was a huge hassle.
Selling pedals is my gig right now so it's a necessary evil, I would prefer to do more off reverb sales, but I'm having trouble getting website traffic and it offers another way to get my products out there in front of more people. I've had another guy get a "non working pedal" and after reverb refunded him (through the safe shipping thankfully) he messaged me again asking for a shipping cost refund from me, but reverb already refunded 100% of the money he paid so I have no idea what was going on with that, I just told him a few times to take that up with reverb and he left me alone eventually. Reverb overall has been pretty good, their support has always taken care of me in a way I felt was fair.

Regarding ebay, my brother just sold a phone on there, it got shipped to a reshipping center and then shipped off from there to a portuguese speaking country where it was claimed to not be working, the guy provided a return tracking number to a completely different state that was delivered before the return/dispute was started and ebay sided with them and charged my brother an additional $20 dispute fee, so he's out the phone PLUS fees so I'll no longer be selling anything through ebay after that experience.
 
Selling pedals is my gig right now so it's a necessary evil, I would prefer to do more off reverb sales, but I'm having trouble getting website traffic and it offers another way to get my products out there in front of more people. I've had another guy get a "non working pedal" and after reverb refunded him (through the safe shipping thankfully) he messaged me again asking for a shipping cost refund from me, but reverb already refunded 100% of the money he paid so I have no idea what was going on with that, I just told him a few times to take that up with reverb and he left me alone eventually. Reverb overall has been pretty good, their support has always taken care of me in a way I felt was fair.

Regarding ebay, my brother just sold a phone on there, it got shipped to a reshipping center and then shipped off from there to a portuguese speaking country where it was claimed to not be working, the guy provided a return tracking number to a completely different state that was delivered before the return/dispute was started and ebay sided with them and charged my brother an additional $20 dispute fee, so he's out the phone PLUS fees so I'll no longer be selling anything through ebay after that experience.
Ah, gotcha.
 
Got the pedal in and confirmed... something has gone crazy.... The pedal is indeed very microphonic.... even tapping on the enclosure you can hear it... touching wire from switch to board is really bad too... gain and volume maxed it will start squealing with a crazy tone like a tone generator...
 
Got the pedal in and confirmed... something has gone crazy.... The pedal is indeed very microphonic.... even tapping on the enclosure you can hear it... touching wire from switch to board is really bad too... gain and volume maxed it will start squealing with a crazy tone like a tone generator...
Advertise it as an experimental microphone and noisesynth. I’ll take two please 😜
 
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