HAARP: intermittent static & noise

Stickman393

Well-known member
Just put together this build. Everything works as it should, but I'm experiencing something strange with it...

Play a note, boom. Lovely arpeggios and wild stuff...but also intermittent static. It'll die out as the note sustains, but it sounds like crinkling a plastic bag in like 3-4 pulses in time with the arpeggios after I pluck. It's certainly more pronounced playing in lower registers. It's only occuring in the wet signal.

First off...I've gone over my solder joints, re-flowed everything, swapped the op amps, tried with a few different power supplies. No dice so far. The FV-1 was sourced from antique electronic supply.

Any ideas where to start here, or anybody experience anything similar with an FV-1 project? The 3.3v regulator, the crystal? Just start probing away?
 
Whelllllllp....

Found something here.

I noticed my 1 pole 8 throw mini rotary switch was operating...eh...strangely. Pulled it, position 1 no connection, position 2 common to pins 1 and 3, position 3 common to pins 2 and 4, position 4 common to pins 3 and 5, ect through position 8.

Could be a bunk switch. Can't say I've ever seen something like this before. Confirmed with a brand new one from my stockpile, Common to 1, common to 2, common to 3...

Don't have time tonight to give it a full test. We'll see tomorrow...
 
I would expect Antique Electronic Supply to be a solid FV-1 source, so that rules out a bad FV-1. The fact that you're getting signal processing means your crystal is likely fine, and in my experience 78** regulators typically fail open, meaning if they go bad they'll pass 9V to the output, so if your regulator was bad you would have already fried the FV-1, which doesn't seem to be the case. I've had similar noise issues to what you're describing with one FV-1 build because one of my op-amps was bad, so that's one other thing to look at. I've never personally heard of a bad switch causing problems like that, but if you know your switch is bad and you have a replacement, by all means see if that fixes it. You could also jump a wire from the common pins to one position at a time to see if that works, and that would clearly point to the switch being the culprit.
 
Switch replaced, but unfortunately that only solved the problem I didn't realize I had.

This static-y noise was keeping me from focusing on the fact that the arpeggios didn't seem to be changing much. Now, they switch just fine, but that static is still present.

I noticed an issue with C5, the problem kinda morphed into constant static background noise that went away when I pushed down on the cap. It still had that crinkly plastic bag effect on the first few repeats there though...swapped that one out. No dice.

Swapped op amps, regulator, C5,
Poked around and checked all my values. No dice.

Whellllp. I should probably see about checking voltages and yada blah.

Could be I just got a bad FV-1 in the batch. I've got a handful of them for builds I have planned...but de-soldering one of those? Woof. I mean, pedal PCB boards are great in a lot of ways but I've got shit luck with de-soldering components on them. This board's already got like three jumpers on it.

I'm still going to go through the troubleshooting motions on this one...but knowing myself I'll probably end up buying another board and give it a fresh go.
 
Fuuuuuuuuu....

Yeah, that ain't right.,

Poking around at everything that should be @ 3.3v...6, 8, 23 on the FV-1 all around 6v, pin 8 of eeprom @ 7v.

Huh. Not a solder bridge in sight.

Okies, I think I've learned my lesson about boxing them before I test em. Time to rip it out and do some point to point testing.

Probably gonna bang my head on the desk for a little while while I figure it out...

*Edit* well, shit. My eeprom probably isn't too happy with me right now. I'm just a hair above the MAV. COOOOOOOOL. Ko ko ko ko coooool.

Ditto on the FV-1. Except it's more like double. sheittte.
 
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