Hi
I built a pedal for myself, it worked great, then I decide to sell it.
It was based on the MI audio crunch box / Guitar PCB crunch which of themselves are Op Amp based diode clipped "Marshall in a box" effects
Guy has written to me saying he cant use it anymore as it simply produces a high pitch sqealing sound at any volume; nothing else has changed in his setup or powering etc.
Any thoughts for things for him to check before he posts it back?
thanks
Ian
Aks him whether or not he had used a laptop power supply. I've had a case just like that and the guy was actually nuts...haha.
On a more serious note, I've had a couple of cases occur where cat hair had been the culprit. This is also the reason why I meticulously rock before I box. I love my cat, but pedal-wise, it is nothing but problems :D
I suspect you are not getting the whole story. Sounds like a wrong power supply issue to me :-\
If it isn't a bad PS, or damage from an incorrect PS, then it's either a problem with the wiring or a component failure. I assume you work is good, so perhaps it is a component failure - likely a cap or IC.
Request some gut shots to verify wiring - and that he hasn't tried to screw with the pedal.
I'd send him 2 new IC's and see if he can fix it himself.
Does the volume and presence knob work?
A good gut-shot might help to show any obvious issues (disconnected wires, shorts etc.).
Also get him to take a photo of the PSU he is using and have a look.
From my experience some people will just stick whatever PSU they have knocking around into a pedal and expect it to work.
It could also be how he set up his signal chain. Recently I tried a configuration where used a splitter to send my input signal to two different pedals and combined the signal back at the amp. It worked fine if you just used one pedal at a time, but when you turned both on at once, it squealed like crazy.
Gremlins.
waiting for feedbck from the fellow
he isnt the kind of person to go taking stuff apart, and he had everything on a pedal board set up, so I doubt he ran it independantly with some crazy PSU.... but it can happen I guess.
Worst case is I have to replace some parts or rewire something.
So if you think it's an honest fellow then don't waste any time. Fixing this pedal sells your next pedal.
its not a problem with just this pedal now, apparentyly
he has tried with a boss psu, as well as his DC brick (8 x 9v supply) as well as testing his other overdrive and fuzz pedals, and they are all causing a squealing sound through his amp.
ill help him figure out what it is! but its clearly not just my pedal that is faulty.
Quote from: LaceSensor on October 01, 2014, 10:28:42 AM
Hi
I built a pedal for myself, it worked great, then I decide to sell it.
It was based on the MI audio crunch box / Guitar PCB crunch which of themselves are Op Amp based diode clipped "Marshall in a box" effects
Guy has written to me saying he cant use it anymore as it simply produces a high pitch sqealing sound at any volume; nothing else has changed in his setup or powering etc.
Any thoughts for things for him to check before he posts it back?
thanks
Ian
9 times out of 10 it's the PSU they're using. Had it happen a few times with people plugging my stuff into shat PSUs.
Saying that, I have made stuff that's seemingly gone bonkers. They were the first multi's I let into the wild and they had multiple clocks in them... Doesn't always manifest in testing.
Also had a bad trimmer cause fun and games...
Damaged PSU socket too...
...and the old favourite of them sticking an AC or 18v PSU into a 9vDC pedal....
apparently it does it with any psu he has
further chat says that
1 - the amp will sqeal like this on the gain channel (marshall TSL)
2 - doesnt squeal on the clean channel, or with other pedals (delay, phaser, compressor) using same PSUs etc
3 - will squeal with any gain pedal added, clean channel included
therefore, I am recommending he checks for microphonic tubes as the first port of call...
thanks for all info
Could also be a microphonic cable. Have him plug directly into the amp and see if it still happens if it does then check the tubes.
Richard
...or the pedal could be female...
Quote from: juansolo on October 01, 2014, 06:17:58 PM
...or the pedal could be female...
Oui, bien sûr, vraiment, c'est
la pédale!