Well, after lots of time and money, I finally have my big pedalboard set up for stereo. Yay! Sounds amazing, except for one thing. I have an American Loopers bypass looper, a pretty big one, has 6 mono loops and 4 stereo. Now, for a reason I can't figure out, whatever pedal is on loop 10 (the last loop), there's a constant and obnoxious hum. I sent it back to American Loopers, he couldn't reproduce the problem, even sent me a video showing how he couldn't reproduce it. He tried it in stereo, as well as mono, as well as each side. I've tried to troubleshoot, here's what I've done, all of which made no difference. Put other pedals in that slot Doesn't seem to matter if other loops are engaged, or not Tried it just mono Tried another new cable Put the pedal on it in another slot (didn't make noise on that slot, so it's obv. not the pedal). Powered it from one iso power supply. Powered it from another iso power supply Powered it with its own power, just plugged in The looper goes back to an Empress stereo buffer, to a DI, then XLR's out to my PA. Tried the ground lift on the DI. I'm kind of at my wit's end, here. The looper is so quiet, except for that last loop, and I need that last loop, too. What could this possibly be? Out of options, here. Also gonna post this in the repairs section, hope that's okay.
I got some noise through my pedalboard in my practice room. Turned out to be coming from the power outlet. My next step is a Furman power conditioner.
Save your money. Those Furman units are a glorified power bar, and their idea of power conditioning is some varistors between the hot, neutral and ground to clamp any transient spikes to ground. They do nothing else with regards to power line noise.
The only thing I haven't tried is plugging it in to an outlet that I know it is on a different circuit. Just spent another hour trying different things. Baffled.
Test ALL of your patch cables and pedals individually. This reminds me of an extremely weird issue I had, where one pedal would introduce a noise when engaged. Did basically everything you mentioned, sent the pedal for repair, fault couldn't be reproduced. Turned out to be a dodgy patch cable on a completely different part of the board. Totally counter intuitive, but the problem that appears to be in loop 10 might actually be some weird grounding issue in loop 2. Good luck!
What happens if you bypass the bypass by connecting a cable from the output 10 to input 10 ? And what frequency hum are we talking about?
Could be a pedal with a charge pump making the noise. Bit I also think American Loopers are one of the worst companies out there. I got one completely broken from them and they tried to blame me. They even "took a video of it" to prove the fault was mine. The only way for me to get my money back was to write them a terrible review and tell them I'd remove it if they did right by me. I never even considered them after that was resolved.
Actually, after I posted, I went and unplugged everything except loop 10, still had the noise. Thing is, the cables are pretty new, but I'm gonna try some other ones, tonight. Thanks.
You know, I didn't want to go there, but there is something in the back of my mind that has me wondering about that side of the equation. What is a 'charge pump'? I've tried it with different pedals in that slot.
I don't know what frequency, but it's that typical hum you get when you have a bad cable or something. I haven't tried bypassing the bypass, but I will try that tonight. Thanks.
A charge pump is when a pedal increases the internal voltage, say from 9 volts to 18. Or from 18 to 36. These pedals always introduce a whine or whistle into a bypass looper and there is no way I've found to remove it other than turning off the pedal in that loop. And you gut feeling on "that side of the equation" may be right. American Loopers is not a company I'd ever do business with again after my experience with their programmable looper.
Thanks for the explanation. The pedals are Meris pedals, perhaps, just for the heck of it, I should try a different one, like my H9 in that slot. I've been looking around on the internet, I don't really have a lot of other options, as far as this many stereo loops, the RJM is the only one, and I can't drop over 800 on a bypass looper, now. If I can't fix this, I'll just have to double up two pedals on loop 9. I did buy this used.
Sounding like one of those has a charge pump in it. Best way to diagnose is to remove pedals one by one and see if the noise stops. If it does, google the pedal in question to see if it does have a pump. If it does, problem solved, although using that pedal might be a problem.
Will do, thanks. Could the proximity of the power supply to the bypass looper have anything to do with it?
Another hunch: could you, while testing, unplug the looper's power source? I guess it's a simple, passive unit with only the LED's needing power?
I don't know if it's purely passive, it does have preset and midi capability, which I don't use. The thing does have a big circuit board in it. But I'll try that, too.
Always? No they don't. I have two pedals with charge pumps in separate loops of my bypass looper, with no problems no matter what combination of loops I use.
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