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Horrible hum coming from bypass looper - help!

Discussion in 'Effects [BG]' started by lordradish, Dec 14, 2019.


  1. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
  2. Correlli

    Correlli

    Apr 2, 2004
    NZ
    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.
     
  3. byacey

    byacey

    May 16, 2008
    Alberta, Canada
    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.
     
  4. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
    Correlli likes this.
  5. Correlli

    Correlli

    Apr 2, 2004
    NZ
    This thing looks interesting. Gets really good reviews. Might be worth a try.

    HumX-large.jpg
     
    lordradish likes this.
  6. aj567

    aj567

    Jan 8, 2014
    London
    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!
     
  7. el murdoque

    el murdoque

    Mar 10, 2013
    Germany
    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?
     
  8. Peaveylover

    Peaveylover

    Dec 6, 2019
    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.
     
  9. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
  10. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
    Peaveylover likes this.
  11. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
  12. Peaveylover

    Peaveylover

    Dec 6, 2019
    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.
     
  13. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
    Peaveylover likes this.
  14. Peaveylover

    Peaveylover

    Dec 6, 2019
    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.
     
  15. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    Will do, thanks.
    Could the proximity of the power supply to the bypass looper have anything to do with it?
     
  16. el murdoque

    el murdoque

    Mar 10, 2013
    Germany
    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?
     
  17. lordradish

    lordradish Supporting Member

    Jul 20, 2006
    Vermont
    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.
     
  18. bbh

    bbh Supporting Member

    Sep 27, 2011
    Sometimes it’s a weird pwr issue. If it can run battery pwr, try that in your trouble shooting.
     
  19. 9Thumbs

    9Thumbs

    Jul 3, 2013
    Near Boston
    .....it only hums because it doesn't know the words.
     
  20. nnnnnn

    nnnnnn

    Oct 27, 2018
    Australia
    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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