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Grounding issue via DI

Discussion in 'Effects [BG]' started by Microbass, Nov 25, 2018.


  1. My board grown a lot over the last year. I've been using one of these - a Caline power supply. It's a cheap Chinese made which offers all the goods but who knows how well it does these things?
    The power adaptor I'm using into the mains is an off the shelf 18V supply.

    Through my rig there's a barely audible hum with my valve amp, barely noticeable with my class D. Through the DI into a PA however on an Ashdown and the Elf it's pretty bad. It goes away when I touch the strings so it would appear to be a grounding issue somewhere. I recorded at the start of the year with the valve amps DI and less pedals and everything was silent.
    I'm ruling out my bass as this was recently serviced and had new pots fitted and there is no ground hums when plugged in directly and also ruling out my amps as this is happening with several different amps. Instrument cables have been changed as well as have the cable used for the DI.

    With this in mind can anyone suggest where to start? As far as I can understand it would be one of three issues:
    1) Caline power supply has developed a grounding issue or has a faulty output
    2) Faulty pedal
    3) Patch cable gone dodgy or the pancake connectors being too close?

    I'm using all of the supply sources bar the 12V outlet, so 1 18V pedal, and 8 9V pedals:
    bass > Boss TU2
    Trace Elliot SMX Compressor (18V)
    TC Electronics Sub 'n' Up
    Joyo Tremelo
    EHX LPB-1
    Big Muff Nano now replaced by SA Aftershock
    MojoHand FX Recoil Delay
    DK B3k
    Behringer BD121 > amp

    Patch cables are a combination of home made (have been using these for well over a year before my issue began) and some recently acquired Donner patches. All cables are pancake connections. Perhaps one of my DIY efforts has gone faulty? Can I get a grounding issue if the pedals are too close together? Appreciate this will be a difficult diagnosis without my set up infront of you! If I can nail it down to the Caline then I guess we can discuss a new power source for me!
     
    Last edited: Nov 25, 2018
  2. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Have you lifted the ground on the DI?
     
  3. Yep. The grounding issue is definitely on the pedal board..
     
  4. Vic Winters

    Vic Winters Supporting Member

    Apr 20, 2006
    Western NY
    A few things are causing issues.

    1. The power supply isn't truly isolated which may be causing a ground loop.
    2. The PA is probably running on a different outlet than your amp and pedals which may be causing a ground loop.

    Possible solutions.

    1. Get a truly isolated power supply. (Best solution)
    2. Run everything on the same outlet (Probably not possible)
    3. Try reordering/removing pedals (Not ideal)
    4. Try a 9v battery in the BDI (Worth a shot)
    5. Send the signal to the PA with a transformer isolated DI box. (Worth a shot)
     

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