pedal not working with mixing console

Discussion in 'Live Sound [BG]' started by boilingTheDead, Mar 11, 2020.

  1. boilingTheDead


    Oct 15, 2018
    We have a YAMAHA MC1602 in the rehearsal room and Im succesfully using the 1/4" Input. The signal gets to an amp and drives the PA -works perfecty.

    As soon as Im using any pedal, the signal is dead and a very loud hissing (I guess 80Hz) noise appears.


    (not the cable, not the pedal, not the bass)
  2. jimfist

    jimfist "Cling tenaciously to my buttocks!" Supporting Member

    Mar 28, 2011
    Boston, MA (USA)
    what pedal are you using? Do you have any other pedals to try to see if it does the same thing? I can't imagine why this would happen if the pedal is working properly.
  3. boilingTheDead


    Oct 15, 2018
    VTbass DI, ampeg optocomp
    both light up, does the same with both pedals.
  4. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    1964 Audio artist, Fractal Audio Beta Tester
    1/4" inputs are usually LINE level inputs. You're probably hearing low signal noise floor!
    Try running an XLR (mic) cable from the VTBass into the console.
    Turn the trim/gain all the way down first, and slowly increase it as you play until you get a good signal level.
    Last edited: Mar 12, 2020
    kittywithabanjo and Mushroo like this.
  5. boilingTheDead


    Oct 15, 2018
    but why does the noise floor not appear when im using the 1/4 imput without a pedal?
  6. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    1964 Audio artist, Fractal Audio Beta Tester
    Are you using an active bass?
  7. boilingTheDead


    Oct 15, 2018
  8. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    1964 Audio artist, Fractal Audio Beta Tester
    hmm.. OK. tough to diagnose over the interweb.
    The FOH guy in me will ALWAYS recommend running an XLR from DI to console when available.
  9. turcmic


    Jul 30, 2006
    Montreal, QC
    That’s the best recommendation : you have a DI, you use the DI and save on the troubleshooting.
    s0c9 likes this.
  10. Jon Mush

    Jon Mush

    Jun 3, 2015
    Winnipeg, MB
    Those were Hi/Z inputs. And the gain pot is after it, so you may have decent success. The VT still might give you better signal to noise, given the output is likely higher.

    XLR cables are inherently better because they cancel out any noise picked up by the cable. I would rather use that as well.

    Adding the pedal, you’re needing to add a cable. Are you sure there’s not a fault in a cable? Or there may be a grounding issue (loop). Are you powering the unit via the same power source? Again this is where DIs are usually great, there’s a ground lift, which may alleviate the issue, but sometimes active DIs are not perfectly able to get rid of all the ‘rizz’ on the line, and you need a passive (transformer) DI with a ground lift to accomplish that task.
  11. boilingTheDead


    Oct 15, 2018
    Ok but why is the sound complete dead (not just noisy) when the pedal is involved?
  12. Jon Mush

    Jon Mush

    Jun 3, 2015
    Winnipeg, MB
    wow. I must have misread your post. Sorry.

    Yeah, if you’re sure all the cables are good, and you’ve plugged the whole lot into an amp to verify? Then I’m stumped.

    Insertion of the pedal isn’t adding a lot of gain? The only thing I can think of is that it’s freaking out the console pre in some way. Did you try popping in the pad? Try other console channels?

    That console is 30-40 years old, isn’t it? Things can start to go squirrelly.

    Apologies for the no help.
  13. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    try that pedal into something else (like a regular amp) to make sure the pedal itself and all the cables involved are working
  14. 80hz? More likely 60. That's a hum not a hiss.
  15. mrufino1


    Aug 2, 2005
    Nutley, NJ
    Never mind... posted the wrong info. I just looked up that mixer and the 1/4” inputs do say they can take an instrument level signal. There must be something missing in the description (not your fault, you can only describe what you know is happening or you wouldn't be asking), hard to solve when not in the room.
    Last edited: Mar 16, 2020
  16. SteveIII


    Jul 11, 2019
    Oshawa Ontario
    Is the phantom power switch on? I was reading the manual and it looks like the phantom power is also connected to the tip and ring of the 1/4 input. That might upset the pedals but not your passive bass. Also are you using trs cable or just ts?

    Attached Files:

    s0c9 likes this.
  17. thumbknuckle

    thumbknuckle In Memoriam

    May 23, 2012
    Westfield, MA
    I had the same thought. The block diagram makes it look like phantom power is connected to the 1/4" inputs but there is text somewhere which says they are not.

    Making sure phantom power is off is certainly worth trying.

    This is a weird one.
    s0c9 likes this.
  18. hbarcat

    hbarcat Supporting Member

    Aug 24, 2006
    Rochelle, Illinois
    Are you plugging into the insert jack instead of the line in jack?


    Sorry, I think I misunderstood you at first.

    I see now that you're getting a food signal when you're going straight to the board from the bass but adding a pedal kills the bass signal but adds noise.

    If you've already swapped cables and used 2 different pedal and tried different channels and also made sure phantom power is off then I'm stumped.
    Last edited: Mar 22, 2020
    walterw and s0c9 like this.
  19. boilingTheDead


    Oct 15, 2018
    Ok, Its kind of impossible to go further now because I cant use the room anymore (due to corona)… Anyway, thank you a lot for your responds and yor time! Why would they connect the phantom power to the 1/4" inputs? Also, where is that phantom power switch located? I havent even seen it, so it could be the issue.
  20. el murdoque

    el murdoque

    Mar 10, 2013
    The very first guess is that something really stupid is happening, like you have the cables mixed up (Input&output). The other guess might be something to do with the electricity in that place.
    Or you've blown both pedals with a faulty power supply so they show the same error.
    I'd check every single component.
    Does the thing happen with the pedal connected, but not active?