ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: hiss/fuzz in a few channels  (Read 3995 times)

Kevin Drysdale

  • Newbie
  • *
  • Offline Offline
  • Posts: 3
hiss/fuzz in a few channels
« on: August 19, 2011, 06:31:01 PM »

Hi!  I have a strange problem that I'm not sure how to troubleshoot anymore, or a potential fix.  I have a few channels have a hiss.  This is what I have tried so far:
- guitar plugs into channel 1 and 2.  Channel 2 has hiss, channel 1 does not
- channel 3 (a vocal mic) has no hiss as well
- unplugged input from channel 3 and plugged it into channel 2.  Hiss is gone from channel 2 and moved to channel 3 (not the mixer channel)
- guitar pedal has 2 DI outputs and regardless of how I use the outputs I always have hiss only on channel 2.  Left output to channel 2 makes hiss, Right output to channel 2 makes hiss.  Left output to channel 1 makes NO hiss, Right output to channel 1 makes NO hiss.

Initially I thought one of the DIs were bad, but that last step baffles me.  This is the signal path of the guitar:
Guitar plugged into FX pedal (Digitech - don't know the model off hand) -> XLR outputs of pedal (ground lift activated) to Yamaha 01v96 mixer.

While typing this my next thought would be to get some long XLR cords and plug in directly to the mixer rather than our installed wire.  If anyone here has any other thoughts it would be greatly appreciated.
Logged

Ryan M. Fluharty

  • Newbie
  • *
  • Offline Offline
  • Posts: 31
Re: hiss/fuzz in a few channels
« Reply #1 on: August 19, 2011, 09:41:46 PM »

I know this may sound simple, but have you checked the eq settings on channel 2, especially the "hi" knob?  My experience has been that DI instruments, especially when using less than perfect DIs, tend to hiss more than microphones.

Also, I didn't really understand the part in your post that says "unplugged input from channel 3 and plugged it into channel 2.  Hiss is gone from channel 2 and moved to channel 3 (not the mixer channel)."  Are you talking about your snake inputs?
Logged

Frank DeWitt

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1010
    • LBP DI Box
Re: hiss/fuzz in a few channels
« Reply #2 on: August 19, 2011, 09:45:53 PM »

I read this 4 times and my head hurts.

What does this mean?  (not the mixer channel)
I think you have a bad installed wire  (ch 2) but that is a guess at this point.

Unplug all the inputs from  mixer (At the mixer)
Plug a mic into each input and check it.
If none hiss, then the mixer is OK.

Now put everything back.
The hiss is back on Ch 2
Now reverse Ch 1 and Ch 2 at the mixer. does the hiss move?
Now reverse ch1 and ch 2 at the platform does the hiss move?

If it doesn't at the mixer and does when switched at the platform, it is a ch on your installed wire.

Frank



Logged
Not to Code

Brad Weber

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2208
  • Marietta, GA
Re: hiss/fuzz in a few channels
« Reply #3 on: August 20, 2011, 08:54:19 AM »

I read this 4 times and my head hurts.

What does this mean?  (not the mixer channel)
I had the same problem.  Are what you are calling channels actually the input labels for the cabling path?  Is "Channel 1" actually the stage input labeled 1?


When comparing signals running into multiple channels on the mixer you need to make sure that the gain/trim, mic/line, pad, and EQ settings are the same for those channels.  The XLR output on some of the Digitech pedals is apparently a maximum +16dBu line level signal so it seems like in the one case you were comparing a mic input to a line input.


It sounds like it could be a problem with the installed cabling but it could also be that "Channel 1" is run into a mixer channel configure for line level while "Channel 2"  is run into a mixer channel setup for a mic input.
Logged

Kevin Drysdale

  • Newbie
  • *
  • Offline Offline
  • Posts: 3
Re: hiss/fuzz in a few channels
« Reply #4 on: August 20, 2011, 01:55:52 PM »

Sorry to cause confusion.  I will explain in more detail what "unplugged input from channel 3 and plugged it into channel 2.  Hiss is gone from channel 2 and moved to channel 3 (not the mixer channel)." means. :)  On the mixer I swapped the wires for channel 2 and 3.  The hiss moved to channel 3 and there was no hiss on channel 2.  That tells me that there is nothing wrong with channel 2 on the mixer.  I have heard of some mixers having channels go "bad" and creating noise so I was confirming that.  Now to go over a few of the replies...

I call a channel each input into the mixer.

I have the same EQ settings for channel 1 and 2 (both guitar inputs) and hiss only shows on channel 2.
Quote
Now put everything back.
The hiss is back on Ch 2
Now reverse Ch 1 and Ch 2 at the mixer. does the hiss move?
Now reverse ch1 and ch 2 at the platform does the hiss move?

If it doesn't at the mixer and does when switched at the platform, it is a ch on your installed wire.
I did reverse Ch 1 and Ch 2 at the mixer - the hiss did not move.
I also reversed ch1 and ch2 at the platform and can't remember if it moved.  I seem to think it didn't and that was why I started trying to confirm that the mixer was good by plugging a mic into the mixer ch2 which made the hiss go away.

One other thing I just tried was I disconnected the Digitech pedal and the hiss left from Ch2.  So...I'm guessing there must be something wrong with the pedal's XLR outputs. Thanks for the help, and sorry for the confusion in my original post.
Logged

Mac Kerr

  • Old enough to know better
  • Administrator
  • Hero Member
  • *****
  • Offline Offline
  • Posts: 7551
  • Audio Plumber
Troubleshooting procedure
« Reply #5 on: August 20, 2011, 06:17:34 PM »

One other thing I just tried was I disconnected the Digitech pedal and the hiss left from Ch2.  So...I'm guessing there must be something wrong with the pedal's XLR outputs. Thanks for the help, and sorry for the confusion in my original post.

Whenever you are troubleshooting any problem you need to break it down into simple blocks and follow a logical path. The first thing to do is start at the source. Unplug the source and see if the problem changes. If yes, you have found your problem. If not, move to the next connection point in line and try unplugging there. If it changes there, you have narrowed the problem down to between the source and the next connection point. Move through the whole signal path that way till you can isolate the problem. Randomly changing channels is only going to get you confused.

Mac
Logged

ProSoundWeb Community

Troubleshooting procedure
« Reply #5 on: August 20, 2011, 06:17:34 PM »


Pages: [1]   Go Up
 



Site Hosted By Ashdown Technologies, Inc.

Page created in 0.023 seconds with 19 queries.