Become a Supporting Member


Go Back   The Gear Page > Instruments > Luthier's Corner: Guitar & Bass Technical Discussion

Reply
 
Thread Tools Display Modes
  #1  
Old 01-21-2005, 07:17 AM
matei
Guest
 
Posts: n/a
Sever buzz when running 2 amps w/ stereo pedal

Hello!

I am trying to run two amps off of a stereo Chorus pedal (Boss CE-2). However, as soon as I connect one of the amps I get a horrible buzz - like bad grounding.

I've tried switching cables, amps, running the pedal off battery instead of mains, even changing the pedal for a different one - still the buzz persists.

By themselves the amps are quiet. By itself, the pedal is quiet. Together they are buzz city!

Any ideas what this could be?
Reply With Quote
  #2  
Old 01-21-2005, 08:14 AM
Jimmy Somma Jimmy Somma is offline
Member
 
Join Date: Oct 2004
Location: Gladstone, NJ
Posts: 154
The problem doesn't lie with the pedal, It's with your amps. You're creating what's called a ground loop. Whenever you run multiple amps, only one of them needs to be grounded at the outlet. To fix this, use a three prong to two prong adaptor on the power cord of one of the amps. This should eliminate your hum problem.

www.sommatone.com
__________________
Jimmy Somma
Sommatone Amplification
Hear the difference...
www.wiser-time.com
904.438.8663
Reply With Quote
  #3  
Old 01-21-2005, 08:45 AM
Randy Randy is offline
Supporting Member
 
Join Date: Sep 2002
Location: CT
Posts: 3,606
An even better solution is to use a splitter with transformer isolated outputs, thereby eliminating the danger of lifting the ground on one of your amps.

I use the Axess BS-2 which has the added benefits of a buffered output and a phase reversal switch. Highly reccomended.
Reply With Quote
  #4  
Old 01-21-2005, 08:06 PM
Jimmy Somma Jimmy Somma is offline
Member
 
Join Date: Oct 2004
Location: Gladstone, NJ
Posts: 154
Technically you're not lifting the ground because the amp is getting grounded through the guitar cable.

www.sommatone.com
__________________
Jimmy Somma
Sommatone Amplification
Hear the difference...
www.wiser-time.com
904.438.8663
Reply With Quote
  #5  
Old 01-22-2005, 12:20 PM
hipfan hipfan is offline
Supporting Member
 
Join Date: Nov 2002
Location: Evanston, IL
Posts: 2,183
One of THESE should take care of your problem. I use one to cure ground looping at my rehearsal space. Works like a charm.
Reply With Quote
  #6  
Old 01-28-2005, 07:11 AM
TonyV TonyV is offline
Senior Member
 
Join Date: Aug 2002
Posts: 622
try switchbone

http://www.zzounds.com/item--RADJX2
Reply With Quote
  #7  
Old 02-16-2008, 05:25 PM
Shawn S. Shawn S. is offline
Senior Member
 
Join Date: Nov 2007
Location: Kansas City
Posts: 439
I just experienced running amps in stereo for the first time, along with the ground loop I noticed that my volume pedals pot sounded scratchy like it was bad, but with an amp out of the loop the scratch goes away. The same thing happens on my guitar's volume knob too - disappearing when an amp is out of the loop (switched off).

Will something like the Hum-X fix both the ground loop hum and also the scratchy pots?
Reply With Quote
  #8  
Old 02-16-2008, 06:15 PM
walterw walterw is offline
Gold Supporting Member
 
Join Date: Oct 2006
Posts: 14,808
that scratchy sound indicates some dc voltage on the pot. a cheap fix for the ground loop issue that sometimes works is to get or make a ground-lift signal cable, with the ground connection snipped on one end, and use that on one of the amps.
__________________
Walter Wright
Guitar Repair Gnome
Alpha Music, Va Beach
Reply With Quote
  #9  
Old 02-16-2008, 06:17 PM
Shawn S. Shawn S. is offline
Senior Member
 
Join Date: Nov 2007
Location: Kansas City
Posts: 439
When you remove the ground loop through any means (Hum X, snipped cable, A/B selector) does it also remove the scratch?
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 02:31 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2013, Jelsoft Enterprises Ltd.
Copyright ©1999-2013, The Gear Page, LLC, Brian Scherzer
All rights reserved.
Header Graphic by NetThink 21