Marshall Emulated Line Out Problem

  • Thread starter Thread starter c0d3wr1t3r
  • Start date Start date
C

c0d3wr1t3r

New member
I am a newbie here so if I posted this in the wrong area I apologize. Here is my problem.
I have a Marshall TSL 2000 and am trying to use the emulated line out to run into my computer for recording.
When I plug the amp to the PA I get a fairly loud constant humming sound.
The ELO plug is XLR and the PA accepts both 1/4" and XLR jacks. I tried both with the same outcome.
I have the AMP on standby without a guitar een plugged in, either way I get the same humm.
I looked in my amp manual and it has a diagram for the line out XLR connections. Do I need a special cord for this? Any help will be greatly appreciated.
THanks,
Joe
 
You are getting a ground loop. Is everything grounded properly? Is everything on the same circuit?
 
ocnor said:
You need to lift the ground of the Marshall with a power cord adapter like this http://shop.store.yahoo.com/cinemasupplies/grliadco41.html Your amp will still be grounded through the line out to the PA.
Click to expand...
It is foolish and dangerous to lift the ground. If the place is wired incorrectly, you could get zapped or fry your amp. The ground pin is a saftey device.
BTW if the wiring was in great shape, there would be no hum.
 
Farview said:
It is foolish and dangerous to lift the ground. If the place is wired incorrectly, you could get zapped or fry your amp. The ground pin is a saftey device.
BTW if the wiring was in great shape, there would be no hum.
Click to expand...
When a ground loop exists it means that there is more than one path to ground. By lifting the ground on the amp you are not left without a ground you are just eliminating one of the paths. As long as the PA has a ground anything that you plug into it will be grounded as all cords have a tip and a ground.
After more than 25 years of live sound gigs the best way I have found is to ground one piece of gear such as the mixer and lift the ground of everything else that connects to that piece. That way you only have one path to ground and no hum.
 
And what happens when the shortest path to ground shifts from the Marshalls DI to your mouth on the sm58. Lip lightening!
Besides, if something catastrophic happens inside the amp, do you really want it bleeding excess current into your mixer?
25 years ago I used to do that too, it was stupid but we didn't know any better. Not to mention the fact that you could actually pull up on a club without 3 prong plugs in the '70s. The ebtech thing is good, a DI box will work, or just mic the damn cabinet already.
 
Farview said:
And what happens when the shortest path to ground shifts from the Marshalls DI to your mouth on the sm58. Lip lightening!
Click to expand...
Most people don't stand on a cement floor in their bare feet while they are playing because thats the only way that could happen. It's called a "star grounding pattern" and it is used by people everywhere in studios as well as live sound.
 
You must log in or register to reply here.
Back
Top