driving more than one amp from guitar.. hey Fig

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eedude
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driving more than one amp from guitar.. hey Fig

Post by eedude » Sat Mar 12, 2011 6:09 pm

those of you that are driving more than one amp from your guitar, what are using to interface between the guitar and the amps?

I'm trying to run two amps just using a Boss stereo chorus, but I get a ground loop....
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Mattfig
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Re: driving more than one amp from guitar.. hey Fig

Post by Mattfig » Sat Mar 12, 2011 6:19 pm

eedude wrote:those of you that are driving more than one amp from your guitar, what are using to interface between the guitar and the amps?

I'm trying to run two amps just using a Boss stereo chorus, but I get a ground loop....
Well, my solution to run multiple preamps and such is a Voodoo Labs GCX Guitar Audio Switcher along with a Ground Control Plus pedal....There's one on rig-talk right now for 600...I know it's pricey but it's awesome....
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eedude
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Post by eedude » Sat Mar 12, 2011 6:28 pm

thank fig, yeah.. big bucks! fig once you see my rig you're gonna cry :twisted:
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Re: driving more than one amp from guitar.. hey Fig

Post by SacredGroove » Sat Mar 12, 2011 6:28 pm

Mattfig wrote:
eedude wrote:those of you that are driving more than one amp from your guitar, what are using to interface between the guitar and the amps?

I'm trying to run two amps just using a Boss stereo chorus, but I get a ground loop....
Well, my solution to run multiple preamps and such is a Voodoo Labs GCX Guitar Audio Switcher along with a Ground Control Plus pedal....There's one on rig-talk right now for 600...I know it's pricey but it's awesome....
Which is cool, because the GCX has a built in buffer, before the loops.
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Mattfig
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Re: driving more than one amp from guitar.. hey Fig

Post by Mattfig » Sat Mar 12, 2011 6:57 pm

SacredGroove wrote:
Mattfig wrote:
eedude wrote:those of you that are driving more than one amp from your guitar, what are using to interface between the guitar and the amps?

I'm trying to run two amps just using a Boss stereo chorus, but I get a ground loop....
Well, my solution to run multiple preamps and such is a Voodoo Labs GCX Guitar Audio Switcher along with a Ground Control Plus pedal....There's one on rig-talk right now for 600...I know it's pricey but it's awesome....
Which is cool, because the GCX has a built in buffer, before the loops.
Plus, Sacred Groove talked me thru my first steps into MIDI and now I am an addict....I can't believe I always avoided using it....Life is easy with it once it's all programmed...

And eedude...Uh oh...I might need to add that other RM4 to keep up with the Joneses...???...Can't wait to see it bro!
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crankyrayhanky
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Post by crankyrayhanky » Sat Mar 12, 2011 7:12 pm

use this on 1 of the amps,problem solved:

http://www.ebtechaudio.com/humxdes.html

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Post by Rod » Sun Mar 13, 2011 3:17 am

RAY'S SOLUTION IS THE BEST AND SAFEST..The emergency version is to lift the ground on 1 of the amps....You use those grey 3 into 2 connectors that go on the end of the power cord..Cost about 80 cents....but your 1 amp is not grounded..

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Post by bduersch » Sun Mar 13, 2011 7:21 am

Try to find an Axess Electronics BS1 buffer... great piece of kit which has an isolated output (for ground loops) as well as a phase switch (always a risk when playing with 2+ amps).

I've tried the Ebtech hum eliminator... have mixed feelings on it... it is a "miracle device" for killing ground loop hum, but in some applications I've found it to be a tone suck. Probably won't know for sure until you try it yourself.

--B

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Post by m0jo » Sun Mar 13, 2011 7:51 am

Rod wrote:RAY'S SOLUTION IS THE BEST AND SAFEST..The emergency version is to lift the ground on 1 of the amps....You use those grey 3 into 2 connectors that go on the end of the power cord..Cost about 80 cents....but your 1 amp is not grounded..
In other words: NEVER do this..

It's just not safe, just run a buffer with ground lift in line to one of the amps, that's even easyer.
Or something like this: http://pro-audio.musiciansfriend.com/pr ... sku=180014

There are stacks of these types of boxes.
Just run them in the signal path to one amp and you're golden.

Otherwise there's the Lehle P-Split, specially for this application.
Or the Gig-rig buffer pedal. I believe the Toadworks Banana buffer also does buffered splitting :) (and ground lifting)

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Post by crankyrayhanky » Sun Mar 13, 2011 9:38 am

RAY'S SOLUTION IS THE BEST AND SAFEST
I've never had this said about me, much less in CAPS, lol...my ideas are often described as Bad & Dangerous.

Regarding the "tone suck" issue, how could that be? It's basically converting power, so only 1 amp is grounded and the amp in the Ebtech is a safer version of a 2 prong? IDK, I never heard tone suck with this method.....though I haven't used it in a while, I used to run (2) rm100s but now I'm down to (1)

eedude
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Post by eedude » Sun Mar 13, 2011 11:00 am

Rod wrote:..You use those grey 3 into 2 connectors that go on the end of the power cord..Cost about 80 cents....but your 1 amp is not grounded..
$0.80 is too much, i'd just cut the third prong off the IEC power cable :shock:
just kidding... yeah i know that's all bad. Some of the boxes mentioned must have isolation transformer... else it wont break the loop. ... Crankyray's suggested product does not go in the guitar path, which makes it very attractive...

all good ideas, keep 'em coming... i've goat an idea or two i'm gonna try today...
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Post by crankyrayhanky » Sun Mar 13, 2011 11:10 am

in the past I've had ground switches on amps that seemingly did nothing. However, the ebTech is very effective for the 2 amp setup
before ebtech: BIG hum in 1 amp
after: Zero Hum (or at least back to normal for a hi gain amp)

bduersch
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Post by bduersch » Mon Mar 14, 2011 4:41 am

crankyrayhanky wrote:
Regarding the "tone suck" issue, how could that be? It's basically converting power, so only 1 amp is grounded and the amp in the Ebtech is a safer version of a 2 prong? IDK, I never heard tone suck with this method.....though I haven't used it in a while, I used to run (2) rm100s but now I'm down to (1)
You're right... I wasn't thinking about the Hum-X (which interacts with the power line)... I was thinking about the Hum Eliminator ( http://guitars.musiciansfriend.com/prod ... sku=150450 ) when I wrote that. The Hum Eliminator works miracles but since it interacts with the audio signal can cause tone suck.

--B

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Post by Mike P » Mon Mar 14, 2011 7:17 pm

This the finest switching product on the market, bar none:

http://guitars.musiciansfriend.com/prod ... D=26018792

Radial Switchbone. It'll meet all of your needs and then some.
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Egnater / Randall Modular Amps

Post by kc2eeb » Tue Mar 15, 2011 7:31 pm

Thoughts about Ground Lift, Ground adapters and loops.
First, are both amps plugged into the same socket?
Second, if you lift the ground from one amp (using a ground adapter)
and you have the guitar cable going from one amp to another, it is still
grounded PROVIDED that the shield of the guitar cable is connecting the two chassis. That's why the RM4 has a ground lift switch. It's to eliminate ground LOOPS, not to disconnect the ground connection.
It's easy to check. With all the cables plugged in, use a multimeter to check for continuity between the chassis ground of both amps. If you lift the ground from ONE amp and it shows continuity between the amp chassis, as long as
ONE AC cord is connected to ground, you've got it.
The idea is to have ONE path to ground.

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