running two amps and eliminating hum

Chickenwings

Chickenwings

Alnico 6/8
Hi - i have tried running my fender and marshall amps together, but if i try to connect the two using a stereo pedal like a chorus or a delay i get a loud hum. Neither amp has a parallel input so its gotta be stereo. i get the same buzz using any different configurations of line out/fx outs or whatever.
Is there any way i can run them together and get rid of the hum?
I would like to have the stereo option for the delays (deja vu), but any solutions would be good. Wolud a radial a/b box fix it?
 
Re: running two amps and eliminating hum

Plugging both amps into the same A/C source? If you've got them plugged into outlets on two different breakers (or circuits) you'll get a ground loop which causes bad hum.
 
Re: running two amps and eliminating hum

im running them both on the same powerboard, but i have tried separate wall sockets too. The fender is running on a transformer cos its a US model running 110v, so the converter takes 240v from the wall and means i did not have to modify the amp to use australian voltage. The Marshall is a 240v amp so it needs no transformer.
 
Last edited:
Re: running two amps and eliminating hum

Sounds like you need an amp ABY pedal of sorts that has a ground lift on it. Voodoo labs makes a really nice one that you can switch between 4 amps with. Morley makes a 2 and 3 amp switcher if you're looking for something a little cheaper.
 
Re: running two amps and eliminating hum

This is really one of the main reasons I sold a bunch of good amps I was trying to use in stereo, and going for a Bogner XTC/212 as a main rig. I want a Twin, Plexi, modded Marshall tone, and that's what I have now. I got sick of rolling the dice anytime I set up a 2 amp rig, and suffering hum much of the time.

Lifting the ground on one amp is the old school way of doing it, and I suppose it works, but I experience so much bad electricity that I just don't do it anymore.

And it's too bad because many times a stereo rig sounds amazing. I wish amps still had the polarity switch on the back.....the one that confused everyone as to what it actually did. That's what those were for.
 
Re: running two amps and eliminating hum

The Radial ABY will do it easily. I have used mine extensively. Last summer I even had three amps going (my Shiva and Traynor heads running stereo out of my TC Nova System - out of one side of the ABY, and my Fender Twin out of the other side). The ground loop and hum switch combinations have always been able to get rid of the noise issue for me.

Here's another idea to try if possible. Right now I'm slaving my XTC into my Traynor. I am not using any kind of ABY or ground lift, etc. I get the advantage of a stereo type of thing, but with the tone of the Bogner in both half stacks. I run a regular guitar cable out of the line-out of my XTC, into the power amp in of my Traynor head. Each head powers a 4X12 cab. A major advantage of this setup is that all the channel switching is done on the Bogner. In the past, I got pretty busy tap dancing with several amp switching pedals. To top it off, the Traynor has an adjustable volume boost. And that boost happens to work even with the Traynor being slave to the XTC (because of the fact that it's power amp based). So I can really kick it up for solos. A pretty awesome setup for big outdoor gigs.
 
Re: running two amps and eliminating hum

I use Lehle pedal for this task. I used to used a Radial ABY, but it still had some humming to it.

This information is from the Lehle manual...

The Lehle Dual SGoS sends the signal via gold-plated relays to outputs A, B or T .Outputs A and B can feed 2 different amps simultaneously since the signal paths are electrically isolated through the high end transformer Lehle LTHZ - this eliminates humming loops completely. In this case the pots allow you to lower the output signal for A and B separately. Output T can be used for a tuner or a 3rd amplifier. Both inputs can be routed stereo to the outputs A and B . In addition to that the Lehle Dual SGoS provides gold-plated phase-reverse and ground lift switches. The Lehle Dual SGoS can be controlled and synchronized with other Lehle SGoS Switchers via MIDI.

Output A is electrically isolated from Output B by the Lehle LTHZ high-end transformer - so hum loops are impossible, even if A and B are switched on simultaneously.

I purchased it here last year.

http://www.guitarpedalstore.com/gui...Lehle-Dual-Amp-Switcher-with-LTHZ-Transformer
 
Last edited:
Re: running two amps and eliminating hum

I've been using this ABY with my stereo amp rig for awhile with no problems, no noise, no hum whatsoever. Plus it has buffer, ground lift, phase/polarity reversal, and Drag load correction. Less than 1/2 the price of the Lehle
 
Re: running two amps and eliminating hum

i run a Peavey 3120 in stereo with a 5150 each into their own Splawn 4x12 and this Radial Bones Twin City A/B/Y works perfect having a lift to get rid of hum, a phase switch to fix any out of phase issues and a drag control which acts like an adjustable buffer if you need one.

http://www.tonebone.com/bones-twincity.htm
 
Re: running two amps and eliminating hum

XSSIVE said:
i run a Peavey 3120 in stereo with a 5150 each into their own Splawn 4x12 and this Radial Bones Twin City A/B/Y works perfect having a lift to get rid of hum, a phase switch to fix any out of phase issues and a drag control which acts like an adjustable buffer if you need one.

http://www.tonebone.com/bones-twincity.htm
Click to expand...
I'm using the same thing to switch between a Bumbox Cielo and EAST Studio 2. Works fine -- BUT -- requires it's own 12V power supply with tip Positive, not Negative, which can be a pain if you have a power supply for your pedal board.
 
Re: running two amps and eliminating hum

I run two amps at home & I elected to use a loopmaster A/B/Y. It works fine, but it does have some ground loop hum. What I did is put a Humx on each amp and that killed about 85% of the hum. Now considering what I spent...... well I was trying to avoid using a Lehle switch, but I probably should have. Tha loopmaster was about 80.00 & the Humx was about 65. each. IF I had bought the Lehle the ground loop hum transformers are built into it and it kills all the hum. It also depends on what or how you use your amps. If you plan on running both amps at the same time then you need an A/B/Y, but if you are going to be playing through on at a time a simple A/B will be fine. I rarely use both at the same time, but I can if I choose to. The way I set them up is I have a Bogner Shiva which has an effects loop. I have a Chorus and delay running through the loop and a TS9 going straight in. Then that cable goes to one side of the A/B/Y. On my other amp which has no loop I have a series of effcts going straight in, then that cable goes to the other side. From the A/B/Y I then go to my Wah and tuner, to guitar. Its simple, clean and very effective.

Here is a look at the Lehle switch.

http://www.guitarcenter.com/Lehle-D...-i1368096.gc?source=4WFRWXX&CAWELAID=90013794
 
Re: running two amps and eliminating hum

i love the Radial pedals for this... i have the small one right now but want the full sized one...
 
Re: running two amps and eliminating hum

TwilightOdyssey said:
I'm using the same thing to switch between a Bumbox Cielo and EAST Studio 2. Works fine -- BUT -- requires it's own 12V power supply with tip Positive, not Negative, which can be a pain if you have a power supply for your pedal board.
Click to expand...

it works from 9v-12v. i actually power mine with a 9v dunlop power supply from a wah. no problems at all. it even says on the site "standard 9v power supply operation" so any boss, MXR or dunlop power supply with work so will a PP2+ or similar.
 
Re: running two amps and eliminating hum

I forget where I read this, I BELIEVE it was under a review for the George Lynch pedal where you can hook up three amps, but sometimes something as simple as some kind of insulation inside the pedal to keep something from touching the chassis can eliminate the hum--according to the review I read. I believe it was either on Musician's Friend or Harmony Central. Maybe some of the more technical guys can comment on this as I'm an electronics fool.
 
Re: running two amps and eliminating hum

All this is about is disconnecting ground. Just have one cable with the shield on one side not connected to the mass of the plug for these cases. Snip. Done.
 
You must log in or register to reply here.

Similar threads

FuseG4
Npd: two in one ambient reverb
Replies
1
Views
32
Mincer
Mincer
devastone
FS: Boss GT-1000 with Boss Gig Bag
Replies
0
Views
50
devastone
devastone
Bfeeney
Tweedy speaker distortion problem
Replies
12
Views
420
ehdwuld
ehdwuld
R
Replaced bridge PU on RG470 and getting a hum
Replies
9
Views
368
Artie
Artie
Hiwatts and Gibsons
Incoming NAD. Gonna be my last purchase for a long time.
Replies
10
Views
420
Ascension
Ascension
Back
Top