How do I connect two guitar amps together

**Parsnipfingers** · 12-10-2008, 12:12 PM

Hello all,

Up until the weekend I owned two amps, a Cornford Hellcat and a WEM Westminster, both hardwired valve amps. I found myself in the guitar shop over the weekend and remembered reading the Jazz guitar Amps section here when I saw some Roland cube amps. Despite having gone to town to buy things that couldn't have been any less guitar related, I ended up buying the Cube30 they had and ordering another to go with it - I'm not unhappy but I'm still struggling to rationlise how that happened. In my haste I failed to consider the fundamental fact that I have no experience of connecting two amps together

. Could anyone shed some light on the best way to do this with a view to helping me avoid blowing the amps or myself up?

The only pedal I have is a line6 DL4 Delay Modeller. Does anyone know if I can I connect the two amps together using this or do I need to buy something else to do it?

Thanks.

**m78w** · 12-10-2008, 12:22 PM

You might be able to buy a splitter box, or A B box as they are sometimes called. This is a little box that you run your guitar into that has two outputs for both of your amps.

I don't think they cost very much and the store where you bought your amp should carry them.
MW

**mangotango** · 12-10-2008, 02:08 PM

Your Line 6 Delay is stereo out - run one lead to each amp. And sound cool as hell.

**Parsnipfingers** · 12-11-2008, 04:55 AM

I'm loving that

.

Thanks very much.

**mangotango** · 12-11-2008, 09:12 AM

Actually, it may be better than that 'cos some stereo delays give you the ability to ping-pong the repeats between the channels. Which can be quite interesting if the room's big enough to ensure differentiation between the two sides......

**Chito** · 12-11-2008, 02:09 PM

This is the one I use. Inexpensive but works great. Radial BigShot AB-Y true bypass switcher

**Jake Hanlon** · 12-11-2008, 02:12 PM

Running stereo is the best thing ever. My pedal board has stereo outs. I have my office set up for stereo and it is fun to play. Gigs, it's not always practical, but when you can make it happen life is better.

**Parsnipfingers** · 12-12-2008, 01:07 AM

As well as using the stereo out on my Line6, I think I'm going to get me one of those splitter boxes; it looks like a very useful thing to have. The diagrams on that site you linked are excellent for a slow brain like mine!

That ping-pong thing sounds like it could be a lot of fun

. I'm bursting at the seams to get hold of my other Cube now, but the music shop say's they're out of stock at the moment.

You guys rock... erm, jazz I mean

Guys, thank you all so much. There seems to be a warmth in this forum that I have rarely observed online.

**Big Ron** · 02-06-2010, 03:28 PM

I'm glad you brought this up. I'm toying around with sound amp ideas now. I have 400W PA Head and 15" speakers I need to sell and re-engineer with something much smaller. Pretty similar to what you are doing. I really like my Cyber Deluxe and could pick up a matching one for cheaps, but I don't want to haul around two 45 lb amps. I know I would wind up leaving one at home.

I'm thinking of going bananas with a couple of little things like the Fishman SA220 or something. With "something" being two ZT Lunchboxes or Clubs or something.

Ron

**manuelrocks** · 05-08-2011, 02:36 PM

I tried connecting my 2 amps ( a Marshall 250Dfx and a Roland JC-160 ) but it didint go very well , i burned my marshall , but i managed to get it fixed , but what i really want to know is why this happened ? someone have an idea ?

Manuel Brazuna Here !

**pingu** · 05-08-2011, 03:12 PM

How did you wire em up
(you mustn't connect the power out of one amp to the input
of another)

**manuelrocks** · 05-08-2011, 03:15 PM

noo i didint do that , i used a Y-cable , and then connected to the input of each amp

**FatJeff** · 05-08-2011, 03:32 PM

This is what I use. I play through a Fender Blues Jr. coupled with a ZT Lunchbox.

Radial Bones™ Twin-City ABY switcher

**manuelrocks** · 05-08-2011, 03:38 PM

thats cool , how much did it cost ?
but im probably buying a GT-Pro or GT-10 so it might solve the problem..
but do u have any idea why it might happened ?

thanks

**jzucker** · 05-08-2011, 06:27 PM

for two amps, I would advise using a stereo reverb pedal. It sounds *HUGE*

**NiAg** · 05-08-2011, 07:44 PM

Hi M'rocks,

>>> but do u have any idea why it might happened ?

Sure. But it will help if you can identify exactly what happened as part of:

>>>well , i burned my marshall

Also, what were the two amps (model, and roughly when were they made)?

What country (or AC outlet setup)?

What power connectors (any two-prong, thus deeply compromised ground)?

The most common issue with two amps in parallel is a so-called "ground loop". If everything has modern wiring in good order, then the ground loop can result in a hum - caused by the two paths to ground (through each amp and through the grounded connection from one amp to the other via the shield of the signal cord).

But as bad as ground loops are in principle, this is unlikely to have caused serious harm, but,...

Imagine if one of the amps has a "ground" on one side of a two-prong AC cord (as was common for decades). Then consider this "ground" actually being on the hot side of a two prong plug (used to happen all the time). And then you plug a guitar signal cable into the widowmaker amp, which can now possibly have line voltage on the shield of the guitar cable. Then to finish the roast, you plug the cable in to an amp with a grounded input jack,...

At nearly the speed of light you are shunting line voltage directly to ground.

In such a case, an amp's power supply can roast. And with MANY common combinations of guitarist, grounded strings, and cables in hand, you can roast a player as well.

In my opinion, one should absolutely never connect amps in parallel unless you are 100% sure that the power (mains) wiring is absolutely correct on both amps (which is the case on modern production amps). AND, never try to solve any ground loop hum unless you really understand what is meant by a ground loop, multiple paths to ground, and how to safely correct such a condition. (It is not complicated, but errors can result in profound misfortune.)

As usual, all in my opinion.

EDIT: Removed added comments on ground loops.

**helios** · 05-09-2011, 01:14 PM

Originally Posted by Chito

This is the one I use. Inexpensive but works great. Radial BigShot AB-Y true bypass switcher

I'll second the Radial AB-Y! It also has a phase switch (to match amp polarities with each other), and a tuner out jack. You can also use it in reverse and run two guitars into one amp!