Connect two amps

[Terry Srader]

Want to use effects processor with 2 amps. Can i connect my 2 amps together?

AMPS: NV400 and S400

how is this done?

[Dennis Wallis]

Use a guitar cord (shortest you can get by with),come out of the PRE AMP OUT of the main amp ( first one) into the POWER AMP IN of the second amp. The tone controls,etc. will control both amps.The second amp will just use the power amp.

[Mike Perlowin]

I split the signal with a stereo chorus and ran a line from each output of the chorus to each amp.

[Jim Sliff]

I also prefer the method Mike uses (or an A/B/A+B box), as you get full use of the different EQ sections of each amp (and the EQ each power amp was matchhed with) by running through the entire amp.

You generally get much richer sound that way as there will be a more significant difference in the harmonic content, plus you can set one amp tweaked for highs and one for lows, or one with mids enhanced and one with scooped mids - gives you a lot more options. You can use a stereo chorus, stereo delay....stereo anything. Just run your processor ahead of the effect used as a splitter, keep the effect turned off and it'll split the signal for you.

One question though - many "effects processors" (meaning multi-effect units) are stereo anyway - if so, just hook it up with the L and R outputs and you're done.

[Stephen Gambrell]

I agree with Mike and Jim. A lot of effects have a dry out, if not true stereo outputs.
Or, you could do it like Jimi...

[David Doggett]

Dennis' method slaves the 2nd amp to the first amp, and bypasses the preamp EQ controls of the 2nd amp. Only the preamp EQ controls of the 1st amp are in use.

Mike and Jim's method splits the signal and runs it to both amps, including the preamp section of each amp. Thus, the EQ controls of each amp are in use.

There is also an old "jumper" method where you run the signal into one amp, and jumper a cord from the 2nd input of that amp into the input of a second amp. I have never been clear on why or how that works.

[George McLellan]

David, I'm not sure if this was your question, but this is how I do it with a NV112 & 63 Fender Pro (it'll work the same with a Twin Reverb or any other Fender tube amp).

Out of the NV112 pre to the number 2 input of the Fender, then I have full control over what ever I need.

Geo

[Jonathan Shacklock]

Do any of these methods benefit from lifting the ground on one of the amps, and if so does it make a difference which amp is grounded in terms of safety?

[Rick Abbott]

Come-on, don't you realize that an occasional shock lets you know that you're alive?! And gear paranoia is fun and rewarding? I used to get a reasonable shock with a 63 Princeton and a Real Tube pedal. I found ways to not touch anything metal (I was playing hard blues anyway) for a whole decade when setting up. OCD fun

[Jim Sliff]

Do any of these methods benefit from lifting the ground on one of the amps,

No.

If you have to lift the ground there is a problem that needs to be solved in terms of safety. A ground lift is a quick-and-dirty method some people use to reduce hum, but I strongly advise against it. Find the problem and solve it. A ground lift, seemingly done correctly, can turn YOU into the ground. Not a good idea.

[Justin Griffith]

I have always had to lift the ground on 1 amp when using 2. Can anyone explain? Everyone I know has to do the same.

[Jim Sliff]

Justin - If that's happening there's usually a polarity problem with either one of the amps or they are being plugged into seperate power sources where polarity is reversed. AC power, contrary to what many think, has polarity - that's why modern extension cords have a large and small lug (and extension cords with equal-size lugs should be thrown away). It's not unusual for an amp with a 3-prong plug to be wired backwards - the reason you often see the ground plug chopped off; so the cord can be reversed.

If everyone you know ids having this problem, I venture guess everyone you know does not check the wall plug they are using as a source with a circuit tester - which should be an esssential toolkit item for every player. About $7 buys you a lot of safety. But if you check and find reversed wall wiring - call an electrician. If it's reversed in the amp, it's a 15-20 minute job for a tech. There is NO reason for a ground lift to be used that can't be fixed with a combination of modern, properly grounded amps.