Tech question - connecting head/cab to combo

[Funkmeister79]

Relative noob here with a question. I have a gig coming up where the backline is a Hartke 120 watt head with 15" Cerwin Vega cab, as well as a 120 watt Hartke 1450 combo amp.

Rather than use one on its own, I'd like to connect the two so I can get loud. I know I'd have to think about ohms when connecting, but what would be the order of operations here (head/cab -> combo, or combo -> head/cab)? Which jacks should I be looking for (preamp out -> power amp in, etc.)?

Thanks!!

[BassmanPaul]

You'll also have to consider phase. If one amp inverts the signal and the other doesn't you'll get cancellation.

Paul

[scottbass]

All you need is another instrument cable (low power 1/4" to 1/4"). Plug your bass into one of the amps. Plug one end of the extra instrument cable into the "preamp out" or the "effects send" of that amp. Plug the other end of the extra instrument cable into the "power amp in" or the "effects return" of the other amp. You will control the gain, EQ, etc. from the amp your bass is plugged into. Use the "master" volume controls on both amps to balance your overall sound. That's it.

What BassmanPaul said about phase cancellation could possibly occur. However, if everything is connected correctly and you don't have a mis-wired speaker cable, everything will be fine.

[Govier966]

plug one's effects send into the others effects return, or something like that. my glx 2x10 was on the verge of dying at a show so i ran the di of my 400 rb into the instrument in of a fender bassman.

[anderbass]

I spent quite awhile gigging a pair of combos and always got my best results running my bass through an A/B/Y pedal, and then into both amps normal inputs.

The problem with linking 2 amps together using the Pre (or Effects) Out jack into the other amps Effects-return is that you'll probably find that each of those 2 rigs need totally different EQ settings to sound their best.