USing other amps as cabs?

yes. if you come out the speaker out of the amp your using , you can go to speakers that are not connected to any other amp source. as long as you check the Ohms.

Amp->built-in amp speaker. ext speaker out ->other speakers(whether a single cabinet, multi cabinet, or speakers in another combo amp ( as long as the other combo amps is not connected to the speakers also.

Joe

My eldest raised eyebrows after I read one of Joe's posts and fed my 30W Marshall's headphone output into the input side of my 120W Phoenix.

To a certain extent, lots of things are possible; but you do have to be careful what you're feeding to where.

Best,

A :-)

I'll add the standard warning here...

Be careful about where you plug in your inputs and outputs, keep your instrument level signals separated from your speaker level signals.

Bad:
Extention speaker jack out -> Headphones. (popping, breaking)
Extention speaker jack out -> Computer sound card.(smoking, frying)
Extention speaker jack out -> Input of another amp.(smoking, frying)

Good:
Extention speaker jack out -> unamplified cab
Headphone out -> Computer sound card
Headphone out -> Input to ther amp
Headphone out -> Headphones

eek, no idea that doing those things could ruin an amp undercat, thanks for the warnings, the first thing I would probably have tried would have been to connect the extension speaker output to the input of my other amp.

I'm still kinda confused as to how I would go about connecting to another speaker. Heres what I'm trying to do. I have a Peavey Classic 30 which has an extension speaker output. I also have a Marshall MGDFX15 combo amp. Where exactly would I plug the output from the speaker extension on the PC30 into on the Marshall? Thanks.

I've got a Marshall MG15DFX too, and the only way you could use the internal speaker in that is to get a 1/4" jack socket, and wire one of those onto the back of the speaker. Wire a 1/4" jack plug onto the wires coming out of the bottom of the amp chassis, and then you could either have the output of the marshall into its own speaker, or the output from any other amp into the marshall's speaker. You'd need to take the back off to get to the speaker and wiring, and make sure the polarities are right, else bang. Dont turn any amp on without any form of load on the speaker outputs though! If I remember right, the marshall speaker is 8 ohms, so look for an 8 ohm ext socket on the peavey.

Doug

EDIT: It would actually make more sense to have the 1/4" socket on the amp chassis wires, and a cable with a 1/4" plug coming from the speakers, as that is the normal way of doing it.

*adding a little more to the educational aspect of the thread...*

Here's a little help understanding why exactly you wouldn't want to plug your extension speaker jack into an input:

When you play guitar, the strings vibrating create an infintesimal amount of power through the pickups which is then transmitted out the jack of the guitar, down the lead, and into the input of your amplifier. Your amplifier's job is to take that little teeny signal and boost it up to the point where it's powerful enough to drive the ocillations of a speaker.

What your guitar is actually putting out is a tiny amount of electricity, so little that putting a battery in the guitar to enhance that signal increases it's power significantly, and the battery lasts for months!

Contrast that with what your amplifier is putting to it's speaker(s): something between 15-300 watts RMS!

Now just imagine what it would do if you took your speaker output (your big wattage) and fed it to an input that was planning on handling only what a guitar would normally send. It attempts to magnify that signal by 100x, and you can see where the fireworks come from!

I got that, makes perfect sense, thanks alot.