hey guys, i want to add an external speaker to my peavey express 112 but it doesn't have a speaker output though it does have a headphone output... can i just simply use the headphone output to connect to the external speakers or do i have to add one myself???

If there is no external speaker jack there usually is a reason.

Is the combo's speaker a 4 Ohm speaker? If the speaker is 4 Ohm then adding an external speaker probably is not something you can do as most of the Peavey solid state amps have a 4 Ohm minimum load. (A few will do 2 Ohms, but pretty sure this little combo is 4 Ohm minimum.) Been looking for specs or a manual but no luck yet.

If the combo speaker is 4 Ohm then connecting another cab would cause the amp to overload and overheat. You can plug a speaker cab into the headphone jack without hurting the amp but you won't hear it very well at all since that is like 100 milliwatts tops.

If the combo's built-in speaker is 4 Ohm, you could swap it for an 8 Ohm speaker. Then you could add another 8 ohm cab and it would be about the same volume with both speakers engaged as it is now, but would be about half as loud with only the built-in speaker. I really don't think there is a lot to gain here.

It might make more sense to get a bigger amp if you need more volume. Or run a slave amp from the headphone output. Like I said I can't find much online about this discontinued amp so I can't say for sure. However the speaker should be labeled with the impedance.

If it is 8 Ohm then you could add a speaker out jack yourself.

http://www.manualslib.com/manual/306126/Peavey-Express-112.html#manual

here is the manual... i'm looking it up but i'm not finding anything

EDIT: i think it's 65w into 8 ohm