ohms question.

[dugg365]

I have an amp that has been converted to a head. It has a speaker out that is currently
the main output, a tap off of that jack was for the speaker in the combo cabinet which no longer exists. The jack is looking for 8 ohms. This leads me to believe it had an 8 ohm speaker and an 8 ohm extension jack. If i'm running a 2x10 speaker cab it should be 16 ohms??

[JPHeisz]

It's likely that by plugging in the ext speaker, it switched off the int one. So, if the one that was inside the cab originally was 8 ohms, you should try to match this. Two 4 ohm speakers in series makes 8 ohms.
If in doubt, go higher with the impedance (for example: 16 ohms (two 8's in series) as opposed to 4 ohms (two 8's in parallel). Lower impedance draws more current from the amp and this can stress it.

[Enzo]

WHAT did the amp used to be before it became a head?