Would it be ok to run a 4 ohm head into an 8 ohm cab that has two woofers and a horn inside?
If the head is solid state, yes. If it's tube, no. I'm going to assume yes for you.
Well I'm actually doing this for my bassist. His head-area in his fender bassman250 died.but he wants to use the cab portion.... The head he's looking at is SS, are you positive it'll work? We've got a gig tomorrow night :p
Yeah, A SS head can always handle a cab with a higher impedance, it just own't put out as much juice. What is the hear rated at for rms wattage for 8 ohms, and what is the cab rated at for the same?
I'm going to assume yes for you.
IT should work, but the best way for us to or Google to help you is tell us what head he is using if he or you knows. Nearly all SS heads can handle a load higher than the rating. So say the head takes 4 ohms and puts out 200 watts, it'll take an 8 but maybe put out 130 watts, 16 ohm 60 watts etc, give it a two ohm load and you'll kill it though.
Moral: only higher ohm resistance + only SS lower = ok but wattage will be lower
As long as the cabinet's ohms rating is not less than that of the amplifier head's ohms rating, you're fine. If the cabinet's rating is less than that of the amplifier, then you're making the amp work to hard and it will probably fry.