Correct OHMs

loanzac · #1 03-17-2010, 09:06 AM

Got a silly question. I bought a SWR Goliath 3 cab, and am unsure if it is 8OHM or 4OHM, their are no markings on the back of it indicating which version it is. I want to pair it with a thunderfunk 420 is this a good idea? meaning will the OHM rating be compatible and no blow-up of either head or speaker?

Jaco who? · #2 03-17-2010, 09:15 AM

You'll be fine either way as long as you run the one cab by itself, it just won't be as loud if it's 8Ωs. You could remove one of the speakers and see whats printed on the back. If they're 4 or 16Ω, chances are it's a 4Ω cab. If they're 8Ω, chances are it's an 8Ω cab.

http://colomar.com/Shavano/4x12wiring.html

This shows the common wiring for 4 speaker cabs.

Bassamatic · #3 03-17-2010, 09:18 AM

You have to get someone to measure it. Note - it will not be exactly 4 or 8, but around there.

What is the impedance of your Thunderfunk cab?

You need to be sure that the combined impedance is not less than your head is rated for.

ie: 4 & 4 = 2 Ohms 4 & 8 = 3 Ohms 8 & 8 = 4 Ohms

If the cabs are different impedance, then note that the cab with the lowest impedance will get 2 x the power of the other one and must be able to handle it.