Registered User
Join date: Sep 2007
472 IQ
Ok i have a cab of 8ohm n 120 watts
idk what to match it to though

i see cabs with 100w heads to 120w cabs
n even 15w to 100w cabs

why are they matched as such?
also do the ohm between cabs n head need to match for best sound?
Registered User
Join date: Feb 2010
198 IQ
All you have to worry about is matching ohms and making sure that the head isn't a higher wattage than the cabinet. You can put 15, 30, 45, 50, etc. on a 100w or higher cab as long as the ohms match.
FoxHound Elite
Join date: Jun 2008
1,182 IQ
Its my understanding that you can plug up to most cabinets that are rated at or above the impedance rating of your head.

For example, if you have a 4 ohm head, then it can generally handle a 4ohm cab or an 8ohm cab without to many problems.

However, you can damage your cab AND your head if you load down. If your head is rated at 8 ohms, its not a good idea to plug in a 2ohm or 4ohm cab.
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Registered User
Join date: Sep 2007
472 IQ
ok i understand, spent the last hour doing research..
though wont their be a volume different to having an 15w head matched to a 100w cab
versus high on both
666lb bongsession
Join date: Jun 2007
2,002 IQ
Ohms match between to the head and cab so either a) you don't blow your OT or b) so that it runs efficiently. Nothing to do with sound. ALWAYS ALWAYS ALWAYS match the ohms.

The cabs are usually rated at or more than the head. Remember though that a head's wattage rating is only the output at breakup (RMS), so amps actually put out more than they're rated at.

That said though the average person will never run it that loudly, so it's no real big deal.

In short: Always match ohms, and either match or exceed head wattage.

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