3/4 Stack Cab/Head Impedance Matching Questions

BigDreamer

BigDreamer

New member
So I'm looking into treating myself to a 4x12 to add to my tremoverb 1/4 stack, but no matter how hard I try to understand the information out there about this impedance stuff, I just feel stupid.

So the tremoverb has one 16ohm input, two 8ohm inputs, and two 4ohm inputs. Currently I'm using a 2x12 mesa cab where I hook the speaker cable from its 8ohm jack to one of the head's 8ohm jacks.

My questions are:

* What total ohm rating am I looking for on the 4x12?

* What inputs will I be using on the head/cabs?

* Are the 8ohm "stereo" jacks on marshall 1960a cabs used for two cabs specifically (like i'm trying to do), or are those used for using two heads each with 2 of the 4 speakers?

Hopefully my cab options aren't too limited! Thanks guys!
 
Re: 3/4 Stack Cab/Head Impedance Matching Questions

Relax, there's nothing complicated about it, especially with an amp like yours. Mesa's made it almost idiot proof.

The 16 ohm jack is for one 16 ohm cab. That's easy.

The two 8 ohm jacks are expecting a total load of 8 ohms in parallel. This means they can handle either a single 8 ohm cab or two 16 ohm cabs. Two 16 ohm cabs in parallel give you a total of 8 ohms.

The two 4 ohm jacks are expecting a total load of 4 ohms in parallel. Same as above, except one 4 ohm cab or two 8 ohm cabs.

You're either going to end up with an 8 ohm or 16 ohm cab. If it's an 8 ohm cab, plug both your cabs into the 4 ohm jacks. If it's a 16 ohm cab, plug that into the 16 ohm jack and your 2x12 into an 8 ohm jack.

Marshall 4x12's are usually 16 ohm. Mesa 4x12's are usually 8 ohm. I think you'll be happier with a Mesa cab personally, but it's your call.
 
Re: 3/4 Stack Cab/Head Impedance Matching Questions

And ya, I was also thinking going the Mesa route, but I did just find a Krank Krankenstein cab locally going for $500...

Anybody have a preference between Mesa and Krank cabs?
 
Re: 3/4 Stack Cab/Head Impedance Matching Questions

Glad I could help.

Another thing to know is that Mesa amps are generally very tolerant of impedance mismatches, so long as it's not too big of a mismatch (don't plug a 4 ohm cab into the 16 ohm jack, for example). You can get away with a 4 ohm load in the 8 ohm jacks, or an 8 ohm load in the 4 ohm jacks. You will probably burn through your power tubes faster if you do this, but it won't break the output transformer or anything bad like that.

I doubt you'll need or want to do an impedance mismatch though.
 
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