load/ohm question from guitar guy

[Lex]

Jon/others, a guitar guy asked me a question, I guess because I seemed pretty knowledgable about loads and impedence. But I still want to make sure I am thinking right on this...

Here was his question:

My JMP Marshall (2204 50 watt)
The Canadian Version with 16 ohm tap
so it only has 4-8 impedance on the selector switch (back of amp)
My dilemma is I have a 4x12 with G12-T-75 Speakers,I believe they are 16 ohm...
Is it safe to play this Amp on this cab???

I figure since the amp is rated at a 4 or 8 ohm load, he's find driving a 16 ohm load cabinet as the demans won't be that much. I figure it was rated at 16 ohms so a double stack would create an 8 ohm load. Does this sound right?

I think he should set his amp to 8 ohms for the 16 ohm load, and be careful, he could still melt voice coils with that much juice. Am I right here guys?

Thanks.
doug

[JonMarsh]

Yeah, set for 8 ohms, don't worry about the cab, the G12-T-75 aren't the best sounding Celestions in Marshal Cabs (prefer Vinatage 30's or Celestion Greenbacks myself, but they're 75W each and 300 for the cab, so no worry about the speakers.

You don't want too much of an impedance mismatch on the amp to cab, though, because it stresses the tubes, even if it's too light a load.

[Lex]

cool, thanks Jon!