Question on running various ohm loads on a Heartbreaker head

[cworley5150]

Would it be a problem to run one 8ohm cab and one 16ohm cab at the same time on my Heartbreaker head? The Heartbreaker has one 16ohm speaker jack, two 8ohms and two 4ohms. Of course I would plug the 16ohm cab into the single 16ohm jack and the 8 ohm cab into one of the 8ohm jacks. Will that hurt the output transformer in any way? Would that be a total 12ohm load?

Thanks,
Chris

 

[cyber104]

That's a 5.33 ohm load. The only possibility that I would do would be to link the 2 cabinets together and plug into your 4 ohm jack. I still wouldn't be comfortable doing it for too long but in theory you should be safe

 

[94Tremoverb]

Either - plug the 16-ohm cab into a 8-ohm jack and the 8-ohm cab into a 4-ohm jack. This will give equal power to both cabs. Mesa call this a 'safe mismatch', but really it's more a combined mismatch giving an overall match.

Or - plug both into either the 8-ohm or the 4-ohm jacks. This will give a 5.33-ohm total load. It's absolutely safe either way. Mesa amps are even less fussy about impedance matching than most amps - it's a myth that your amp will explode if you mismatch . Almost any decent tube amp will handle a 2:1 mismatch in either direction, and all Mesas certainly will. It will also give a power ratio of 1/3 to the 16-ohm cab and 2/3 to the 8-ohm cab, so this may be worth taking into account if the 8-ohm cab is low-rated, or the 16-ohm cab is not very sensitive. The two settings will sound different, so it's worth trying both. If you can't decide, I would go with both 4-ohm jack since it's slightly less hard on the tubes.

But *don't* plug the 16-ohm cab into the 16-ohm jack and the 8-ohm cab into a 8-ohm jack - that's actually a low mismatch because both taps are fully loaded, and might actually strain the tubes a bit.

 

[jpdennis]

Thanks 94Tremoverb. This concept has been confusing me as well.

Dennis

 

[tremoverb nick]

So how does it work with a tremoverb combo an a 2x12 recto cab?

 

[cworley5150]

Thanks for the responses. I had read in the owners manual that Mesa's aren't very sensitive to mismatching the ohms and they actually encourage trying it for different tones. I just wanted to hear from users that had tried it. Thanks again.