speakerohms mismatch question

edadmartin · Posted: Thu Nov 22, 2007 8:32 am Post subject: speakerohms mismatch question

Im rebuilding a kalamazooII and plan to make a new cab for it as well.I have a few rola 10" speakers and thought a 2 x 10 combo would be cool.so my question is will the stock transformers handle the ohms mismatch.Kalamazoos run at 8 ohms the 15 watt rolas came out of a hammond cab that had 9 speakers in it .the ohms is 5.5 per speaker.what do you think?? Laughing

tw001_tw · Puppy Joined: 26 Mar 2007 Posts: 204 Location: St. Louis

I'd say a pure judgment call on this one. If the OT is abnormally large
for the design, it might be safe to do it (run the speakers at 11 ohms)
instead of the 8. In this case it should be able to handle the extra load
for a long time to come - it may cut the life short, but should provide a
while of working just fine (I'm talking years(?)). It will also shorten the
life of the power tubes some too - how much, I don't know.
However, if the OT is say, rated at 22 watts and its in a 20 watt amp, I
wouldn't try it.By the book? what book? Razz

If you want to play it safe - don't do it.

(I play it safe with amps, if that matters Twisted Evil

)

nigelwright7557 · Posted: Mon May 19, 2008 9:04 am Post subject: Re: speakerohms mismatch question

Structo · Posted: Sat Jul 05, 2008 8:53 am Post subject:

You can generally mismatch by 100% on a tube amp.
IOW, you can use a 4 ohm tap on the amp to 8 ohm speaker.
But don't go from a 4 ohm tap to 16 ohm speaker.
Ideally, you should match from amp to speaker.