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Can I hook up speakers without using the ground?

I accidentally hooked up some speakers using the 4 0hm tap for the positive run but accidentally connected the return to the 4 ohm tap instead of the common/ground.

I didn't damage anything but I didn't leave it connected that way long. It had some interesting sonic effects that I did not take the time to explore out of caution. The hook up reminds me somewhat of the hook up you used with the old David Hafler design for pseudo quad set ups rear speakers.

The amp is a Mesa Barron dual mono. Speakers are 3 way dynamics with very expensive tweeters ergo my caution.

Is there any short range or long range risk doing this?
newbee
newbee OP
4,767 posts
 
I misspoke - I hooked the return run up to the 8 ohm tap. Sorry about that. :-)
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almarg's avatar
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almarg
9,670 posts
 
Hi Newbee,

I don't think you would have done any damage during the brief time you had it connected that way, especially if the volume wasn't particularly loud. But it's not a good idea, and could conceivably result in damage to the amplifier in the long term, as I see it.

Basically what you are doing is connecting the speaker across fewer turns of the transformer secondary than it should be connected across. That amounts to "light loading" the amplifier, which if carried to an extreme would approach the kind of effect that running a tube amp with no load can have, namely damage to the transformer and/or output tubes resulting from inductive kickback.

According to my calculations what you probably did was to light load the amplifier by a factor of about 5.8, corresponding to what would happen if you were to connect a hypothetical 23 ohm speaker between the 4 ohm tap and ground. As I say, it's very doubtful that would hurt anything in the short term, but it is not a good idea.

Best regards,
-- Al
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