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4 ohm taps on an 8 ohm speaker

I'm using a Cary V12r (with 6550 output tubes) to drive a pair of Verity Fidelio Encores. I've always used the 8 ohm taps on the amp. Recently, on a whim, I tried the 4 ohm tap and enjoyed a significant improvement in sound quality. The amp is quieter, with reduced background noise, and the bass tightened up and became more defined. So two questions: 1) I don't think I'm hurting the amp by running it this way, but I'd be curious to hear if anyone has an opinion on that, and 2) Any thoughts on why the 4 ohm taps would sound better on an 8 ohm speaker? Regards.
grimace

Showing 2 responses by jmcgrogan2

jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
I've also noticed the same thing on my VAC PA 35/35 amp. My speakers are a nominal 8 ohm load, but they sound so much better attached to the 4 ohm taps. Kevin Hayes of VAC has always been very encouraging of experimenting with the different taps. He says that many times the amp will sound best when set to the speakers minimum impedance, and not their nominal impedance. He doesn't seem to have any concern as to how this may damage the amp or speakers. I am glad that I experimented, because the improvement in sound is certainly a nice payoff.

I have been told that the lower ohm taps will drive more current, whereas the higher ohm taps will drive more voltage. I don't know if there is any truth to that though. Maybe our local electrical hero Al (Almarg) will drop in and enlighten us on this phenomenon.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Thanks a lot for the explanation Al, you ARE the man!!!
I think you nailed it with the first line in your last paragraph: "The bottom line: It pays to experiment with the different taps, and no harm will result regardless of which tap is selected."

Cheers,
John
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