4 ohm tap vs 8 ohm tap

At the 4 ohm tap, you would be running the signal through more transformer windings than at the 8 or 16 ohm tap. The 2 ohm tap (if you have one) would go thru even more output transformer windings. And all things being equal (and they never are) more wire yields a more degraded signal. How much? depends on if the better damping factor is worth the (small) loss in signal quality.

Also the amp may sound different into the different impedance taps. IT may not "sound right" using a 2 or 4 ohm tap with you speakers. things may sound better with the 8. Or with the four. use your ears. depends on what low impedance dips your speakers have.

Aroc,

You have received incorrect info. No matter which tap you use, the full primary of the output transformer is used, and on the secondary, the HIGHER the tap impedance, the MORE of the winding is used (for example, on an winding with 4, 8 & 16 ohm taps, the 4 ohm tap is the CENTER TAP).

Another thing--according to the Dynaco ST-70 manual, running an 8 ohm speaker on a four ohm tap reduces power, but "the operating conditions are shifted from maximum power output to minimum distortion."

And, yes, the damping factor will be higher from the lower tap. The great thing is that it costs nothing to find out which way sounds better, and will not damage your amp (if you turn off the amp before playing with the wiring). Luceeeee, you got some listening to do!

BTW, I am the designer of a tube power amp, and have been an electronic technician for over 30 years.

Hi Al. I would suggest listening to Al. He and I discussed this very same topic quiet some time ago. My speakers, Roman Audio Centurions are an 8-ohm rated speaker and I am running them on the 4 ohm taps on my tube amp. At first I didn't think there there would be a difference, but Al was right, there is. Try it and see for youself.

SHAMELESS PLUG: Al does make a really awesome tube amp, I use one.

Thanks for the corrections Al. I did a quick internet search and you are right on the money. Thanks again. Gotta watch who you get advise from!