Scott, no damage will result. Most amps will output a bit more power with the matched load, though this is not always the case. The lower impedance tap will have the greater damping factor, which will result in better bass control. Will you prefer the sound? Who knows? Try both and see which you prefer. The other thing to consider is that most eight ohm rated speakers that are not designed with a conjugal load are rarely eight ohms across the full bandwith and frequently dip to below four ohms.
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.
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.
Alraul is correct - the full primary winding is always seen
by the output tubes.
The different taps are on the secondary side of the the
transformer with higher tap impedance having more windings.
Hence the 4 ohm tap will have the fewest windings of the
set of 4, 8, and 16 ohm taps.
Dr. Gregory Greenman
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!
Thanks, I just wanted to make sure there were no issues before I started running them like that for an extended period of time. I tried the 4ohm tap and I felt I liked it beeter that way.
Thanks again. Scott
Well, I can definatly notice a difference. I just got these speakers about a week and a half ago. When I first hooked them up I forgot to change from 4 to 6 ohm because my Thiels are 4 ohm. I liked the speakers right away.
After I noticed that I forgot to change to the 8 ohm tap, I quickly changed the amps to the 8 ohm tap.
After a few LP's I began to not hear the bass. So after you all confirmed that I would not damage anything, I switched back to the 4 ohm tao. The bass is back.
You need all the help you can get with the Shearwaters. They are not bass heavey at all.
"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!"
You just pinpointed why I ended my post (giving advice) with my qualifications. I notice Morbius subscribes to this concept, too!
I do end my post with my qualifications - and I get a lot
of flak for doing so.
The qualifications work as a double-edged sword.
The fact that I put "Physicist" after my name says that I
do have a special expertise in Physics. It also says that
I have absolutely no special qualifications in anything else.
Dr. Gregory Greenman
Morbius, I think you will find this amusing
I have spoke to a good work friend who is an electrical engineer. He has been in this profession for over 25 years.
I was telling him about the discussion on the CABLE forum of breaking in power cords. I almost had to call a code red to get him medical attention, because he couldn't stop laughing so hard.
How anal is this crap?
Would like to add that this has been a useful thread for me. I am running a pair of Granite Audio 860.1 tubed monoblocks into Equation 25 speakers and had been using the 8 ohm tap- never gave it much thought. The speakers are 6 ohm. Tried the 4 ohm last night and was very pleasantly surprised- cleaner, more articulate bass, and warmer midrange, without losing too much on top- just the effect I have been looking for with mixed success by trying different cabling.
Are there any technical reasons that a 6 ohm speaker should be driven better with a 4 ohm than a 8 ohm amp?
Makes me wonder about the Proacs that I sold because I was unhappy with them. Wonder how they would have sounded with the 4 ohm tap.
Of course the output tubes are always connected to the full primary winding of the transformer. So everyone is talking about the secondary windings, 4 vs 8 ohms. However, when you put an 8ohm load on the 4 ohm tap (or 4 on 8) you have changed the impedance loading on the output tubes, even though you never moved their wires. This probably affects the operating characteristics of the tubes.