speaker impeadance question

"I’m afraid I must offer another correction, this being a matter of considerable significance... It was actually a different character, "Emily Litella," who concluded her commentary on Saturday Night Live with the words "never mind." " 

Well, it just goes to show you. It’s always something.

:-)

Best,
-- Al

(For others who may not be aware, Duke's statement just above was made famous by "Roseanne Rosannadanna")

Ok thanks for all the great replies. However now that we have cleared up that I’m using SS amps. Has the consensus  changed any? Will I cause any damage to either the speaker or the amp by using them on the 8 ohm taps? I think this is my main question/concern.

Thanks

No, you won’t hurt anything by using the 8 ohm taps.

In some other situations, involving amps that are much less powerful and/or speakers that are much less sensitive, the reduction in the maximum power capability of the amp that would presumably result from using a tap that does not correspond to the impedance of the speaker at most frequencies (especially in the bass and mid-bass regions, where lots of energy is typically required) might be conducive to driving the amp into clipping. Which in turn can be harmful to tweeters.

However, given the "conservatively rated" 600 watt capability of your amp (when load impedance corresponds to the designation of the tap that is used), and given the 88.3 db/2.83 volt/1 meter measured sensitivity of your speakers, and given the "Power Guard" function provided by your amp (which reduces its gain if and when necessary to keep the difference between output and input from exceeding 0.3%), that risk would appear to have zero chance of arising in your particular situation.

Regards,
-- Al

Hi Al, 

I've been checking in from time to time.  Actually, I've been waiting for you to post something because I always learn something from your responses.

The OP's post caught my interest because he tapped [pun intended] into a topic that you, Ralph and I posted about several years ago.  Perhaps you could expound on why the OP's solid state amp would be using autoformers at all.  In the usual case, solid state amps have very low output impedances.  Hence, their damping factor should be high. 

I think Ralph may have posted several years ago that a DF of over 8 or maybe 10 isn't all that important. In the OP's case, I am surprised that his DF isn't higher since his amp is solid state.  Is there some design feature relating to the output transistors that makes the use of autoformers necessary?    

Further, in the OP's case, you posted that his amp is rated at 600 watts and his speakers have a reasonable 88 db sensitivity.  So what is the issue?  Just curious about the use of autoformers in this application and why the OP perceives that there is a sonic difference between the 4 ohm and 8 ohm taps.  I am a little surprised. 

BIF