Can my MC275 power speakers with 91db sensitivity

Al, I have a quick question about "kickback inductance." On rare occasion, I switch back and forth the hot speaker wire between the 4 and 8 ohm outputs taps. The time interval of a "no-load" condition is less than a second. When doing the switch, I mute my linestage to ensure a signal is not being sent to the amp. Could a short interval open circuit of that magnitude damage my amp?

The reason I don't turn the amp off before switching the taps around is because I am reluctant to subject the amp to frequent off and on recycling.

Hi Bruce,

I can't envision any way in which that might cause a problem. Inductive kickback occurs because the voltage across an inductance (in this case, inductance in the transformer) is proportional to the amount of inductance multiplied by the rate of change of current. A very abrupt change in the amount of current flowing through an inductance can result in a VERY large voltage spike, albeit a brief one, if the energy has nowhere to go. If that spike occurs in the transformer secondary, it can result in an even larger spike in the primary, due to multiplication by the turns ratio of the two windings. But without a signal being present, none of that would happen.

The one exception I can think of to that (which doesn't apply to your situation) might be if the amp were turned on or turned off without a load being present. In that situation an internally generated turn-on or turn-off transient might conceivably be large enough and fast enough to constitute a potentially damaging (or long-term reliability degrading) "signal." But even that would seem to be unlikely in most (but not all) cases. One situation I can envision in which it MIGHT be a problem is if the amp has a B+ relay which abruptly turns on plate voltages to the output tubes some seconds after turn-on. That would result in an abrupt change in the amount of DC current flowing in the transformer primary.

Best regards,
-- Al

Dear Al and company,

First, let me thank al of you for sharing your time, knowledge and insight with me. Now, let me explain how I arrived at this question. I was at a stereo store not even looking for speakers, and I heard the new Sonus Faber Olympica's and I was blown away. The best description I can give is "very warm." I felt like I was swimming in the music...I wanted to grab the first (decent looking) woman I saw and dance with her. I then listened to three other sets of speakers just to make sure it wasn't the effect of their listening room, and the others speakers did not come close to the SF Olympica's. I can't really afford the Olympica's right now, so I was hoping the Cremona M's would be close to the Olympica's.

Now, if I could say a few words about my listening. I love music, and listening to music is one of my favorite activities. However, I am not as concerned with the technical aspects of music reproduction as some are. What I mean is that I recognize that many people are fascinated by the never-ending technical pursuit of brilliant engineers who endeavor to design and created better equipment. And I have witnessed golden-eared experts listen to equipment, and they sometimes listen to music, critically, in a way that seems to prevent them from enjoying the music. Missing the for the forest for the trees. While that is important, I just want to hear the music, and I want it to sound good. For example, there used to be these "magic-eye" poster that initially looked like a bunch of dots, but if you relaxed a certain muscle in your eyes, an image would appear. I just want equipment good enough to allow the image to appear, in other words, for me to melt away into the music.
All this being said, I do believe good equipment makes a big difference in enjoyment. For example, when I upgraded to a clearaudio performance turntable, it was like switching from normal TV to HD. Everything sounded a lot better. And I remember when I went form my old Klipsch Heresy's to the Genesis G7's (which I no longer have), certain songs sounded completely different (and better). I.e. Copland's fanfare for the common man became so music more dramatic and powerful (and I actually liked it now). So I am far from a ludite regarding equipment. My only point is that the finer intricacies like phase angle drop off, etc.;-- the more technical aspects of a amp's or speaker's performance--might be very recognizable to guru's like Almarg, but might not be noticed by me.

Perhaps this will modify your speaker recommendations. Thanks again for everyone's help.

So it is Cremona M that you are considering. Much easier to drive than the original Cremona, which is what Al originally discussed.

Here is a thread with a guy who successfully used MC275 with Cremona M.

Cremona M with MC275

Thanks Al, I guess I won't be doing that anymore ! Elegal, regarding your last post, your description of what you are looking for is very well said, and coincidentally mirrors my own. I have only heard SF speakers in the stores (never at home), and they always sounded great. But also I would highly recommend you check out Harbeth SHL5 with your amplifier, as well, before you pull the trigger. Highly engaging, musically. Best of luck.