Coincident with 8 ohm vs16 ohm

I have the Super Eclipse III's and can switch my amps between 4 and 8 ohms. The speakers sound better when driven by the amps in their 4-Ohm setting.

Even though the Coincident spec's say the speakers are nominally 14-Ohm speakers--which is probably true, they will actually dip much lower with program material being played.

I love the Supers (I had the original version and upgraded to the III's), but to me they "seem" much closer to an 8-Ohm speaker than any thing else. They will just lap up huge amounts of SS power with bass and dynamics that surprised me. This is usually not the characteristics of a high-impedance speaker.

If you can try between various settings, try them all, and see what you get.

With a tube power amp, supposedly the only difference between the 4-Ohm tap vs. the 8-Ohm tap is that the 4-Ohm tap has more active secondary windings in the output transformer. Someone with more technical knowledge could maybe clarify this.

I don't doubt anybody's experiential findings, but to really get to the bottom of whether amp A does better in 4-Ohm mode or 8-Ohm mode, the SAME amp should be used for tests in both 4- and 8-Ohm modes. Amp A in 4-Ohm might fall on its nose compared to amp B in 8-Ohm mode, but too many other factors are involved to determine whether output impedance is at the root of the perceived differences.

Most solid state amps do not have output transformers (exceptions are many of the MacIntosh amps with their "autoformers") and have very low output impedances anyway. So, impedance output is basically a moot issue in most SS amps.

I would guess that some other factor is going on with the cj Premier 12's vs. the cj 11xs. In theory, all that's going on with lower impedance taps is more transformer windings in play. This usually translates to better control of difficult impedance load speakers, but perhaps a loss of transparency (maybe some additional phase shift--which may or may not be audible). With higher impedance load speakers, a lower impedance amp tap should not really affect its ability to “drive” the speaker per se.

I could be completely off on this. Maybe someone with more technical knowledge and experience in the area of transformers and impedance matching could maybe explain some of this stuff better.

In my system, the Super Eclipse III’s do better on lower output impedance settings at the amp and sound better with more power than with less. They simply eat up either larger tube- or SS watts with gusto. Their bass extension and control with the 510 watt Musical Fidelity kW-500 amp, for example, completely revamped my impressions of the Supers’ power and operating preferences.

The Coincident Super Eclipses III will dip into the 6-Ohm region between 3k Hz up to about 5k Hz. Whether this dip in that frequency range is significant to most tube amplifiers, I do not know. The Supers may not be as efficient many of us think. My experience with the Supers and larger amps corroborate some apparent lack of efficiency somewhere. I believe that lower frequency impedance dips *may* be more influential on amplifier demand, but I am not certain about that.

Since I have amps that can be switched between 4- and 8-Ohm output impedance, they do seem to have better “control” on the lower setting. This probably means that the speaker dips below 8 Ohms. No positive effect would occur to take advantage of the lower output setting if the speaker did not dip into the below-8-Ohms region. Other tube amps (not just mine) with adjustable outputs yield the same results with the Super Eclipses as well.

When it comes to solid state, the larger the amp, the better the Supers seem to perform in terms of sheer control, dynamic envelope, and bass extension. The whole discussion about over all musical appeal with smaller, often times more refined amps vs. larger, brute force amps, is a whole other debate. I am addressing solely “drive-ability” here.

I would expect some possible sense of "mere idling" on a truly high impedance speaker paired up with solid state amplification, but not with tube amps. SS will (normally) only put out the required current to drive a given impedance load (not talking about SS with output autoformers, here), if the SS amp has the power reserves to deliver the current to begin with, that is. A truly high impedance speaker will possibly not "draw" enough current from a SS amp for the correct target tonal balance or dynamic punch to occur. But tube amps do not work this way. Standard tube power amps pretty much put out the same voltage no matter the impedance of the speaker load, or actually sometimes have *lower* output into lower impedance loads.

My experience with the Super Eclipses (owned the Mk I’s and currently own the Mk III’s) with both tube and SS amps definitely favors more power on the drive-ability score. I am puzzled as to why a higher-powered TUBE amp operating with 4-Ohm taps could not drive the Supers as well as a lower-powered tube amp with 8-Ohm taps. There must be other factors going on.

I believe I have the theories (or principles) correct, but I am open any new information that would shed light on what might be going on here.

Since a few of us have the same model of speakers as the originator of the thread, it does seem odd that we experience such different results. Bottom line…as I---and a couple of others---mention earlier, try different amps with different output settings (when ever possible) with your speakers and let your ears be the judge.

Ben, Room dimensions and music material also play a big role in amp power demands with a given speaker. "Power music" (full orchestra, organ, and bass-heavy pop) played in a larger room will take quite a bit more power than chamber music, intimate jazz, small scale pop, etc. in a smaller room.

If you have hit upon the Cayin 265ai as a good match with the TE's in your room and music, that's great. Not all watts are created equal, for sure. For me personally, I wouldn't even consider driving my Coincident Super E III's with 2x40 SS watts. (The Supers are supposedly less easy to drive than the TE’s.)

In my system with my music, the ~220 watts of the GamuT M200's represent the lower limit of the power requirement I would attempt with solid state. About ninety-five, push/pull, triode watts is the lower limit I would try with tubes. This is just an approach based on my experience: room, music, dynamic preferences, etc. Yours obviously differs.