Coincident with 8 ohm vs16 ohm

I have the Super Eclipse 3's. My cj Premier 12's (140W's with a 4 ohm tap) won't drive them- I don't think these amps really ever 'turn on' into a place where they are supposed to work. I bought a 30w cj Premier 11xs with a 8 ohm tap and it absolutley lights up the Coincident speakers. I had a similiar result with a 30w solid state amp- it worked great. I think a 8 ohm output impendece will be fine based on my experiance.

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.

I thank you all for your useful oponions,in theory if your amp
output empedance cover the exact or very near empedance scala of speakers this is the best amp-speaker synergy.
Some nominal 8 ohm speakers dip to 3 ohms in bass region (ie JM Lab)and if you connect your amp 8 ohm tap you loose some degree bass control and detail, and some nominal 8 ohm speakers dip to 4 ohm in high frequency region)(ie: Verity Sarastro)and again if you use 8 ohm tap of your amp you loose some opennes or airy highs if your amp has not enough power to overcome this caveat, that is why low or mid powered tube amps need flat empedance speakers for the best result, I do not know how empedance swing is there for Coincident speakers? and for the 4-8-16 ohm taps of tubed amps, less wire means better s/n ratio and clearer sond better soundstage in general so as long as your speakers empedance scala permit one should always prefer to use 16 ohm to 8 ohm,8 ohm to 4 ohm, as far as I know.

Kalan, I agree with your post regarding impedence:

"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."

I think my problem with using the P12's with the Super Eclipse 3's was due to the efficiency of the speakers. The P12's just didn't like to run with only a few watts of power output. My P12's drove my B&W N803N's with no problem and sounded great but I think they were within their desired operating power output while driving those speakers. With the very efficient Eclipse 3's, the P12's were idling and not sounding their best. I can push the cj 11xs and it's like a spotlight from heaven compared to the P12's.

Please don't take this the wrong way, but I never understand these threads. It's fine to ask for insight to share experience, but there is no way I'd use the input you get from people to determine which output tap to use.

In my mind, no matter who you are getting advice from, your mileage will vary. Their system (amplifier, loudspeaker cable, and loudspeaker) and tastes are going to differ from yours in some way. You simply MUST experiment on your own. For just about every speaker, its published impedance value is of little importance in relation to its impedance and phase angle curves, and even less importance in relation to how your particular amplifier is able to drive that load, using your speaker cables.

My solution is to try both, and evaluate each over a period of a day or two. Play a variety of music, and see which works better for YOU.

Good luck!!!