CM10's and Mcintosh MA8000

[Jagman]

After weeks of listening, including full weeks at both taps, with detailed notes I have come to some conclusions.

My week of listening and note taking started with 8 Ohm connections. The sound has plenty of energy, sizzle, slam if not a too lean sound on some recordings. Bass lights seem a tad tighter, but not as full. Cymbals have more sheen but almost too feathery. Kick drum has more punch but again sounds thinner. Lastly vocals are crystal clear but sound almost as if the singer is singing a half octave above natural. The music can be driven at the same volume level with almost exactly 4% less vs 4 Ohm, I.e., 36% vs 40% on the preamp. The best way I can sum it up is that the sound seems more charged and crisp, but also a bit dry and sterile on most recordings. Most important, as much as I tried to resist, the music would become more fatiguing and less musical. It just wasn't as sweet and natural sounding.

A week of 4 Ohm listening with notes started out in a now predictable manner. I had to pump up the volume approximately 4% to get same sound level. Music was quite a bit fuller, richer, smoother with a tad less tight bass, but overall more of it. That's not to say bass was ever bloated, just had a hair less punch. Again I'll say vocals, piano, percussion, etc., sounded to me like how the artist and producer likely intended it to sound. I never felt any listener fatigue what so ever. The music was lush, smooth, and rich.

The areas that would cause me to question or wonder what a piece of music would sound like on either of the connections were typically dependent upon type of music, and that is where a bit of consternation would occur ever so slightly. For example, on acoustic recordings like Uncle Tupelos classic "March 16-20 1992", there is really no question that 4 Ohm taps sound much better, with an emphasis on the much. One Steely Dan's "Two against nature", with electric bass, guitars, keyboards and miked saxophone, the 8 Ohm tap delivers a more energetic sound with more punch and sizzle. That's not to say 4 Ohms sounded bad by any means. What it typically requires in a good 4 to 5% bump in volume. At that level you get almost all the slam and punch with the fuller sound.

I believe there have been two things at play with this analysis. One is the perception of more power on tap at 8 Ohms and the feeling that I was giving some of that up with 4 Ohms. I needed to accept there was need for more volume gain with 4 Ohms and not fret over that.

The second is the issue of Mcintosh itself, autoformers and/or the need for more powerful amps with Mcintosh amps than other brands. I doubt if the MA8000 was 500wpc vs 300wpc I would have ever felt the need to experiment to this level due to a less likely high degree of difference. As it stands at 300wpc, the 8000 may be on the cusp of power, where the difference is more noticeable than ideal. I can only suggest that the use of Autoformers vs the amp producing greater levels as required along the frequencies plot line may complicate things a bit vs being an asset in totality. All in all I do love the Mcintosh sound and at 4 Ohms, it sounds like what I've heard in a Mcintosh amplifier much more so than at 8Ohms. I just wish at times it operated liked my old Classe CA301 where there was no opportunity to select a particular tap, but the amp would double its power rating etc., since I don't ever recall having this issue before. Just a thought.
For now I'm content again listening to the 4 Ohm taps and fully appreciate the more natural, smooth and silky sound it delivers.