Tube Power Amp Reviews

Sure enough, I was peaking out at about 100W, even with the 92dB-sensitive Triangle Antals.

Now, it could be that I was getting such clean, clear sound from the MC2102 that I was tempted to push the volume a bit. I don't know. But I do know what the meters told me: I "needed" 100W.

Gosh, did I have enough power?

I hinted to Larry Fish that I'd heard a subjectively more powerful sound with the MC2000. The MC2102 has a smaller power supply, and its output tubes are run at lower voltages. The MC2000's plate-supply voltage was 500V, the MC2102's is 450V. Hence, 100Wpc instead of 135Wpc.

But if the sound was less powerful with the smaller amp, it was also slightly more soft and sweet.

"We're not running the tubes as hard," Larry observed. "It could be that the output tubes are operating more within their linear capabilities."

Ever heard KT88 or 6550 tubes sound hard, glassy, and glary? I sure have, but that's not how they sounded in the MC2101—or in the MC2000. Or in the MC275 reissue, for that matter.

Any other reason the two amps might sound different?

"Well, the MC2000 was a hybrid," Larry offered. "The MC2102 is an all-tube design. There are no transistors in the signal path."

"Oh? So you slipped in some transistors while Sidney wasn't looking?"

Larry was unflappable. "In the MC2000, there was an emitter follower between the driver tubes and the output stage. It consisted of four transistors per channel—two on the positive side, two on the negative. We could swing further with a given voltage that way. We wanted to increase the amount of drive to the output stage. That's how we got the MC2000 to 130W."

Could I be hearing the absence of transistors in the MC2102's signal path?

Nah...more likely it was a matter of less power. (I don't think Sidney Corderman set out to design different-sounding amplifiers. But he couldn't include such a massive power supply in a $6000 amp.)

The MC2102's lower power meant a loss of dynamics and dynamic headroom (subjectively, anyway). But it also might be what produced that gentler, more softly lit sound I found so beguiling. In any event, lower power was dictated by the MC2102's much lower price point: Not as much money for a massive power supply.

Some listeners might prefer the MC2000, and maybe I'm making too much of the sonic differences I heard—reviewers tend to do that. At any rate, you can't buy the MC2000 new, and even when you could, it sold for 15 fat ones. At $6k, the MC2102 is a bargain by comparison.

So maybe you should consider buying two.

There's a three-position slide switch on the chassis next to the input connectors. The three positions are Stereo, Parallel Mono, and Bridged Mono. The MC2102 can be bridged to provide 200W mono into 16, 8, or 4 ohms, or the two channels can be run parallel to provide 200W into 4, 2, or 1 ohm.

"When you run mono bridged," Larry explained, "you insert a phase inverter in the input of one of the channels, so one channel is 180 degrees out of phase. The speaker is connected between the two hot output terminals. The plus and minus leads from the speaker both go to separate positive terminals.

"Now you have a fully balanced 200W amplifier into 16, 8, or 4 ohms. You have two output transformers, physically, but they act like one center-tap output transformer."

If there was any doubt about the greatness of the McIntosh unity-coupled output circuit, the MC2102 and the MC2000 should settle the matter. For the first time, the Mac circuit has appeared in fully modern state-of-the-art designs, delivering clean, clear sound, natural harmonics, extended highs, and bass with balls. Why, the MC2102 sounds as good as a McIntosh solid-state amp!

Just teasing, Larry.

So I'm keeping the MC2102. It's almost as powerful as the MC2000, and I found it even better-sounding in some respects—or perhaps I should say, more to my own personal tastes. It's almost as handsome, and a little less showy. The clincher, of course, is that the MC2102 sells for less than half the price of the MC2000.

I love turning on the amp at the end of the day as I start to prepare dinner, choosing music for the meal. (Our listening room adjoins the kitchen.) Let's see...What would most amuse Marina? Ukulele Ike or Bing Crosby? The Mills Brothers or the Boswell Sisters? Al Bowlly with Ray Noble or Sam Browne with Ambrose and His Orchestra? Fremer favorites all. Life is sweet.

McIntosh produced the original MC275 for 12 years. This new Mac tube gear may have just as long a run. Only Sidney A. Corderman could have designed it. Only McIntosh could have built it.