McIntosh MC2102 power amplifier Page 2

My friend Lars Fredell mistook the MC2102 for the Big Mac.

"Well, I see you decided to buy an MC2000 after all," said the Swede, who had reviewed the MC2000 for Ultimate Audio.

"No, Lars, it's the MC2102. And it's less than half the price."

"Had me fooled for a minute. I see that the meters are smaller and the entire unit is smaller, too. It's a beautiful amp."

Indeed it is—even without the titanium-clad chassis.

Another manufacturer visited me a few days after I'd taken delivery of the MC2102.

"Gosh, I love those McIntosh amps. Look at that stainless-steel chassis. I don't know how they do it."

The stainless steel has a silvery, mirror-smooth finish that reminds me of the Proof Sets I used to collect as a kid from the US Mint. Did I miss the MC2000's titanium? Nah, not much.

The MC2102 weighs 88 lbs and measures 17" wide by 10" high by 17" deep. It's small enough that I can set it atop one of my record cabinets. This is one amplifier you want to look straight in the eye.

As in the MC2000, the KT88 output tubes show through a clear window (the faceplate is glass). As Lars noted, the power-level meters are smaller, but have the same blue illumination, a Mac tradition. (You can turn off the blue lights, but why would you?) Missing are the massive gold-plated rack-mount handles, replaced by a simpler but elegant metallic trim. The difference in weight is mainly accounted for by the single, shared power-supply transformer.

The speaker output terminals are WBT—one common, negative connector per channel, plus positive transformer taps for 8, 4, and 2 ohms (in regular stereo mode). There are balanced XLR inputs and gold-plated unbalanced RCA inputs. The tube sockets are ceramic with gold-plated pins.

As on the MC2000, inverted cups cover the bases of the eight KT88 output tubes, to promote convection cooling.

"The tube chimneys are a Sidney Corderman touch," Larry Fish pointed out. The heat goes straight up. To keep the tubes running as cool as possible, I left the cage unattached.

Only six years ago, with the MC275 reissue, McIntosh was saying that they were producing tube gear only for commemorative purposes—their real business was the solid-state stuff. How times have changed! I couldn't resist teasing Larry, who loves his transistors.

"Some people prefer tubes," he admitted. "As long as they do, McIntosh will offer tube equipment."


Larry caught sight of the 3.5Wpc Sun Audio SV2A3 single-ended triode amplifier in my listening room.

"If the McIntosh circuit sounds so good," said Fish, "it's probably because it's very close to the triode circuits you seem to like so much."


Larry seemed to be warming to tubes. A little.

"In most conventional tube amplifiers," he continued, "you take power only from the plates of the output tubes. In the McIntosh circuit, you take half the power form the plates and half from the cathodes, drawing power from both sides of the tube."

"Easier on the tubes?"

"Yes, it seems to extend their useful life. But the big thing is that we get high power with low distortion."

The patent on the McIntosh circuit has long expired, so other manufacturers are free to copy it. But they'd also have to copy the specially wound output transformers—not so easy.

McIntosh winds its transformers in-house. This is unusual, if not unique, even during the "golden age" of tube amps, the 1950s and '60s. To implement the Mac circuit, not the usual two, but three transformer windings are required: two primaries (one for the plates, one for the cathodes) and a secondary. The two primaries are spun bifilar (ie, two strands wound together) for a close, turn-by-turn coupling. Hence the name: unity-coupled output circuit. The cathode winding provides near-instantaneous local feedback, which, according to Larry, reduces distortion at the frequency extremes.

"So that's the reason for the lack of soggy bass and soft highs?"

"There you go with your adjectives," Larry laughed. "But yes, I guess so. Feedback correctly applied."

He likes to needle me on the topic of feedback.

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