McIntosh and Autoformers. . .?

OTL stands for Output Transformer Less. These are tube amplifiers with no output transformers.

Thanks all for offering clarifications about the DC-blocking capabilities of the autoformer - I was wondering how this could be so in the absence of a secondary coil. Nealhood, just as a side note, I believe Mac still claims 35dB of negative feedback with their AT designs. Also, why should we consider AT's "mandatory" for OTL's, provided the partnering speaker presents an >8 Ohm average impedance?

Hantrax, ive heard both the 202, 352 and 402 on b&w N803s. Yes the 202 sounds very similiar to the 402. I think the 402 is overkill for N803's and below. That said, you will get a higher signal to noise ratio with the 402 resulting in a slightly quieter (darker) background at high levels. I say "slightly" because these are very quiet amps to begin with.

Ive heard the MC6900 amp section is nearly identical to the MC202, although both units are the same weight. I now own the MC202 and love it with my N803's.

Unsound - I have to admit I am not that bad. I feel Stereophile's value lies not in its advice, but in its comic relief.

You are right Zaikes. With speakers above 8 ohms there is a lesser need to consider the AT. I am not sure just where the crossover point of diminishing returns lies but I would probably pick 10-12 ohms. So even with an 8 ohm speaker I personally think the benefit of an AT could be considerable.

Even though McIntosh claims 35db feedback in their amplifier the fact is that, with a relatively low impedance speaker such as the Magnepan, the driver circuits will be working harder, pushing themselves closer to their limits so to speak, as well as the output transistors. Feedback aids this process. With the larger operating envelop and higher output stage currents we get negative attributes such as higher transient modulation distortion and, for lack of a better term, some amplifier signature.

With the AT in the McIntosh, I would not think the driver and output circuits will not be operating as widely in their envelop. Less driver swing, less output stage current, thus less dynamic distortion and less of a "signature". Keep in mind that some of these distortions are hard to characterize and I am not an expert. The propeller head on Audio Asylum may be good site for further discussion.

I see that Paul Speltz has posted on this thread. I highly recommend his advice on amplifier/speaker compatibility as he not only markets the "Zero" AT but also has much experience in their application. There is a couple reviews of the "Zero" in press; one on the "TNT" audio site and one in the January edition of AudioXpress magazine. I think its January, could be off a month though.