I have one and it's a very good amp. However, that is running in balanced mode using a transformer for phase splitting. In single ended mode it's not the same amp. McIntosh does not use a typical type of setup for phase splitting. Rather they feed the input into 1/2 of a triode to invert the phase and use that out of phase signal for the other half of the drive signal. Since this entails an RC network it means there must be some phase shift though I have not calculated or measured where this would be.
If using the balanced input this is bypassed and the signal is sent directly to the driver stages. This of course requires that the signal be differential and not just impedance balanced. I am using a pair of Lundahl LL1544A transformers wired 1:2 with a center tap to split the phase, with each side being 1:1. This transforms the amp IMO from being pretty good to excellent. It has, to my ears, more of the mid range purity of a good SET but of course still has the power and punch of a push pull amp. Mine will make just under 100W into 8 ohms at clipping, 1kHz, 1 channel driven.
If you get one of these, do your best to feed it a full differential signal. You will be rewarded with an excellent sounding amp that is reliable, cool looking and will likely hold it's value better than most. I do not like the speaker connection layout but in use they cause no real problems. Mine had the terminal strips and have since been replaced with Superior Electric binding posts. It has been 100% trouble free since purchased, which I believe was about 2004. I'd have to check the receipt.
mike
