Ces4x4,
Yes, I have. I was able to compare it directly to Quicksilver 90 watt silver monos for several months, using Spendor SP100 speakers as well as Celestion SL6s monitors.
The quicksilvers gave a singers head a more 3D quality, which was good. The downside of the Quicksilver (besides frequent blown fuses) was that the tonal balance was so colored compared to the Mac. Plummy bass, and slightly rolled off highs. (and believe me, the Mac is rather mellow)
I think that what I missed the most was the overall "architecture" of the sound. Compared to the Mac, all other amps I have tried lacked the sense of solidity, maybe you could say gravitas, of the Mac. I owned an MC 300, and it was the same story, only since the MC300 was a much newer design, it had a lower noise floor, and was a bit silkier, and I would say the 2105 is a little more midrange-prominent, in the way that tube amps sometimes seem to be. Also, compared to the 2105, the Quicksilver was lacking in image height. The overall picture seemed to be a little vertically compressed.
In comparison to a Pass Labs 250.5, it sounded rich and colorful, while the Pass amp, with 4 different speakers I owned, sounded thin and sterile.
I'm sure that you have noticed that these amps still command prices up to 2x their original retail. Some of that is simply a collector's nostalgia gone wild, but there is also a good solid reason. It is a classic amp because even by today's standards, it sounds great.
I would also like to mention that last year, I had it fitted with abn IEC outlet so that I could get rid of the ancient zip cord that was originally used. I now use a Pangea AC-9 SE. The amp is quieter, and the bass is more powerful.
Pull the trigger- you won't regret it.
