Audio Research DSI 200 integrated amp

About the McIntosh MA 6600, I used to own one and felt that it was good only up to a certain volume. Above this level, the sound is in tatters - ragged, congested, collapse of soundstage - in a word, unbearable. The level at which this occurs would depend on your system and you will know when you have reached this level as you can easily hear it.

Hi Jimmy,
I knew it was the amp because everything else was working well until I changed it. My previous amp was the Krell 300i integrated and I was looking for a warmer sound. In the showroom, I guess the dealer knew how to keep the volume down as indeed, it sounded good then. Back home, things were still good but orchestral crescendoes just melted before my very ears when i crank it up to realistic levels. I changed the Mac to a Levinson and the problem was gone.

Yes. The dynamic headroom was indeed restricted. It was just a poor match for my speakers, MBL 121,which were a bear to drive - low sensitivity at 84 dB with impedance dropping to 2 ohms at times. The Mac power does not double with halving of the impedance.