For as long as I've known about high-end audio, I've put Dan D'Agostino, co-founder of Krell, on the same pedestal reserved for the likes of Frank McIntosh, Saul Marantz, Avery Fisher, H.H. Scott, and Sidney Harman. The reason is simple: Dan's the man whose achievements at Krell led me from the harsh sound of my first high-end amp into another dimension, one of truly musical sound reproduction.

To accompany my review of the Dan D'Agostino Master Audio Systems Progression monoblock amplifier elsewhere in this issue, I talked to Dan D'Agostino about the amplifier's design. I started by asking him what were some of the major differences between the Momentum and the Progression monoblocks?

Dan D'Agostino: I took the best parts of the Momentum's more sophisticated and complex circuitry and put them in the Progression, without using the same high parts count. Each stage of the Momentum's gain amplifier is separate, with input stage and driver stages on separate rails. All of the Momentum's devices are designed for maximum performance in a small package, which requires a lot more of them, and a significantly bigger input card than the Progression's. These differences create subtleties, because I'm able to run much higher current in the Momentum's front end.