Pre/Power Amplifiers

With over 400W/8ohm on tap, and some 55A in reserve to support over 3kW into the lowest impedance loads, the M400MxV will pull nearly double that from the wall in use. Even idling, the rich bias current, together with other losses, amounts to 77W being sunk into its thick copper and alloy chassis as waste heat. And this, in tandem with D'Agostino's relaxed application of corrective feedback, means the M400MxV has a very long warm-up time.

When first taken out of standby, a 'cold' M400MxV shows a relatively high 0.42% distortion (1kHz/10W/8ohm) but over the first hour or so this reduces to 0.18% [black infill, inset Graph] as the metal mass, and multiple parallel power transistors, slowly warm up to about 42oC in a 20oC living space. There are measurable differences in distortion over the next 12 hours by which time the thermal latency is almost entirely resolved, and the distortion settles out at 0.085%/10W [beneath the Y axis here]. PM