VTL MB-450 Series III Signature monoblock power amplifier
The VTL MB-450 series began life in the late 1980s as the Deluxe 300, a pair of which I once owned. Over the years the basic design has been improved and modified, in the forms of the MB-450 (1996) and the MB-450 Series II (which I reviewed in January 2008). The tube complement remains the same: eight 6550s in the push-pull output stage, a 12AT7 input tube, and a 12BH7 driver. Into a 5 ohm load, the MB-450 III is claimed to produce 425W in tetrode mode or 225W in triode, from 20Hz to 20kHz.