Jeff Genzler is one of bassdom’s most seasoned amplification gurus, having offered up a host of innovative designs over a three-decade-plus career.
THOUGH MANY MANUFACTURERS HAVE tried, there’s simply no way to perfectly duplicate the sound of an all-tube head using solid-state components. Those who dig the plush response, rich harmonic color, and sweet overdrive potential of tube circuits are thus forced to accept tube heads’ limitations, most painfully their much heavier weight compared to solidstate amps. But what makes tube amps so heavy? First, power amp tubes are physically large and require airspace to dissipate heat, so most tube heads are big. Second—and most important in terms of weight—tube amps have so far needed two heavy transformers to operate: An output transformer for impedance matching between the power amp and speakers, and a power supply transformer to step-down and distribute the power from a wall outlet. The revolutionary Peavey VB-3 all-buteliminates one of these transformers, and the weight savings are enormous. It accomplishes this feat with a switchmode power supply (SMPS). While the technology is incr