Vincent Audio SA-31MK Hybrid Linestage Preamplifier & SP-331MK Hybrid Power Amplifier (TAS 208)

Audiophilia is a strange, often frustrating, yet occasionally euphoric state that, as was determined many years ago by an eminent Freudian (a fan, if I’m not mistaken, of 845-based vacuum tube amplifiers), almost always affects the male population.

But as it is with collecting Swiss watches or rare wines, driving a fine automobile, or tracking down genuine Cuban cigars, this hobby ain’t exactly cheap. It can also lead to a state known as Audiopihila Nervosa, which can wreak havoc on both one’s psyche and paycheck. (To gauge your status, take The Audiophilia Nervosa Test at audiophilia.com/features/aptest.htm.)

As certain pages of this magazine can attest, for the true audiophile, the type of guy who burns through gear faster than Tiger Woods can shout, “Fore!,” there is plenty of state-of-the-art equipment to buy (and sell) while questing for the Holy Grail. And even for those of us who can’t afford the latest and greatest, these rare birds—the Walkers, Wilsons, Magicos, and Solutions, to name but a few—not only define what’s achievable at the leading edge of our hobby; they also, like the Maltese Falcon, are the stuff that dreams are made of.

To be sure, there are many fine examples of value-oriented gear out there. Components that deliver a lot of musical pleasure at a price the average schlub can afford (as a matter of fact, that’s the entire purpose of this column). For guys like that, like me, my suggestion is to stop chasing the Holy Grail, pour a shot of single malt (a relatively affordable indulgence), sit back, and enjoy the music.

Which is something, I can report, that the newest gear from Vincent Audio allows for quite handily.

The SA-31MK linestage preamp and SP-331MK power amplifier are both hybrid designs, aiming to marry the reliability, speed, and power of solid-state with the warmth, air, and harmonic richness of tubes. Both are upgraded editions of the SA-31 and SP-331 that Chris Martens was so high on by back in Issue 173. And while those models remain in Vincent’s lineup—at $649 and $1299 respectively—the new MK versions aim to build on the sonic qualities of their predecessors while still offering strong value-for-dollar.

At $1399, the SA-31MK linestage features a new output circuit with shorter signal paths, and adds a second set of 6N16 vacuum tubes to the original pair found in the SA-31. The new model is also said to incorporate higher-grade, European-sourced resistors and capacitors, electronic volume and input controls, two more sets of line inputs, plus a brushed-aluminum remote control (a feature Chris lamented the lack of when he reviewed the SA-31).

Like its predecessor, the SA-31MK offers a few, somewhat retro features that seem aimed at the buyer who may be stepping up to his first set of separates from an integrated amplifier or receiver: One is bass and treble controls that can be activated or deactivated via a front-panel button; the other is a LOUD(ness) switch to goose up the sound at lower listening levels. (Both remained unused during my evaluation sessions.)

At $2199, SP-331MK specs out with the same power rating as its MK-less brother—150Wpc into 8 ohms, and 300Wpc into 4 ohms—but unlike that unit is designed to operate in a pure Class A mode for up to 10 watts of output power. The Vincent team’s reasoning is, “When listening to music at moderate sound levels, the power reaching the loudspeakers is typically less than 1 watt, and for serious audiophiles seeking to parse the finest details of a musical performance a pure Class A amplifier is preferred.” This is true enough in theory, but my experience driving a notoriously power-hungry speaker like the Magnepan 1.7 leads me to think of the SP-331MK as a slightly dual-natured beast (more on this shortly).

Other differences between the two amplifiers reside in the MK-edition’s new 12AU7 “tube stabilized” Class A power supply, which is coupled to a large toroidal transformer. Its 80,0000µF per channel of storage capacitance helps the amp to double its output power from eight- to four-ohm loads.

Finally, the MK model offers two sets of five-way binding posts, allowing for the addition of a second pair of speakers. Front panel SPEAKER A and SPEAKER B switches allow one to select either or both pairs. This again seems a nod to listeners who may not quite be prepared for the lack of such flexibility found on most higher-end separates.

The Vincent pair is quite similarly voiced, but I’ll start by describing the sound of the amplifier, which, as I already hinted at, does change character as it morphs from its moderately powerful Class A mode into full-on-powerhouse Class AB operation.