Primare A34.2 Class D Power Amplifier

Don't Call It Digital

Equipment report
Solid-state power amplifiers
Primare A34.2
Primare A34.2 Class D Power Amplifier

My Magnepan 1.7s have been leading something of a double life for the past year or so. I wouldn’t exactly say they’ve been rampant cheaters, like, for instance, Donald Draper, but they have been carrying on with mates of various persuasions.

On the tube side, the 1.7s were cavorting with VTL’s TL-5.5 Series II Signature preamp and ST-150 power amplifier (which I reviewed quite favorably in Issue 251), while the Maggies’ solid-state playmates were Sutherland’s N1 preamp (review pending), and the Primare A34.2 under consideration here.

Using Primare’s proprietary UFPD (Ultra Fast Power Device) technology, what Primare has developed is an amplifier delivering tremendous speed and plenty of power (150Wpc) in a relatively compact (16.9" x 4/13" x 15.15", and just 23 pounds) and affordable ($3000) package. And should you be after essentially unlimited power, for, say, either home-theater use or for extremely low-sensitivity speakers, the A34.2 can be operated in a bridged-mono mode to crank out 550 beastly watts.

But brute force isn’t exactly the point here. Although the A34.2 is certainly capable of slamming hard, in my experience it is also capable of fine resolution and finesse.

One example I’ll cite is Joni Mitchell’s “The Circle Game” from Ladies of the Canyon [Reprise]. Her marvelous third LP dates from 1970 (her next would be Blue), and the sound here is quite good. As Ladies is still more folk- than jazz-oriented, acoustic instruments are her main accompaniment, and I marveled at hearing the golden purity and presence of her young soprano, along with the truly beautiful, harmonically rich ringing sound of her Martin acoustic, both of which the Primare reproduced with directness and natural balance against the backdrop of a large, notably airy stage.

The word “neutral” is often overused to describe components, and it doesn’t necessarily mean that a design that strikes us as being neutral is going to be more satisfying than something with a more overt personality. (I actually prefer the word “transparent” to describe the gear that delivers the goods with as little of its own sonic signature as possible.) But neutral does strike me as a good word for the A34.2, as its tonal balance on this and the rest of the musical examples I’ll describe consistently struck me as neither warm nor cold, as well as highly consistent across the audible band, with no apparent peaks or valleys from top to bottom. And this was a constant whether I was using the VTL or Sutherland preamp.

Describing Primare’s design goals for the A34.2, Kevin Wolff of Primare’s U.S. importer, VANA, wrote in an e-mail: “It is unfortunate but much of the audio industry still does not understand that Class D does not mean digital, though it can. Some [Class D] designs are digital while others are not; ours are not. The analogy we have [been] working on is that of high-performance electric and hybrid cars. I used to own a Prius. While a great car, it was not high performance. The new La Ferrari is a hybrid that’s high performance for sure. Some Class D [amps] are deserving of the ‘it makes sound’ moniker, while others go beyond. We think we’re in the second category. The design ideal was not of space and efficiency but of sonic value. The efficiency advantages are bonus features. Primare’s proprietary Class D design is in its view the best amplifier design it’s ever had. This was not a compromise project but one based on a goal of producing the most natural, detailed, and musical component possible.”

Not being the most technically versed member of the TAS team, I asked Wolff for a more detailed description of the difference between digital and analog Class D. I believe that this succinct paragraph from an forthcoming Primare paper covers it nicely: “The term ‘Class D’ is sometimes misunderstood as meaning a ‘digital’ amplifier. Primare’s UFPD modules operate entirely in the analog domain. Basically, the UFPD amplifier module takes an analog input sinewave and converts it into a high-frequency pulse-width-modulated square wave for amplification. This square wave is then filtered, resulting in an amplified analog sinewave at the output.”