Solid State Power Amp Reviews

A century ago, pioneering psychiatrist Carl Jung had a wild encounter with the power of sound. "In a village on the way from Lake Albert to Rejaf in the Sudan we had a very exciting experience," Jung wrote in his book Memories, Dreams, Reflections. He goes on to describe his participation in a tribal drum and dance ritual. "Night had fallen ... when we heard drums and horn blasts. Soon some sixty men appeared, martially equipped with flashing lances, clubs, and swords."

Back in 2016, I documented the rise of class-D amps using the early TriPath technology. Used in the Bel Canto eVo 200.2, TriPath cracked open the door to the High End but was never admitted due to a dim and opaque treble. The second wave was based on B&O's ICEpower technology, again via a Bel Canto amplifier, the Ref1000M monoblock. ICEpower had more credibility and was accepted by many but, often, only with, ahem, due consideration for size and efficiency. There was an explosion of new class-D amps in 2016 when Stereophile featured glowing reviews of Bel Canto's e.One Ref600M monoblock, Theta's Prometheus monoblock, and NAD's Masters Series M22 stereo amp, all based on Bruno Putzeys's Hypex NCore technology modules. Finally, it seemed that class-D was "in the room," though, even to this day, there remain critics and quibblers who continue to deny them as true high-fidelity products.

Well, time does not stand still and neither did Bruno Putzeys. He, along with Lars Risbo and Peter Lyngdorf, had founded Purifi in 2015, and in 2019 he unveiled the Purifi Eigentakt power amplifier modules.

There was a period in the 1970s when many pop ballads that should have had understated arrangements instead turned grandiose and even maudlin. Take Gilbert O'Sullivan's sensational single "Nothing Rhymed" (a track that went deep for a pop hit, referencing famine, duty, and morality). Soon after the start, O'Sullivan's piano is overshadowed by a loud, saccharine string section.

Another example is "Lotte," German singer Stephan Sulke's portrayal of a dying love affair. The devastatingly wistful chanson is burdened by a mawkish orchestral track—the equivalent of glitterbombing an Edward Hopper painting.

Contrast this with Roberta Flack's definitive version of Ewan MacColl's "The First Time Ever I Saw Your Face." Apart from Flack's voice and her emotional delivery, the gently strummed guitar and quiet piano do all the heavy lifting. An unhurried double bass and a couple of minimally bowed string instruments leave swaths of negative space, helping to give her interpretation its hushed, reverent character.

I reflected on all this after spending several months with Balanced Audio Technology's REX 500 solid state power amplifier ($25,000), which has more in common with the Roberta Flack track than with the bombast of "Nothing Rhymed."