Dan D'Agostino Relentless

In Serinusland, smooth sailing has never been guaranteed. Some months back, for reasons not yet determined, my Stromtank S 2500 Quantum MK II power regenerator¹ began to hum mechanically-sometimes steadily, sometimes with a pulse-whenever I turned on battery mode.

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Simultaneously, the Dan D'Agostino Master Systems Momentum HD preamp's power supply began to hum.² I could listen through the hum-it wasn't that loud-but silence between tracks was a thing of the past, and rarely was the noise in the right key.

After Stromtank's remote diagnostic and repair procedure failed, Stromtank Chief Engineer/founder Wolfgang Meletzky left Berlin for a previously scheduled visit to D'Agostino headquarters in Arizona. Tests there revealed that Stromtank and this D'Agostino preamp mated perfectly, without generating hum, buzz, pulse, or anything else. With fingers now pointing at the preamp as perhaps defective, I returned it to D'Agostino HQ for a thorough going over. It and a different Stromtank S 2500 Quantum MK II mated perfectly, in blissful silence.

At that point, the two companies arrived at independent decisions. Stromtank decided to send me an S-4000 ProPower MK II so that I could try using it to power everything in my system, including the mono amplifiers, and report my findings in Stereophile.

D'Agostino explained that because a replacement for the Momentum HD preamp was in the works-in the form of the Momentum C2, which was introduced at Munich High End 2024-it made no sense to send the Momentum HD back to me.

Instead, D'Agostino President Bill McKiegan asked if I might be interested in writing the first US review of the top-line, three-piece, fully balanced D'Agostino Relentless preamplifier ($149,500, plus $19,500 for the optional digital streaming module), which since its 2021 introduction had only received a single review, in Europe.

Me, review a $150,000 preamp? This was not a kid in a candy store-scale event. This was a kid let loose in a big-assed candy factory-scale event.