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Enter the Acoustic System Int. Tango R speakers from Franck Tchang of acoustic resonator, LiveLine cable and HeartSong rack fame. Streaming source was once again my customary iMac/Weiss DAC2 combo. The media player was new however and Amarra 2.0. Besides my ripped Redbook library, I wanted to decode the occasional 24/96 and 24/192 high-resolution Flac files which I'd already downloaded for good coin from Linn Records.

Amarra can now process Flac on the fly when accessed through the "open files" command in the new playlist feature - or rewrite them to Aiff to show up in the standard album interface window of iTunes. Glorious riddance to Fluke, Max or Switch file conversion rituals.

Picking on the ModWright with speakers more its own size, the previously referenced Mosfet mist was less in evidence. A likely contributor was that the amp could now stretch its legs further to begin working inside rather than outside its torque curve. On raw resolution and in-sight, it was still bested by the F5 and J2 FirstWatt low-power challengers. Given that I really didn't anticipate perfect equality, I wasn't bothered. One rarely gets something for nothing. I'd already gained a four-times increase in power over my Nelson Pass units. Surely return payment had to be made somewhere. On this debit ledger it was as a slight reduction in speed/attack, somewhat lower illumination of recorded space and less acute image lock.

ModWright KWA-100 vs. Burson Audio PP160: The $2,300 Burson is a 95/190wpc differential class A/B amplifier with Toshiba 2SC5200 NPN and 2SA1943 PNP output devices, proprietary discrete voltage regulators and an overall more compact and simple but very rigid enclosure that acts as one massive heat sink. It offers very unusual high-level inputs to boost valve amps of up to 25wpc. Its 29dB of voltage gain are then reduced to just 6dB and the tube amp sees a resistive 8-ohm load.

This was interesting. The juxtaposition became an exercise in openly declared design philosophies materializing to a 't'. Burson's amp is about complete transparency. Hence its makers added the booster function to add invisible power (current drive) to flat-chested glass amps whose sonics are—supposedly—not otherwise altered. ModWright's amp, particularly its input stage, is about deriving valve virtues from transistors. Ditto the choice of Mosfet outputs. Down the list of usual suspects—treble, midrange and bass—the Burson had the slammier grippier bass and cooler sharper top end. Far more decisive than any quantitative aspects however was a noticeable qualitative difference between both presentations.

The Burson had a crisp and dry manner of just the facts about it. I couldn't really fault it objectively. Yet artistically, it left me cold. Not bleached, the ModWright had far more white in its color palette to sound more elastic, airy, buoyant and breathing. The Burson was stiff by comparison; correct but somewhat rigid. Arguably a tad less focused and locked, the ModWright was more expansive, texturally fluffier and with my quite crystalline front end the clearly more satisfying amp to listen to. Had I been the proverbial fly on the wall in their makers' respective facilities, I imagine the Burson team obsessing about pushing measurable specs to the max; Dan Wright applying subjective gut instinct honed by years as modifier, his ears as guide.

Some reviewers pretend at meticulous objectivism. They run a microprocessor between their ears to spit out test scores with clear numerical rankings. I can only approach reviewing as a pleasure listener by proxy. With sufficient experience, one quickly recognizes signs of wrong, flawed, skewed or lacking performance. Once a component clears that basic hurdle, it's all about subjective intangibles. Which machine makes you want to listen longer? Which one gets you emotionally involved and intellectually stimulated? Pointing a finger at one to say yes and no to the other is instinctual. Child's play. Much harder is explaining why. What makes it so? In this instance, the primary difference boiled down to stance. One presentation was solid, unmoving and as such, hard not in terms of overdrawn etched attacks but how it would feel if you played Chopin without rubato. The other was breathing, fluctuating with and riding on the music. In that sense, it was soft - pliable, elastic. Objectively, the Burson had more control in the bass, more extension on top. Subjectively, the Australian more was less. The ModWright had fluidity. (The real trick would, again, be to determine why. That I'll leave to the designers.)

ModWright KWA-100 vs. Wyred4Sound ST-500
: The $1.499 Wyred is a 250/500wpc ICEpower™ switching amp with SMPS. The Danish B&O boards are modified and preceded by proprietary dual-differential direct-coupled input buffer boards which raise the input impedance and drive the output boards fully balanced.

The Wyred was considerably warmer and denser to nearly approach thick from the midbass on down. It was prototypical comfort sound of vintage Vandersteen caliber - fulsome, very robust down low, utterly non-offensive but ultimately not that finessed. Switching to the ModWright reintroduced light. Without relocating the performers, it injected space between and behind them. While the stage actors weren't pushed back, the KWA-100 still sounded deeper because there was more going on behind individual musicians when they performed in rows; and behind the total ensemble against the surrounding recording venue. Within this more apparent spaciousness, interconnectedness enhanced. The Wyred was more focused on the fleshy material aspects. If one applied uneducated Mosfet mist guesses of the sort I made when first encountering this strange term, 10 out of 10 listeners would have agreed on the Wyred. That's how unequivocal and pronounced it was.

As someone who over the past few years has 'bought into'—or was seduced to fall for—the sonic FirstWatt aesthetic and particularly their models F5 and J2, the KWA-100's character was far closer kinsfolk, just not as refined, articulate and translucent. The ST-500 meanwhile was a different animal altogether. Conceptually it belongs to the powerful EL34 push/pull clan. Those after its traits without tolerating the maintenance of glowing bottles would likely never think to look at class D. I'd generally agree with that reflex. In the case of the Wyred, they'd simply be so very wrong.

Adding it up: Clearly powerful, surprisingly agile, obviously fluid and just modestly warm, Dan Wright's KWA-100 is a very fine performer whose minor softening of resolution and articulation seems deliberately subservient to fluidity. That's the tie-in with premium valve amps. If that's the contribution of Allen Kimmel's voltage gain stage, it successfully does clone that aspect of tubes. Very unusual for a (relative) muscle amp was the amp's brilliant showing on the 98dB single-driver Voxativ Ampeggio. The 60wpc Nagra MSA's modulometer had mostly shown median output voltages of 0.06 watts with 0.6-watt peaks. You'd so not expect a 100-watt plus amp to come on song under such conditions. The ModWright not only did, it did so with flying colors.

But there was more to this story...