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A sidetake on NJR's Muses. I'm no opamp expert to know the lay of these lands. Thus I took note of the $16.500 XP-30 statement preamplifier from Pass Labs: "... One of the basic tasks facing any preamp is volume control. The pecking order as far as sound quality has traditionally spanned the range from the lowly conductive plastic pot to a high-quality resistor-based stepped attenuator.

"But recent developments in electronic volume control have upset the status quo. The XP-30 uses the new NJR Muses 72320 IC, a two-channel electronic volume control with an internal resistance ladder optimized for low noise and sound quality. Apparently a few resident audiophiles at New Japan Radio Co. lobbied successfully for some high-end parts and the result was the Muses series of op-amps including the 72320 volume control...
"... My own listening tests confirmed that the Muses volume control at least as implemented by Pass Labs is top notch. It went up against my reference, the Experience Music Passive-Aggressive autoformer volume control based on Dave Slagle’s silver autoformer modules and perfect for a digital front end. It’s a tough test for an active linestage. Consider that line-level output is a nominal 2V for a CD player or DAC, sufficient to red-line typical power amps with an input sensitivity between 1 and 2V. Therefore the signal needs to be attenuated by an active linestage before it is amplified again - not an ideal situation. The XP-30 is one of the few linestages that could hold its own in such a head-to-head competition." [From Dick Olsher's The Abso!ute Sound review.]

That's quite an endorsement for NJR silicon. I had no idea its appeal reached this far into the ultra high-end. Another endorsement came from former contributor Michael Lavorgna who since joined the Stereophile team. He bestowed upon the Xonar Essence One Muses Edition AudioStream's Greatest Bits award. For further brass tacks on this very subject, Asus subsequent to my November review sent me samples of both standard Essence One and Plus. This facilitated highly convenient A/B comparisons to learn what sonically distinguishes the versions. I connected all three to a luxury preamp and simply toggled its inputs whilst reseating the slinky Telos Audio USB cable and resetting the iMac's output to either Speaker (for Plus & Muses) or S/PDIF output (basic).

The outcome of this exercise was as basic as it was educational. Climbing up our three-tier ladder predominantly affected textures and image density. The basic machine was driest and the tonally lightest. Coming down from the dearer versions this dryness felt slightly pinched as though it weren't breathing as freely or deeply. Textures going up became wetter and more redolent. Density grew denser. Images became more robust and heavy as though they were taking up more space. This wasn't a literal phenomenon of gaining girth to turn skinny performers into lardies. It was more akin to occupying additional air molecules in the same amount of space if that makes sense.

OSX 10.8.2, Audirvana 2.4 in direct/integer mode set to 176.4kHz

As it turned out, the hot buy of the three must be the $699 Plus. Separating it from the basic was a broader gap than what occurred above it. Yes the Muses was warmer still. It became even more deeply incarnate, more descended into the body down to the toes (rather than being a bit dissociated as though 'in the head' and thus not fully present if we dealt with humans). That said, for many in the target audience those last $200 for the Muses Edition could really guild the lily.

ModWright KWA100SE, AudioSolutions Rhapsody 200

More important I thought was how relatively close these three versions performed. Hearing them side by side underscored the solidity of the basic circuit. It also caused delight about the fluidity and ease whereby one version becomes the next simply by swapping out a few opamps. It's a type of 'nobody left behind' soldier's ethos. Someone capable of parting with $1.500 for this type of DAC ought to head straight for the Muses. It's the obvious thing to do. Ancillaries should be suitably refined to get the most from those luxo critters.

Someone with a far tighter budget where a c-note weighs heavily has the $599 machine for the highest value. The majority of the firm's declared target audience—first-time audiophiles—meanwhile ought to fix their eye on the $699 Plus. In this game of three thrones it gets you 90%+ of the way - plenty good for anyone with a full life beyond just fretting about hifi. As suspected earlier but confirmed now with the actual machine on hand, the fully upgradeable $599 version gets our Realsization Award for setting new standards in its class. The price to pay for such excellent value? Shopping resources. Until Asus penetrates regular brick & mortar shops of the audiophile persuasion, the Xonar Essence One will sell through its current IT outlets and related online portals. Contrary to what one reader insinuated—that you can't actually buy this machine—it simply takes a bit of chasing it down. So get into the courting mood and remember its moves...
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