Changed. The H1 had always played the more silvery/platinum realms of speed, sparkle, separation and a leaner tonal balance. It had put higher priority on charge, resolution and microdynamic nuance. The D10 made a course direction. Like a physically fat power cord with serious copper gauge fronting an entire system with matching speaker cable can make a reading more autumnal—more half shadows, with a statelier gait, greater weight, softer transitions and heavier bass—so the new 5-in-1 had morphed from energetic spunkster to more mature fuller statesman; just like this tune.

This change was quite pronounced. It easily reset by returning to the H1. From the specs we know that COS haven't changed converter silicon. They still champion BurrBrown just as they have from the very beginning. Yet circuit tuning, possibly an overhauled output stage and/or altered power supply have grafted onto that DAC a different voice. It's moved from the Chord/Questyle terrain into Aqua/Denafrips turf, from Raal to Audeze headphones, from vintage speakers like early Thiel to Serblin-era Sonus faber. In contemporary speaker terms, the H1 was our Acelec Model 1 monitor, the D10 our new sound|kaos Vox 3awf. From its very opening, the next tune introduces snappier rhythmically more incisive elements to stand in for the H1 polarity.

Once I'd focus down on the D10 as fixed DAC, I could qualify the extent of the overlap with two Denafrips converters on hand. For now I'd phone in more because…

… like any other DAC, the D10 proved not to be a source agnostic. No religion truly is. Be it a Denafrips Gaia, Innuos Zenith, Mutec MC3+ USB or the resident Soundaware D300Ref, in my experience serious external reclockers improve USB; always! The €5'500 Terminator Plus isn't immune. The €9'000 COS D1 isn't. Nothing come through has been. Now the D10 agreed. How so? To let it run nonstop overnight, I swapped sources. Instead of streaming files through the iMac's maximized 32GB RAM buffer—that's controlled by Audirvana to spin down the internal FusionDrive—the super-cap powered Soundaware read files off a 128GB SD card. Those the D10 clocked not by USB but AES/EBU or I²S. The headphones at first remained the very keen Susvara. Swapping to digital XLR via an Allnic cable injected into USB's thicker warmer voice decidedly more separation, illumination and microdynamic gradation. Moving to HDMI for I²S via Audioquest Coffee cable with battery-charged bias then notched up clarity/precision by another percentage point. As always for me, SD card streamed via I²S trumped USB by a clear margin. With SD card, there's no Internet, no hard drive, no massive OS, no switch-mode power supply. Not making all that noise in the first place is superior to trying to filter it out after the fact. No need to say sorry.

Changed 2. In XLR/HDMI mode, the D10 felt ideally balanced between the ancient adversaries of weight/speed, color/transient, density/separation. Those are either/or worriers. Wanting more of one invariably subtracts something from its opposite. Finding the middleground to represent all aspects 'equally'—that's as much myth as 'neutral' and always down to subjective perception—tends to be at the heart of our audiophile system tuning. Here maturity eventually wises up. Wanting it all implies that extremes can't be tolerated. Otherwise their gain becomes something else's pain. For my ears, this post-USB course correction had even our old sealed LCD-XC Audeze with their warmish chocolate tuning not feel overdone. Instead they simply proposed a Harbeth-type presentation. That has many admirers.