Reviewer: Srajan Ebaen
Financial interests: click here
Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Qobuz Hifi, Tidal Hifi, Fore Audio DAISy1, COS Engineering D1, Aqua Hifi Formula, AURALiC Vega
Preamplifier: Nagra Jazz, Wyred4Sound STP-SE Stage II, Vinnie Rossi LIO (AVC module)
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1 monos, F5, F6, F7; Crayon Audio CFA-1.2; Goldmund/Job 225; Linnenberg Allegro monos; Aura Note Premier; Wyred4Sound mINT; Nord Acoustics NC500 monos
Loudspeakers: Albedo Audio Aptica; EnigmAcoustics Mythology 1; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Druid V & Submission; German Physiks HRS-120; Eversound Essence
Cables: Complete loom of Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Black Cat Cable redlevel Lupo; Ocellia OCC Silver
Power delivery: Vibex Granada/Alhambra on all components, 5m cords to amp/s + sub
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands [on loan]
Sundry accessories: Acoustic System resonators
Room: 5.5 x 15 metre rectangular space with double-high vaulted ceiling and stone-over-concrete flooring
Review component retail: £999

Audiopill: "Not in my house. Over my dead body."
Audiophil. "I got it on eBay for 70% off. I'll buy you a ring with the savings."

Use your imagination to continue this conversation. It's easy to see how Audiopill and Audiophil don't really see eye to eye. The same might be said about PC/Mac and DAC whenever USB connects the twain. They do shake hands and even talk to each other; just not necessarily nice.

Audiophilleo to the rescue. This dapper chap jumps into the breach as mediator; to get Audiopill into the game and Audiophil out of the dog house. If need be (cough), this acquisition could remain discretely hidden behind the existing gear altogether. Invisible. Woof.

Despite galvanic isolation; despite supposedly jitter-immune resampling schemes; despite mil-spec femto clocks... many a DAC sounds better when USB first runs through an intermediate black box. This type device is said to act as a noise stripper, re- or pre-clocker. There does not seem to be unanimous consensus about exactly how these audible improvements come about. What we can say without grasping is that nobody expects Apple or Hewlett Packard to install audiophile-approved USB cards with linear power supplies in consumer-grade computers. Meanwhile buyers of fancy DACs expect—and have a right to—that their decks operate with immunity regardless of what USB throws at them by way of computer-generated switch-mode power supply and other noise traveling down the USB ground; and irregularities in USB package deliveries.

Here it becomes a bitter pill when a mysterious black box calls bluff on said immunity. Rather than pretend at a full understanding of the involved 'why' and 'how', let's just point at plenty of anecdotal evidence that the best of these black boxes really do make a difference. Of course how much depends on the quality of your DAC (how immune is it already) and the resolving power of your overall system (how much will it magnify potentially small front-end improvements).
The display and preamp functions distinguish the Audiophilleo 1 (not reviewed) from the Audiophilleo 2 (reviewed).

Audiophilleo 2 without display or extra features. Its included USB cable is a generic, not the Wireworld UltraViolet of the costlier Audiophilleo 1 .
Today's li'l box is a refinement of one of the originals thus very early examples of this breed. It now runs on battery power and new custom firmware; eliminates one USB cable; includes fixed-frequency clocks; and, in its costlier guise, needn't even be black. And it's not a USB/USB bridge either. It's a USB-to-S/PDIF digital converter which outputs on the superior BNC connector.

Docking a deck to a DAC.
The PurePower lipoly battery option powers only the clocks and differential output stage. It still runs the ARM processor on the USB input transceiver off 5V USB power. Because relays isolate the battery power from the USB input, no separate charger supply is necessary when after 15 hours of pure battery play, charging kicks in whilst play continues. Whenever there's no signal, the batteries recharge automatically to be topped up for the next session. How do Audiophilleo avoid a second digital cable? By using a BNC/BNC or BNC/RCA adaptor. Now their little box docks directly to your DAC's BNC or coaxial input. [See adaptors at left.] Audiophilleo report "very good results with the Chord Hugo via the S/PDIF input." Again, that a deck of Chord Hugo pedigree could be improved by a small red, blue, white or black box with matching battery supply could be a bitter pill to swallow. Thankfully even married reviewers don't consider the thin skins of makers or users. Those considerations only factor again when it comes down to their own households. Yelp. These Youtube videos do their own barking if you're hazy on how certain features work. With its 24/192 word-length/sample-rate limit, the Audiophilleo 2 MkII "is a generation removed" from the Audiophilleo 1 MkII SE. That supports 32/384 but is still a generation removed from the latest craze of 768kHz number's warriors. But them numbers, they be escalating endlessly. Public perception equates bigger numbers with better performance and manufacturers seem only too willing to supply them. The result is an endless miss of catching up. Meanwhile very few recordings are mastered beyond 24/96. Go figure.