Reviewer: Srajan Ebaen
Financial interests: click here
Sources: 27" iMac with 5K Retina display, 4GHz quad-core engine with 4.4GHz turbo boost, 3TB Fusion Drive, 16GB SDRAM, OSX Yosemite, PureMusic 3.01, Tidal & Qobuz lossless streaming, COS Engineering D1, AURALiC Vega, Aqua Hifi La Scala MkII, Fore Audio DAISy 1, Vinnie Rossi LIO DAC, Apple iPod Classic 160GB (AIFF), Astell& Kern AK100 modified by Red Wine Audio, Cambridge Audio iD100, Pro-Ject Dock Box S Digital, Pure i20, Questyle QP1R
Preamplifier: Nagra Jazz, Esoteric C-03, Vinnie Rossi LIO, COS Engineering D1
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1, F5, F6, F7; Crayon Audio CFA-1.2; Goldmund Job 225; Aura Note Premier; Wyred4Sound mINT; AURALiC Merak [on loan]
Loudspeakers: Albedo Audio Aptica; EnigmAcoustics Mythology 1; Sounddeco Sigma 2; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Druid V & Submission; German Physiks HRS-120; Eversound Essence
Headphones: Forza-rewired Sennheiser HD800, MrSpeakers Alpha Prime, Audeze LCD-2/LCD-XC; stock-cabled HifiMan HE-1000 and Final Sonorous III & VI; ALO-rewired Beyerdynamic T1/T5p; stock-cabled Meze 99 Classic
Headphone amps: Bakoon AMP-12R, Vinnie Rossi LIO DHT, Eversound Essence, 2 x Questyle CMA800R
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; Arkana Research XLR/RCA and speaker cables [on loan]; Sablon Audio Petit Corona power cords [on loan], Black Cat Cable Lupo
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: Rectangular 5.5 x 15m open floor plan with two-storey gabled ceiling, wood-sleeved steel trusses and stone-over-concrete flooring
Review component retail in Europe: €2'500 (without local VAT)

The COS* Engineering D1 DAC/preamp had been a wakeup call five minutes to midnight. It caught our second-to-last award in late December just before 2014 rang out. Here was a new Taiwanese company with their maiden product. Being first to cover it, I'd started at square one. Until their Maggie Chern contacted me, I'd never heard of COS Engineering. In fact their website didn't launch until well after my review. In some ways this discovery became a reminder of my earlier encounter with Wow Audio Labs. It leaves one open to be hit hard and out of left field. The D1's stout €9'000 sticker proved perfectly justified by peak performance as both converter and analog preamp; plus the type of minimalist refined looks for which big companies hire a well-known very expensive industrial designer. [*COS = connoisseur of sound.]

Anticipating a matching power amp for 2015, I'd merely belaboured its lack of headfi. That would have made for a complete 2-box system—add speakers, cans and computer—to cover all the main bases. As it turns out, team COS already had their eyes on headphones. Their thinking was simply on a more compact dedicated 3-in-1 à la April Music Eximus DP1, Burson Audio Conductor Virtuoso or Chord Hugo TT. Their new deck is called H1. It contains a DAC with switchable USB 1.0/2.0, TosLink, coaxial and AES/EBU ports; a variable line-level output (to an amp or powered speakers); and twinned ¼"/XLR combo ports for balanced headphone drive or to power two unbalanced headphones simultaneously.

Had we expected a return of the D1's big embedded volume knob with natty LED smile, let's invoke its obvious impact on any short run's build cost due to pita manufacturability. That should explain why for the smaller H1, COS opted for a more conventional easier knob. It works just as well but avoids some machine-shop curses. For desktop/headfi purposes, a remote control became redundant to book another cost savings. Clearly the design group in Taiwan was keen to follow up their flagship effort with something a bit more 'man of the street'. To get more details meant checking back with Maggie whose flawless English and prompt responses make communications with COS Engineering a professional joy.

In prior conversations, I'd learnt how retail pricing conventions in the US and Europe plus wildly varying VAT and fluctuating exchange rates had caught the Taiwanese unawares. Like many new companies, they'd underestimated margin layers. Discussions with potential distributors in the wake of releasing their highly styled D1 alerted them to lack of oxygen in their price sheet. This became another reason for why the H1 plays it just a bit less flamboyant on style. For something supposed to sound great, nobody wants to price themselves out of the running just for extra cool design cues. Just so, for the H1 COS still struggled mighty hard on their enclosure finish. "Because we suffered during working with the vendor who produced the D1 case, we decided to change suppliers for the H1. Unfortunately, things didn't go well with this party either. Their first batch didn't come out at the quality we stipulated so we have to push back our first run from January to March."

When asked what the issues were, "the new vendor didn't make the case exactly to our specs to be dimensionally off. We need better than sub millimetre tolerances. I don't know whether I told you that Stephen and I worked in the same company before, at a public firm in the AIDC industry. Though our products then were in plastic, most of them needed to fulfil the IP standard so we're pretty picky about the precision of each part of the case.

"The D1 was our first metal case product and none of our past experiences helped. We weren't happy with the first vendor and thought the second one would be better but we were wrong. When we worked in plastics, the vendor would always raise concerns if they foresaw possible production issues whilst reviewing the blueprint files.

"Alas, the vendors in this particular metal-work industry seem to simply take the design, then go ahead producing it. Issues show up only after the fact. In addition, they have different ideas about precision which really bothers us. We already reviewed their second H1 sample. Though there was an improvement over the first, it still didn't meet our expectations. I guess it's still a long way to pay the tuition." By August 29th, Maggie's excited email ended in this emoji. I knew right off that now we were set. "Our H1 is finally ready. Yes, finally!!! Are you available?" Hell yes I was.