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 Formula, Fore Audio DAISy 1, 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 with DHT module, COS Engineering D1, Wyred4Sound STP-SE Stage 2
Power & integrated amplifiers: Pass Labs XA30.8; FirstWatt SIT1, F5, F6, F7; S.A.Lab Blackbird SE; Crayon Audio CFA-1.2; Goldmund Job 225; ; Aura Note Premier; Wyred4Sound mINT; Nord Acoustics One SE UP NC500MB; 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, Rethm Bhaava [on loan]
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: €4'000

Emoji queen Maggie Chern's email images set the mood. Clearly COS Engineering's always-on cookout was about to serve up something new. Regular readers know that I reviewed then bought their D1 DAC/preamp and subsequently wrote up then acquired the H1 fully balanced headfi converter. I like to put my wallet where my pen pressed hard. Here it makes me a fully paid-up COS champion. My inner betting man was certain that Act III in this Taiwanese opera would be a class A/B mono amp inside the small chassis of the H1 whose RCA outputs double as minimalist preamp without remote. Add amp and presto, a full mini system. But, Maggie's emoji blew kisses not at that but the new D2 DAC. It's available with/without volume; so variable or fixed gain. This bet I'd have lost. It's why my gambling man stays in where he can't do any damage. Dommage as the French would say. Too bad. Not! After two Blue Moon awards, anything COS gets me excited. I'd simply not expected another DAC.

Playing ping pong emails with Maggie, I learnt why. Though an amp was on the drawing board, the quicker project to final was the D2. It's less coin than the D1 by shaving off cosmetic extravagance. As COS learnt after their D1 left Kaohsiung Port under a €9'000 flag, for a young hifi company it's not easy to grow a business with a costly first product. That's why they worked hard to bring in the later H1 at €2'500 before VAT. With the D1 having set a very high bar for designer styling, COS went through a few suppliers before the simpler H1 case passed inspection. Once it went into production, their engineers looked at how to repackage the D1 innards into the smaller extrusion, then shrink, substitute or omit whatever wouldn't fit its size or target bill. With the H1 already containing a D/A converter scaled down from the D1, the D2's removal of the H1's headfi amp could load up again on the digital side; or perhaps on the power supply?


It's a clever way to spread out mature tech over multiple models, each with a clearly defined user profile. Like the D1/H1 do, the D2's now optional volume operates in the analog not digital domain. There's no bit stripping or resolution loss at low levels. If you're still hazy on COS the name, it's short for connoisseurs of sound. And they're not just saying that. When I told Maggie of my assumption that when they first built the D1, they had no notion yet of our high-end's deeply layered distributor/rep/retail margins, "you're totally right. We had no idea. If we knew, the D1 might have been born with a different look" - "one less costly to make" would complete her sentence. It's reminiscent of Mola-Mola's Kaluga amplifier. Its wave-shaped chassis went through three machine shops before it passed muster. That not only delayed first production but weighed down the retail price. Anyone missing in the D2/H1 the D1's push/turn knob set into a massive baffle and the LED half circle below must acknowledge their disproportionate impact on the sticker. If those style elements are important to you, the D1 remains the one and only. Pay up!


The COSway to the D2. To recap company history, COS was founded by friends Stephen (Gong Xixun), Oliver (Wang Fuquan) and CC (Fang Zhiquiang) who had previously worked at the same medical electronics firm and shared a love of hifi and good sound. The D1 was preceded by 3 years of internal R&D which included writing their own filter algorithm. Much critical listening used Stephen's office system of Sonus faber Amati speakers, Goldmund Telos 600 monos and Nottingham Spacedeck turntable*. The H1 took two years to perfect. This included three different machine shops until they could sign off on the casing. Whilst they would likely prefer to move faster, their standards refuse visible screw heads, bent sheet metal and even minor anodizing imperfections. This imposes limitations on how quickly any breadboarded circuit accompanied by detailed 3D drawings can manifest in final production. As all women know, beauty takes time. As all businesses know, time is money. As small hifi firms know or learn soon enough, to compete with Apple on finish and industrial design without Cupertino's vast engineering department, resources and FoxConn manufacture is no walk in the park.
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* Other gear owned amongst the principals includes, for sources, a Blu/DAC64 duo from Chord and a N°30.5/31.5 combo from Mark Levinson; for preamps, a C42 and C500c from McIntosh, a N°32 from Mark Levinson and a tubed Cabernet from Supratek; for amps three MC352 from McIntosh, a DM-10 from Densen and a 2060 from Boulder; and for speakers two pairs of Stradivari and one Cremona from Sonus faber, a Kingdom 12 from Tannoy and a 6 from Dynaudio. For cables, they all favour Van DenHul. This collection of brands and models gives a good indication on their sonic preferences.
 
"This hopefully should be out by April. Our retailers reported how some of their clients use our H1 without headphones, so just as a DAC/preamp. For such users, the D2 becomes the perfect go-to model if the D1 is out of reach."
... to be continued...

COs Engineering website