COS Engineering DAC Preamp D2V

I used the COS DAC2 for about 500 hours. It looks like new.  It has a full bodied, colorful sound which made voices and string instruments sound rich and alive. It is beautifully constructed. It has very precise .25db stepped attenuator with a big blue readout.  (DAC1 has tiny little LEDs which is an artistic feature but not easy to gauge repeat settings). The former U.S. distributor, Mike Powell, indicated that the manufacturer will warranty it despite it being 2+ years old.

Please note that the $1500 black version I sold was in very good condition (small scratch on top, unknown wear) not in near mint condition. It was a demo unit with multiple users.  This standard aluminum version has no marks or scratches.

Also note that it functions as a pre-amp as well as a DAC.

COS Engineerings’ D2 is built to turn digital data into real music. Armed with the company’s proprietary algorithm, D2 offers a fine acoustic aura, backdrop pitch-dark, stage expansive, instruments colorful and dynamic, and vocalists palpable. D2V is D2 equipped with volume control, sending analog signals directly to a power-amplifier. An OLED screen, which displays input source, buffer, and volume, provides instant information.

COS ALGORITHM AND DSP
COS Engineering’s proprietary algorithm up-samples original data to 176.4K or 192K, 24-bit by a process in an array of 4096 with 32-bit precision. To rule out phase contamination that may stem from the more computationally efficient IIR filter, a linear-phase delay FIR filter is chosen. This massive computation is handled by a powerful DSP capable of 3648 MMAC (millions multiply and add) per second.
BUFFER AND RE-CLOCKING D2 receives data from digital sources, whether a PC, a CD transport, or a mobile device, aligns them in exact frames with a one-second buffer, and sends them out for interpretation by the COS algorithm. The data so processed is then converted to analog signals, under the coordination of a crystal oscillator with a jitter precision less than 1ps and a dedicated re-clocking circuitry.
POWER D2 harnesses two selected switching mode power supplies with specially designed circuitry for lower noise. These power supplies work with 100~240VAC; there is no need to select voltage.
FULL BALANCED DESIGN Balanced designs are applied throughout the entire audio signal path. Even-order harmonics on the differential signal pairs are carefully matched and are thus gracefully cancelled in order to achieve the lowest possible distortions.
GALVANIC ISOLATION The galvanic isolation between digital and analog circuitries further ensures that the audio signal is not to be contaminated.
VOLUME CONTROL (D2V ONLY) D2’s volume control is composed of a ladder of +-0.1% high precision resistors and an array of analog switches which are low in resistance, noise, and distortion. No mechanical parts are used. Frequent use does not erode its precision.
SPECIFICATIONS DAC 24-bit DAC X 2 (up to 192Ksps, 24-bit) Digital Inputs USB x 1, Asynchronous Audio Class 1.0/2.0; SPDIF x 1; TosLink x 2; AES X 1 Optical / RCA / XLR 32K / 44.1K / 48K / 64K / 88.2K / 96K / 128K /176.4K / 192K PCM 16/24 bits, and DSD64 (DoP) USB 32K / 44.1K / 48K / 64K / 88.2K / 96K / 128K / 176.4K /192K / 352.8K / 384K PCM 16/24 bits, and DSD64 / DSD128 (DoP) Digital Filter COS Proprietary; Linear Phase Delay Frequency Response + 0dB, -0.5dB / 20 Hz ~20KHz Full Scale Output 2Vrms (unbalanced), 4Vrms (balanced) Output Impedance 100 ohm THD+N < 0.001% (- 100dB) , (192Ksps, 24-bit, 20Hz ~ 20KHz, A-weighted) Signal To Noise Ratio > 110dB, (192Ksps, 24-bit, 20Hz ~ 20KHz, A-weighted) Volume (D2V only) 0.25 dB/step X 256 steps (0 ~ -63.75dB) Display 128 X 64 pixels white OLED display Weight 3.5 kg Dimension 260 mm (W) x 250 mm (D) x 60 mm (H), (Boot is not included) Power 90 ~ 240VAC Normal Operation < 15W; Standby < 0.5W

Sep 04, 23 2:54pm
Note that in HiFiShark, all sales in U.S. have been in the $3850 to $4000 range in last few years, except for the resold lesser condition/unknown use/multiple ownership powder coated black version that I sold cheap.

Includes: DAC, remote, original packaging/box, power cord