COS Engineering D2 Dac



” A simple to use, high quality DAC – just connect, sit back and enjoy”

SKU COS_D2 Category

COS Engineerings’ D2 is built to turn digital data into real music. It is a half size component armed with the company’s proprietary algorithm.

The D2 is virtually plug and play with USB, Toslink (x2), SPDIF and AES/EBU inputs and once connected there are just two options to select and then the D2 does the rest, so you can sit back and enjoy.

The music presentation from the D2 offers a fine acoustic aura, with a pitch-dark backdrop and expansive soundstage.

The D2 comes in two versions, DAC only, and as the D2V with an analogue volume control to connect directly to a power amplifier.

An OLED screen, which displays input source, buffer, and volume (D2V), provides instant information.

The built-in processing created by the COS algorithm is the secret behind the D2’s exceptionally good sound.


  • 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 significant computation is handled by a powerful DSP capable of 3648 MMAC (millions multiply Accumulate Operations) per second.
  • Fully Balanced Design:
    • Balanced design is applied throughout the entire audio signal path. Even-order harmonics on the differential signal pairs are carefully matched and thus effectively cancelled in order to achieve the lowest possible distortions.
  • Galvanic Isolation:
    • The galvanic isolation between digital and analogue circuits further ensures that the audio signal is not contaminated.
  • Buffer & Re-clocking:
    • The D2 receives data from digital sources whether a streamer, a PC, a CD transport, or a mobile device, aligns them in exact frames with a one-second buffer (on/off option), and sends them out for interpretation by the COS algorithm.
    • The processed data is then converted to analogue signals, under the coordination of a crystal oscillator with a jitter precision less than 1ps and dedicated re-clocking circuitry.
  • Volume Control (D2V only):
    • D2’s volume control is composed of a ladder with +/-0.1% high precision resistors and an array of analogue switches which are low in resistance, noise and distortion.
    • No mechanical parts are used and frequent use does not erode its precision.
  • Power:
    • The D2 harnesses two selected switching mode power supplies with specially designed circuitry for lower noise.
    • The power supply works with 100-240VAC so there is no need to select voltage.


  • DAC:
    • Digital input: USB x1 Asynchronous 1.0/2.0 (selectable); Toslink x2; SPDIF x1; AES/EBU x1.
    • Sampling rate: Optical/RCA/XLR up to 192K PCM 24 bit; USB 1.0 up to 96K PCM 24 bit; USB 2.0 up to 192K PCM 24 bit & DSD64/128 (DoP)
    • Digital-to-Analogue converter: 24 bit DAC x2 (up to 192K 24 bit)
    • Digital filter: COS Proprietary, linear phase delay
  • Volume (D2V only):
    • Steps: 0.25dB/step x 256 steps (0 – 63.75dB)
    • Total range: 64dB
    • Accuracy: within +/- 0.1dB
  • Analogue ouput:
    • Frequency response: + 0dB, – 0.5dB (20Hz – 20 KHz)
    • THD+N: <0.001% (-100dB) 192K, 24 bit, 20Hz – 20KHz, A weighted.
    • Signal-to-Noise ratio: >110dB 192K, 24 bit, 20Hz – 20KHz, A weighted.
    • Full scale output: Unbalanced 2V rms; Balanced 4V rms
    • Output impedance: 100 ohm
  • General:
    • Display: 128 x 64 pixels white OLED
    • Weight: 3.5 Kg
    • Dimensions (mm): 260 (W) x 250 (D) x 60 (H) not including footers
    • Power: 100-240 VAC
    • Normal operation: < 15W; standby 0.5W (typical)
    • Finish: silver or black anodised aluminium