Orpheus mk III

The Orpheus mk III is a DAC module designed around the well regarded Wolfson WM8740 chip. It is a differential voltage output DAC The WM8740(WM8741) is a very high performance stereo DAC designed for audio applications such as CD, DVD, home theatre systems, set top boxes and digital TV. The WM8740 supports data input word lengths from 16 to 24-bits and sampling rates up to 192kHz. The WM8740 consists of a serial interface port, digital interpolation filter, multi-bit sigma delta modulator and stereo DAC in a small 28-pin SSOP package. The WM8740 also includes a digitally controllable mute and attenuator function on each channel.The internal digital filter has two selectable roll-off characteristics. A sharp or slow roll-off can be selected dependent on application requirements. Additionally, the internal digital filter can be by-passed and the WM8740 used with an external digital filter. Separate analog and digital power sections feature National Semiconductor low-drop out (LDO) regulators. Power supply electrolytic capacitors are Panasonic and Nichicon. All resistors are  0,1% thin film. The output stages are realized through transformers Sowter 323 or Sowter3575 in differential mode for minimal harmonic distortion and best frequency response. We use digital input SPDIF transformer, which equals the impedance of the two sources(CD Transport output and  Dac input).

Battery Power supply unit

We use separate battery power supply with Valve Regulated Lead Acid Battery 12V/1,3Ah and automatic charge system. This allows reducing the noises from power supply. The sound is very clean with wide stage.


Technical data

Frequency response- 10Hz- 30kHz

120dB SNR (’A’ weighted, mono @ 48kHz)

117dB SNR (’A’ weighted, stereo @ 48kHz)

104dB THD (’A’ weighted @ 48kHz)

Sampling frequency : 8kHz – 192kHz

Input data word : 16 to 24-bit

Selectable digital low pass filter

Output level- 2Vpp

Output impedance-47kohm

Phase shift- <2degr

Digital input – SPDIF

Resolution- 24bit/192khz I2S format

Dimension; Dac case 160mmx72mmx220mm   , Power case       160mmx72mmx220mm

Optional – luxury wooden case + engraving brass


© Ratzov Tsenkov - Audio Design