Dual USB DAC Orpheus

After long, research, experiments and auditions ,we designed this DAC which compiles all audiophile requirements. This Dac consists two separate sections realized with two separate dac chips. The digital coax section works only in PCM mode, receiving standard digital signals from CD transports or digital sources with SPDIF outputs. The input receiver is realized with low jitter chip from Wolfsen WM 8805. This receiver can accept PCM data with 24bit/192kHz resolution reclocking converted I2S information. The SPDIF section is powered with low noises LDO stabilizers from Analog Devices. The converted SPDF data accepts from Akashi Kasei flagship chip. The USB part is designed with XMOS asynchronous converter from USB to I2S and DSD native. The data from XMOS passes to another DAC chip which accept 32bit/192kHz data and direct DSD bitstream. This USB section is assembled into a separate PCB. In USB mode you can use 3 digital filters. All function modules are powered with separate ultra low noises LDO stabilizers. The analog section is realized with handmade output transformers from permalloy core for best bass sound. The transformers are connected in differential mode without signal ground. The commutation between USB and SPDF is carried out by means of analogue relays with gold contacts. They switch analog outputs without losses. We prefer to don’t commutation the digital inputs in digital parts and analog section. If we use standard PLD matrix for digital switch we will increase the digital noises and jitters to input data. We use pure silver wire in signal paths and OFC wire in power supply. The DAC is powered with one battery 12V/3,4Ah Yuasa for best sound. If the customer prefers to listen pure audiophile sound just removes automatic charger of the rear panel. The battery allows listen sound 12 hours without charge. The analog output connectors are from Cardas and Neutrik. The input connectors for digital data are from WBT and Neutrik.

The output transformers

Our company use high quality transformers in all DAC products. In this DAC we use high quality audio isolation transformer with import nickel content as 80%. The permalloy material is wound and the permalloy material is whitish, shiny, and reflective at one glance. The high purity oxygen free copper enameled wire is layered and wound and the nylon framework is made of high purity oxygen free copper enameled wire. The AC noise interference caused by the equipment can be filtered out. It has a good isolation effect.

The connectors

For analog outputs we recommended RCA connectors from Cardas. The unbalanced audio sockets are very important for sound quality. We choose Cardas GRFA S Short RCA, Rhodium over Silver plate

SPDIF connector is from WBT modelWBT-0210Cu Topline Nextgen Nextgen™ RCA socket Signature with signal conductor made of pure copper, for chassis mounting.75-ohm characteristic impedance means that these sockets not only transmit superb analogue signals but also outstanding digital audio and video signals. The transmission bandwidth is 1 GHz.
The contact elements of the connector are made of high-purity copper, one of the best electrical conductors, in order to ensure optimum signal transmission. The metal is gold-plated (nickel-free) so that the surface does not oxidise and impair contact quality.
The inner contact is an active spring contact. The newly developed three-segment tulip contact is pressed onto the central pin of the RCA plug by a surrounding double bronze spring ring. Not only does this ensure reliable contact with non-standardised RCA plugs but contact also remains reliable even after the plug has been connected and disconnected many times over.The outer contact is in the shape of a double wave which encompasses the socket element made of robust Ultramid*. This wave shape guarantees reliable contact with any RCA plug. In addition, the reduction in the amount of conductor material to the absolute minimum prevents the creation of eddy currents, enabling the WBT-0210 to transmit signals that are totally free of distortion.Eddy currents occur in metal components near to which alternating current flows. These currents can result in major signal distortions.



Technical data:

• Frequency response: +/- 0.25 dB; 10Hz-100 kHz
• Distortion at 50 Hz (Source 40 ohms): 0.05% at +20 dBu
• Output level: 2,1V (RCA) / 4,2V(XLR)
• Audio formats I2S mode:Wav, Flac, MP3.
• Audio formats DSD mode: DFF, DSF.
• Digital format USB mode: I2S 32bit/192kHz (PCM), DSD.
• Digital format SPDIF mode: I2S 24bit/192kHz
• Analog outputs: 1RCA; 1XLR
• Digital inputs: 1 RCA SPDIF; 1AES/EBU; 1 USB B asynchronous 32bit / 384kHz
• Phase shift: under 2 degrees
• Dimensions: Dac box:450mm X 280mm X 80mm
• Warranty:5years

© Ratzov Tsenkov - Audio Design