Hi- Res USB DAC Orpheus SE



This DAC is improved version of Hi- res USB DAC Orpheus with more expensive components and connectors. When the audiophile chose digital source, is guided by the sound quality and the price / quality ratio. We have designed DAC with the best sound characteristics with optimal price.

USB section
For usb to I2S conversion we use XMOS processor in combination with galvanic barrier. This section is powered with low noise separate power supply. The USB converter uses reclock to reduce jitter significantly.I2S, S/PDIF outputs ,oscillators and reclock are galvanically isolated from Xmos and Usb ground(outputs, two oscillators and reclock, done by Xilinx CPLD are after the isolator). The galvanic eliminates common noise originated by the computer.

DAC Section
The DAC section is realized on separate PCB and consists S/PDIF low jitter receiver receiving digital data from coaxial and AES/EBU inputs. The PCB is special designed with maximal short signal pats, without crossing of digital and analog data steam. The second section is DAC chip realized with the flagship Burr-Broun current output digital converter. The DAC is configurated to works in differential output mode.All components are low manufacture tolerance. In DAC section we use ultra low noise stabilizers reducing digital noises and hums.



Analog stage
The analog stage is very important for quality sound If the analog filter and I/V converter is designed incorrect the sound will be with timing and phase delays. Our philosophy is: no active LPF filters and buffers, no active I/V converter .As analog filter we use output transformers for best sounds and low tolerance resistors as passive I/V convertor .In this DAC we have choose high quality audio transformer Lundahl LL1545A ratio 1:4 with perfect frequency response and low THD.


The power supply unit
The high quality power is very important for digital devises, because every power noise give negative effect on the quality of digital data. The Hi – res USB DAC is powered with one 12V/2,2 Ah battery .For charging we used separate power supply unit. In this charger we used analog low noise stabilized power supply. The power transformer is low noise and rectifier is realized with SiC Schottky diodes “king of rectifier diodes”. This diodes doesn’t have reverse current which made charging of filter capacitors very fast without lost. One charge cycle allows 4 hours of audiophile listening without the use of power supply unit.

IMG_6808 copy IMG_6776a copy


Wiring and connectors
Every audiophile knows that cables and connectors influence on the sound quality. We choose Cardas cables and RCA connectors in analog outputs .For coaxial digital input we use WBT, Neutrik for AES/EBU and USB digital input.

The Sound
This DAC plays perfect all PCM audio files .The sound stage is large and deep with perfect focus in every detail.The bass is very fast, deep and punchable and trebles are clean. This DAC is perfect for jazz lovers and hard rock fans.

Technical data

Frequency response: 10 Hz – 70 kHz
Audio formats: PCM (FLAC, WAV, APE, MP3)
Resolution: PCM 24bit/192kHz
Phase shift: < 2 degrees
THD: 0,02 %
Output level : 2,1 Vp-p unbalanced
Digital inputs: 1 USB, 1 Coax, 1 AES/EBU
Analog outputs:2 RCA

© Ratzov Tsenkov - Audio Design