The all new RT Audio Design DAC is an improved version of Hi-res USB DAC Orpheus with more expensive components and connectors. “When the audiophile chose a digital source, is guided by the sound quality and the price/quality ratio. We have designed DAC with the best sound characteristics at an optimal price.”
USB section
For USB to I2S conversion, we use an XMOS processor in combination with the 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 a separate PCB and consists of a S/PDIF low jitter receiver receiving digital data from coaxial and AES/EBU inputs. The PCB is specially designed with maximal short signal pats, without crossing of the digital and analog data stream. The second section is the 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 of low manufacture tolerance. In the 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 are 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 filters, we use output transformers for best sounds and low tolerance resistors as passive I/V convertors. In this DAC we have chosen a high-quality audio transformer Lundahl LL1545A ratio 1:4 with perfect frequency response and low THD.
The power supply unit
High-quality power is very important for digital devices because every power noise give a 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 a separate power supply unit. In this charger, we used analog low noise stabilized power supply. The power transformer is low noise and the rectifier is realized with SiC Schottky diodes “king of rectifier diodes”. This diode doesn’t have a reverse current which made charging of filter capacitors very fast without loss. One charge cycle allows 4 hours of audiophile listening without the use of a power supply unit.
Wiring and connectors
Every audiophile knows that cables and connectors influence 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 perfectly 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 the treble is clean. This DAC is perfect for jazz lovers and hard rock fans.
Technical data
- Frequency response: 10Hz – 70 kHz
- Audio formats: PCM( FLAC ,WAV, APE,MP3)
- Resolution: PCM 24bit/192kHz
- Phase shift: under 2 degrees
- THD: 0,02%
- Output level : 2,1Vp-p unbalanced
- Digital inputs: 1 USB ,1 Coax,1 AES/EBU
- Analog outputs:2 RCA