The Well-Tempered Computer, an introduction to computer audio

Tuesday, July 5, 2011

Music Software and Operating Systems

Dynobot has written a hands-on comparison of various operating system in running a computer-as-source music system.  Good read.

Monday, July 4, 2011

EAR Yoshino DAC

Tim de Paravicini is a legend.  His EAR-Yoshino phono preamps and amps are among the few analog products that has been elevated to cult classic status.  Now Tim has debuted his EAR-Yoshino DAC (est. £4000), which offers 24/192kHz capabilites and USB input. With the EAR DAC Tim de Paravicini has applied his world renown knowledge and attention to detail in the analog world to the digital domain.  

The DAC boasts a digital to analog converter with low jitter clock and enhanced operation. The DAC accepts up to 24/192 digital input from USB, coaxial SPDIF and Toslink SPDIF inputs. Immediately upon returning to the analog domain, the audio signal is passed to EAR's propreitary analog filter. The audio is output from a transformer-coupled ECC88 tube line output stage as in EAR pro audio equipment. This allows true floating balanced output as well as identical quality unbalanced line out by RCA connectors. The maximum output is 5 volt, which means it can drive directly any power amplifier of any type, with analog volume control that can be controlled by remote handset. This claims accurate, clean smooth sound, yet detailed, open and dynamic, lacking the overly-crisp, a musicality of many highly-regarded digital to analog converters. Avaialble in chrome or black aluminium finish

  • DAC chip: 24 BIT Multilevel Delta Sigma Conversion.
  • 1 x USB Interface
  • 2 x 75 Ohms Coaxial S/PDIF
  • 1 x Toslink Optical S/PDIF
  • RCA 5V rms single ended
  • Balanced XLR; 5V rms XLR pin 2 positive
  • Valve Compliment: 2x ECC88 / 6DJ8
  • Output Impedance: < 60 Ohms (balanced or single ended)
  • Recommended Load: > 600 Ohms (balanced or single ended)
  • Harmonic Distortion: < 1%
  • Frequency Response: 20Hz – 20KHz
  • Dimensions: W 435mm, D 320mm, H 95mm

Saturday, July 2, 2011

Accuphase 900 series digital components

Accuphase of Japan just launched the new DD-900 SACD transport and DC-901 DAC.  

In addition to coaxial SPDIF output, the DD-900 SACD Transport will be to output DSD stream via its proprietary HS-Link connection to the DC-901 DAC.  

The DAC sports HS-Link, coaxial, Toslink and AES/EBU inputs as well as a high speed 24/192kHz capable USB input.  It also has a "digital tape loop" I/O after the de-jitter circuit and just before the DAC chip itself for connection to a digital signal processor.  The DC-901 uses two ESS SABRE32 DAC chips, one per channel.  Volume controlled in the digital domain.  Balanced and unbalanced outputs.

Pricing approximately US$10,000 for each unit.

Friday, July 1, 2011

ToneAudio issue 38 is out

Tone Audio issue 38 is out and ready for download (PDF). Enjoy.

Schitt Audio Bifrost DAC with asynchronous USB

Schitt Audio, maker of the popular Vahalla and Lyre tube headphone amps, is now taking pre-orders for its debut stand-alone DAC to be called the Bifrost, the company's first in a planned series of three.  The DAC has a very respectable set of specs and very likable price of $349.  Featuring a 32-bit D/A conversion, fully discrete analog section, sophisticated clock management system, asynchronous USB 2.0 option, as well as SPDIF coaxial and optical inputs, all with 24/192 capability.  The DAC comes with a 5-year warranty and a 15-day satisfaction guarantee return policy. The Bifrost begins shiipping end of August 2011.

Fully Upgradable
Bifrost's modular design uses separate, snap-in USB Input and DAC/Analog cards. When USB technology changes, you can simply drop in a new, better USB Input Card. When meaningful upgrades to D/A converters come out, you can snap in a new DAC/Analog Card.

AKM4399 D/A Converter and Discrete Analog Section
AKM4399 "Super DAC" 32 bit D/A converter is used and its analog section is a fully discrete, low noise JFET design—the only op-amp in the box is a DC servo.

Advanced Bitperfect Clock Management
Bifrost dispenses with the sample rate converter and uses a sophisticated master clock management system to deliver bit-perfect data to the DAC, preserving all the original music samples--whether it's 16/44.1 or 24/192.

Asynchronous USB 2.0, 24/192, 
Featuring a high-speed USB 2.0 interface and asynchronous data transfer to 24/192, based on the C-Media CM6631 USB receiver. No drivers are required for Macs, and Windows drivers will be downloadable from this site for Windows 7, Vista, and XP.  Please note that this is a $100 option.


  • Inputs: Coaxial SPDIF, Optical SPDIF, USB (optional)
  • Input Capability: up to 24/192 for all inputs
  • Input Receiver, SPDIF: Crystal Semiconductor CS8416
  • Input Receiver, USB: C-Media CM6631
  • D/A Conversion IC: AKM4399
  • Analog Summing, Filtering: Fully Discrete, DC Coupled
  • Output: Dual RCA (single-ended)
  • Output Impedance: 75 ohms
  • Frequency Response, Analog Summing Stage: 2Hz-100KHz, -1dB (actual frequency response limited by sample rate)
  • Maximum Output: 2.2VRMS
  • THD: Less than 0.001%, 20Hz-20KHz
  • S/N: Greater than 108dB
  • Power supply: 5 stages of regulation, including separate supplies for critical digital and analog sections.
  • Upgradability: Separate, modular USB Input Card and DAC/Analog Card are snap-in replaceable.
  • Power Consumption: 15W
  • Size: 9 x 6.75 x 2.25”
  • Weight: 5 lbs