ODAC ( Objective DAC ) What is it:

The ODAC, a UAC1 DAC, is a co-design between Yoyodyne Consulting and audio blogger NwAvGuy. The ODAC adheres to the principle of measurable performance (objective) versus subjective performance (marketing and personal bias). All claims made about the ODAC are supported by repeatable testing procedures.

The ODAC is a daughter card that will mount in the ODA with a 4-pin header and mounting hardware. The ODAC may also be retrofitted internally to an O2 headphone amplifier when the rechargable batteries are removed. A 4-40 3/8" screw and 2 nuts will physicially secure the ODAC to the O2 board. 3 wires must be soldered between the ODAC and the O2 to connect the LINE-OUT of the ODAC to the input of the O2 input.

Alternately, the ODAC can be mounted in a small custom enclosure and used as a standalone DAC with the O2 or any amplifier that has a 2vrms LINE-IN port. You may mount a 3.5mm connector (footprint on the board) or take the LINE-OUT to a pair of panel mounted RCA connectors.

The card is built around the Tenor TE7022L UAC1 engine and the ESS Technology ES9023 24 bit DAC. The ODAC is powered from the USB bus with a low noise, filtered power supply.


Visit NwAvGuy's blog for a full technical analysis of the ODAC
  • Frequency Response: +/- 0.1 dB (10 hz - 19 Khz 24/44)
  • THD+N 100 hz 0 dBFS: 0.0029%
  • THD+N 20 hz -1 dBFS: 0.003%
  • THD+N 10 Khz -1 dBFS: 0.003%
  • IMD CCIF 19/20 Khz -3 dBFS: 0.0011%
  • IMD SMPTE -1 dBFS: 0.0004%
  • Noise A-Weighted dBu 24/44: --102.8 dBu
  • Dynamic Range: > 111 dB A-Weighted
  • Linearity Error -90 dBFS 24/44: 0.0 dB
  • Crosstalk 0 dBFS Line Out 100K: --93.5 dB
  • USB Jitter 11025 hz J-test 24/44: Excellent
  • Maximum Output Line Out 100K: 2.0 Vrms
  • Distortion: < 0.005%
  • PCB Dimensions: 49.0 x 58.0 mm

Prices and Ordering:

The ODAC was "Designed and Assembled in the USA" and is available now. ODAC boards and enclosures can be purchased from

Please contact me directly if you wish a large OEM quantity purchase for your local market. George.Boudreau@YoyodyneConsulting.ca


The ODAC UAC1 engine, the TE7022L, is covered by an NDA and datasheets are not available to the public. Even with this limitation there is interest in the ODAC schematic. Premission has been obtained from GFEC and I have made the ODAC schematic available. You may download the ODAC schematic from here

ODAC pcb

Production ODAC with the optional 3.5mm connector installed