The O2 (Objective2) Headphone Amplifier is the first design of the US blogger and electrical engineer NwAvGuy which is produced under the Common Creative License
This outstanding performance has now been paired with the ObjectiveDAC (ODAC), the latest design of NwAvGuy, a truly transparent 24bit DAC produced by Yoyodyne Consulting
Technical Specifications:
- 3.5mm Input and Output Connector
- build in ODAC with mini USB connector
- ALPS Stereo Potentiometer
- 230V~ 15 VAC 500mA Power supply (Euro, UK, AU and US supplies available)
- Gain switch (2.5x and 6.5x gain as standard)
- Size 108.5 x 84 x 30 mm (without Knobs and screws)
- Black or Silver case
The gain settings will accommodate a wide range of Headphones from 16 Ohms to 250 Ohms (this should cover 95% of on the market available headphones). Should you want to use headphones that are more or less effective, gain settings can be amended to 1x, 2x, 3x, 4x, 5x, 6x, 7x, 8.5x, 10x and 12x. Please choose Non Standard from the Gain Options and specify your desired gain settings in the comments field underneath it.
An USB cable (1m) with ferrite bead is included.
*Images show front and back of the same device!
Measurements ObjectiveDAC:
| Frequency Response 10Hz - 19KHz 24/44 | +/- 0.1 dB |
| Noise A-Weighted dBu 22/44 | -102 dBu |
| Dynamic Range -60 dBFS A-Wtd | -111.1 dBu |
| USB Jitter 11025Hz J-Test 24/44 | -106.5 dB |
Measurements O2:
| Frequency Response | +/- 0.1 dB |
| Noise (ref 400 mV) | -105 dB |
| THD 1 Khz 150 Ohms | 0.0016% |
| Output Impedance | 0.54 Ohms |
A full list of the measurements can be found in NwAvGuy's blog.



