Objective2 Headphone Amplifier
The Objective2 (O2) is an open source headphone amplifier designed by NwAvGuy, with emphasis on benchmark performance and low cost. This item includes a fully assembled and hand tested O2 amplifier, ready for use. You will only need an AC adapter suitable for your region.
The O2 has created a stir in Head-Fi.orgís do-it-yourself community. After being banned from Head-Fi for heated discussion, he proceeded to design O2 for maximum benchmark performance to prove his points. Itís large and heavy, so hardly worth consideration as a portable amp, however, O2 lives up to its name.
For more information on the O2, please refer to NwAvGuy's O2 Details article.
Our Objective2's are assembled 100% in accordance with NwAvGuy's default, high-performance specifications.
Reference Grade Sound
Objective2 achieves vanishingly low THD and noise performance for audible perfection.
Low Output Impedance
O2's extremely low output impedance ensures transparent frequency response for all headphone loads.
At over 600mW, Objective2 provides enough output power to drive all dynamic headphones on the market with authority.
|Frequency Response||+/-0.01 dB (20Hz-20kHz)|
|THD 1 Khz 150 Ohms||0.0016%|
|IMD CCIF 15 Ohms||0.001%|
|Noise (ref 400 mV)||-105 dB|
|Max Output (33 Ohms)||613 mW|
|Max Output (150 Ohms)||355 mW|
|Max Output (600 Ohms)||88 mW|
|Output Impedance||0.54 ohms|
|Crosstalk (15 ohms)||-65 dB|
|Channel Balance (50% volume)||0.6 dB|
|Battery Run Time||6-8 Hours|
|Gain||2.5x and 6.5x|
|Volume Potentiometer Taper||Alps 15A or 3B|
|Batteries||2x9V LSD NiMH|
|Power||Battery or 14-20VAC|
|Case Dimensions (mm)||108.50 x 80.00 x 29.50|
|Case Dimensions (in)||4.27 x 3.15 x 1.16|
- Fully Assembled O2 Headphone Amplifier
- 2x Tenergy 9V NiMH, Low-Self-Discharge Batteries
- Free Set of Rubber Feet
- Instructions Guide
O2 requires an AC adapter to charge its batteries.. Power adapters are sold separately, as we ship worldwide. Be sure to select one of the following:
- North America: Triad AC Adapter
- Europe, Australia, Great Britain, Singapore: GEZ AC Adapter
- Other: Please refer to our O2 Power Adapter Guide
Default gain levels of Objective2 are intended to work well with over 95% of headphones on the market. We use the stock O2 with headphones as low as 16 ohms @ 1 dB/mW, and as high as 600 ohms (very high and very low efficiency, respectively). There is no reason to alter stock gain unless you regularly listen at extremely low volumes. We can set custom gain of 1.0/2.5x upon request, or you can easily perform this change by removing two resistors.
Default gain levels of Objective2 are intended to work well with over 95% of headphones on the market. We use the stock O2 with headphones as low as 16 ohms @ 1 dB/mW, and as high as 600 ohms (very high and very low efficiency, respectively).
There is no reason to change the stock gain unless you regularly listen at extremely low volumes. Gain can easily be changed by removing two resistors.
We can set gain of 1.0x/6.5x or 2.5x/1.0x upon request. Other combinations are also possible, but may delay shipment by 1-3 business days. Simply make your special request(s) during checkout.