First of all,thanks fellow forumers RangerRed and aasing for bringing Nwavguy's O2 Headamp to Lowyat.net

O2: High Performance Portable/Home Amp, by NwAvGuy

[WTA] O2 desktop/portable headphone amp, Objective 2 headphone amp (Amplifiers)

Lots of information are available at Nwavguy's blog,and it's worthy to give a try,as decent headamps around us are not cheap anyway

O2 Headphone Amp

O2 Design Process

O2 Details

O2 Summary





ODAC click here

This post has been edited by Leolabs: Aug 26 2012, 07:07 PM

A finished O2 by me:



Some features (Contents taken from Nwavguys's blog):

-Works well with nearly all headphones from 16 – 600 ohms

-Front panel switchable gain for best headphone & source compatibility

-High Output: 7 Volts RMS & 200+ mA peak current

-Current limiting to help protect low impedance headphones from damage

-Unique battery rundown protection prevents battery & headphone damage

-No volume control “rustling” (unwanted noise when changing volume settings)

-Optimal star ground and true split bipolar power supply (NO ground splitter)

-Multi-stage design with local feedback improves noise, distortion and stability

-Individual output stages for each channel improves performance

-RF and DC input protection, brief short circuit output protection

-Fast: Slew Rate 3+ times faster than worst case requirement & bandwidth>250 kHz

-Compensated for maximum stability and optimized transient response

This post has been edited by Leolabs: Jan 21 2012, 08:46 PM

I am quite interested in this amp, but probably going to buy a completed amp instead of building one for myself.

Measurements (by Nwavguy using Prism Sound dScope Series III,rich guy ):

-Frequency Response: +/- 0.1 dB
-THD 1 kHz 150 Ohms: 0.0016%
-THD 1 kHz 15 Ohms: 0.0023%
-THD 20 Hz 15 Ohms: 0.0023%
-THD 20 kHz 15 Ohms: 0.010%
-IMD CCIF 15 Ohms: 0.001%
-IMD SMPTE: 0.002%
-Noise (ref 400 mV): -105 dB
-Max Output 15 Ohms: 337 mW
-Max Output 33 Ohms: 613 mW
-Max Output 150 Ohms: 355 mW
-Output Impedance: 0.54 Ohms
-Crosstalk 15 Ohms: 65 dB
-Channel Balance: 0.6 dB

This post has been edited by Leolabs: Oct 30 2011, 09:25 PM

The DIY info of O2:









This post has been edited by Leolabs: Apr 21 2012, 11:59 AM

you can buy the pcb only from jds labs, no need to GB anymore: http://www.jdslabs.com/item.php?fetchitem=O2PCB

I already got the PCBs,almost same price per unit,but lower shipping cost (if by Pos Laju)

you use local pcb manufacturer? nicee..

Complete amp is under planning,as the enclosure recommended by Nwavguy is not cheap in Malaysia ,naked amp is easier

---

Added on October 30, 2011, 11:06 pmNope,if using local PCB manufacturer,the NRE (set-up) cost is already over RM200,and individual PCB cost is around RM10,UNLESS order is over a few hundred units,otherwise per PCB cost is high to me.

Those blank PCBs are "Chinese Airborne Unit" ,u get the meaning...



This post has been edited by Leolabs: Nov 11 2011, 11:27 AM

For those who can't wait for a complete and cheaper version by me ,can try out JDS Labs O2 Assembled PCB

JDS LABS:Objective2 Assembled PCB



Cost around RM300 plus shipping,WITHOUT enclosure & AC adapter

I just ordered the PCB from Leolabs, hope can get the amp done in this month. Thanks for all

Keep us posted, with pictures wui!

And here we have,some O2s :

Very nice!

Guys,I need reviewers,those who are around/stay at Penang State and interested,please let me know....thx

So how is the progress now? What is the pricing if get from you? Plan to do a review of my own especially with some current hungry headphone. (not ortho, just dynamic driver that drain current)

This post has been edited by Akuma no Hana: Dec 14 2011, 02:01 AM

As u can see,5 units finished,just waiting for the arrival of casing,next month probably...

Actually I already got my own review,but to be fair and square,need to ask others to review for me...

Reality is,if u are using a 600 ohms headphone with O2,powered it by AC adapter...

But if u not using those high ohms stuff,then powered it by batteries,sure catch your ears...

Sorry i don't catch the part. Care to explain abit.

think he means:

if you are using 600ohms headphone, use the O2 amp with an AC adapter.

if not, then use it with batteries and the amp is sure to fascinate you.

i'm interested to review this, but i'm in johor

got pimeta to compare this amp to