The Objective2 (O2) Headphone Amp DIY Project

[ethanolson]

7.2V pack is more common than 8.4V... but not at all for 9V/PP3 battery layouts.

I think everyone knew that.

Anyway, so what's killing off the batteries in the O2 faster than expected? What would the effect be of having added resistence in the battery circuit, in theory AND in practice?

[jmwreck]

hello guys, I wanted to ask about this transformer: http://www.evernote.com/shard/s102/s...12874e98482e60

this is the one I have, if I assemble it, can I use it to power and charge my o2 ?

my concern is that I havent read VAC on the output

thanks

[coolhead]

I got a problem here. After I forgot to turn off it for over 24hr, it is heavily distord now. has anyone face this problem before? What you think is spoiled?
Thanks.
-coolhead

[greenalien]

Further to Lorriman's heads up on the Superlux HD681 headphones, mine have now arrived - extraordinarily good value for money, comfortable to wear and excellent sound quality. Check out the discussion here Rock Grotto Audio Forum - For Headphones - Headphone Amps - Amplifiers - X-Can V2 - Musical Fidelity - headphone Discussion - Amplifier Discussion - DIY - Amplifier Kits - Projects - SCHA - Sennheiser - Beyer - Grado - Audio Technica - Headphone amp
- they definitely sound smoother after being in use for a few hours. A very good companion to the O2.

[MrSlim]

Originally Posted by coolhead

I got a problem here. After I forgot to turn off it for over 24hr, it is heavily distord now. has anyone face this problem before? What you think is spoiled?
Thanks.
-coolhead

Describe what it sounds like if you can, one or both channels, was it plugged into AC or on battery, etc...

[Willakan]

Over at Head-Fi the O2 review thread is really rather fun. Out of all the impressions from reasonably respected people with very high post-counts:

1) A couple of people declared it a wonderous wire with gain.
2) A few were more conservative and declared it "almost" up there with (INSERT EXPENSIVE AMP HERE)
3) A few more declared that was silly and the O2 wasn't even in the same league.
4) Another respected individual has just popped up and declared it is coloured and beaten by a CMOY modified to use opamps paralleled in the output stage.

Funny how nobody can agree on what the amp sounds like when the sound to be expected has not been suggested in advance!

[ethanolson]

Head-Fi just stripped my signature by themselves and shot me a PM about it. My blog link was not acceptable so I turned my back on my Head-Fi affiliation and, after some thought, wiped out my blog as well since it wasn't turning out like I had hoped. It's funny how quickly things can change, yet how little impact it really has on life.

[MrSlim]

Originally Posted by ethanolson

Head-Fi just stripped my signature by themselves and shot me a PM about it. My blog link was not acceptable so I turned my back on my Head-Fi affiliation and, after some thought, wiped out my blog as well since it wasn't turning out like I had hoped. It's funny how quickly things can change, yet how little impact it really has on life.

What was their issue?

[qusp]

Originally Posted by Willakan

Funny how nobody can agree on what the amp sounds like when the sound to be expected has not been suggested in advance!

well tbh as much as i dont always agree with what happens over there, using the fact nobody can agree on what something sounds like is hardly a valid criticism. people often dont agree about things that are very black and white, right the way to how good eggs taste. so expecting a consensus on sound is a bit ridiculous IMO considering we all have a different idea of what neutral is, well worse than that neutral/flat ear response IS different for everyone, forget it when you throw in different source, different headphones, different music, different taste, different experience, different language, different vocabulary, different mood. so its a bit of a cheap shot IMO.

[ethanolson]

@MrSlim, they didn't like that my signature linked to my former blog, which had reviews of audio equipment and steps I've taken to improve the sound. My latest article discussed the need or lack of a need for a headphone amp and got technical about it to prove that sometimes (because of headphone efficiency) the only thing a well designed amp, like the O2, actually does is fight distortion and improve damping... neither of which are amplification, but compensate for poor design. Many of that I've learned here following the O2 thread and at the nwavguy.com blog.

I don't think Jude took the time to read my blog, but he may have scanned some of it. He stripped my signature completely and CC'd joe and currawong.