O2 Build Complete: Let the objective, subjective listening tests commence!

[JamesMcProgger]

I havent read the whole thread, someone have used the K601 with the O2? 

 

[jdkJake]

 
Quote:

WOW.  At a glance, The Wire sounds like the O2 on steroids.  (I haven't found the measurements yet, but I haven't looked hard either.)  It looks to be a bit more expensive but still very reasonable.  I'm surprised the thread has gotten so long (and gone on so long) at diyaudio without the apparent interest spilling over to this site!

http://www.head-fi.org/t/552386/the-wire-headphone-amplifier
 
 

 

[maverickronin]

Quote:

I havent read the whole thread, someone have used the K601 with the O2? 

In case you haven't seen this one already, Shike likes his O2 with the K701 and K601 (mentioned in an edit at the end of the post).

 

[JamesMcProgger]

Quote:

In case you haven't seen this one already, Shike likes his O2 with the K701 and K601 (mentioned in an edit at the end of the post).

thanks man, will read that one.
 

 

[firev1]

Quote:

WOW.  At a glance, The Wire sounds like the O2 on steroids.  (I haven't found the measurements yet, but I haven't looked hard either.)  It looks to be a bit more expensive but still very reasonable.  I'm surprised the thread has gotten so long (and gone on so long) at diyaudio without the apparent interest spilling over to this site!  When you say you're going to build yours soon, are you referring to the O2 or The Wire?

O2, I will be looking at the The Wire as well but I'm less familiar with electronics and will have to investigate the parts I have to get a bit. Seeing the B22 does not have any proper measurements done to it, I suppose in terms of amplification this will be my end-all headphone amp. 
 
EDIT: Actually I'm not really surprised that interest did not really spill over here since there was little interest in the objective approach till voldemort got kicked and drama happened.

 

[qusp]

Quote:

Owen [OCR] has done a fantastic job with The Wire, it looks good & it's measurements look very good... Think he's working on a speaker amp version at the moment, that's on top of the three headphone versions and dedicated psu already done... Got my fingers crossed that I'll be able to get a se-se kit from the current GB.
 
Back to the O2, I hope to be doing a nice brushed Aluminium & Oak enclosure for mine over the coming weekend. My first attempt went wrong, but this time I've been able to borrow the right tools for the job.
 
If I'm unlucky with The Wire kit, I'll build a second O2 for use with my Acer W500 tablet as part of a trasportable rig. I'm keeping an eye on nwavguy's blog regarding cheap dac's, but I'd like a few recommendations regarding IEM's in the <£150 bracket.
 
Paul

Paul, ive seen you post this around this forum a number of times. you will be able to get one of the kits, as it turned out Owen was able to get a good deal on getting quite a few more pcbs than he had planned to for very little more money, so there are more pcbs for all 3 versions, not just the BAL-SE version as it was thought.
 
good job that, i have the BAL-SE version from the last generation and its an utterly superb amp that deserves its reputation. also 'the wire' Class AB power amp is similar to the headphone amp by way of philosophy, extremely good measurements (sub ppm for a power amp is pretty fantastic), physical size and name only, the circuits are quite different and could not even really be called similar
 
btw Owen's nick is opc, not OCR
 
i'm also getting the BAL-BAL version of the wire to try in my portable dac (modified feedback/VAS slightly for lower input impedance) as well as adding 4 channels of the power amp to the 4 channels of discrete class A i have there already. the guy seems to have a pretty magic touch, every design he puts out seems to both sound fantastic and measure extremely well, they dont have to be mutually exclusive as many here think. IMO his designs compete with and in many cases beat most all commercial designs on the market at any price; for example his version of the D1 IV stage is superb and transformed my dac
 
theres no magic in the design though, just well thought out, well laid out, well proven designs and technique using the best parts for the job.
 

 

[Paul Blythe]

Oops, ocr - opc, my normal read it as one thing & typing it as something completely different... that's normal practice for me & I hate using the D word.
 
Yeah, probably have posted my intrest in The Wire once or twice more than what is healthy, just a touch of impatience setting in... what he's doing is quite increadable, not only the design & testing, but running the GB & forum threads also, kudos.
 
 
- Owen appeared to have been quite busy recently, so even though I new the GB was still open I wasn't sure of what was available. The se-se version I was after looked to have been a popular option early on. Just been on diyAudio and am happy that I'll be getting a se-se kit & psu kit... I can start shopping for all the other bits now  )

 

[LFF]

Quote:

 
 
Do you still have a pair of Fischer FA-002W High Editions?  You said they were extremely picky about amps, so I'm curious whether a neutral amp like the O2 works for them, or if they actually require some special kind of coloration to meet their potential.

The FA-003 and the FA-002W sound fantastic with the O2. The High Editions do not.

 

[mikeaj]

Here are some simple RMAA tests of the O2 I did, but unfortunately my sound card's line in is not really up to the task of measuring the O2.  The distortion is almost the same regardless of whether or not the O2 is loaded.  I guess that's a result in of itself.
 
http://www.head-fi.org/t/568705/review-nwavguys-o2-diy-amplifier/165#post_7906139

 

[qusp]

Quote:

Oops, ocr - opc, my normal read it as one thing & typing it as something completely different... that's normal practice for me & I hate using the D word.
 
Yeah, probably have posted my intrest in The Wire once or twice more than what is healthy, just a touch of impatience setting in... what he's doing is quite increadable, not only the design & testing, but running the GB & forum threads also, kudos.
 
 
- Owen appeared to have been quite busy recently, so even though I new the GB was still open I wasn't sure of what was available. The se-se version I was after looked to have been a popular option early on. Just been on diyAudio and am happy that I'll be getting a se-se kit & psu kit... I can start shopping for all the other bits now  )

no problem, I understand. yes hes been VERY busy lately, quite a task he took on as you mention. Glad you got on the list before it closed yesterday. anyway we'll let these guys get back on with their O2 thread, sorry for the intrusion guys.

 

[cheapskateaudio]

Quote:

Oops, ocr - opc, my normal read it as one thing & typing it as something completely different... that's normal practice for me & I hate using the D word.
 
Yeah, probably have posted my intrest in The Wire once or twice more than what is healthy, just a touch of impatience setting in... what he's doing is quite increadable, not only the design & testing, but running the GB & forum threads also, kudos.
 
 
- Owen appeared to have been quite busy recently, so even though I new the GB was still open I wasn't sure of what was available. The se-se version I was after looked to have been a popular option early on. Just been on diyAudio and am happy that I'll be getting a se-se kit & psu kit... I can start shopping for all the other bits now  )

I got in for a BAL-BAL kit & PSU, yeah baby!

 

[sphinxvc]

I just ordered one from John Saeber over at JDS Labs.  Anyone know which wall transformer I can use?  Link (Amazon or otherwise) would be most helpful -- no electrical knowledge whatsoever here.

 

[cheapskateaudio]

O2 GOLD EDITION
 
The sound:
 
In short, this version annihilates the first version.
 
That being said, I don't know what specifically made it so much better or if it's the totality of the upgrades. For the most part I just upgraded everything in the signal path. 

 
What did I do?
 
More precise resistors throughout, more precise caps, .22uf WIMA poly caps, higher precision ceramic caps throughout, 0.1% - 0.5% precision resistors throughout , high precision 170pf ceramic caps on the dominant poles of the op amps (vs 220pf).
 
The result is no smearing of the midrange, no audible clicks or thumps on power on or off, generally vastly improved sound.
 
I also used a higher spec'ed comparator and gain stage op amp.
 
Harshness is gone, HD650's sound really good, smooth, much more to expectations, HD448's sound superb also, amazingly good for $99.
 
I might post more details at some point. But I honestly think that all the "super designers" will just laugh at me as delusional, however, I know what my ears are telling me... PARTS MATTER.
 
 

 

[deadlylover]

Quote:

 
I might post more details at some point. But I honestly think that all the "super designers" will just laugh at me as delusional, however, I know what my ears are telling me... PARTS MATTER.

 
Or, the first version was dodgy, and you just fixed it.

 

[mikeaj]

Quote:

I just ordered one from John Saeber over at JDS Labs.  Anyone know which wall transformer I can use?  Link (Amazon or otherwise) would be most helpful -- no electrical knowledge whatsoever here.

Amazon may be a bit optimistic.  You're looking mostly at large electronics suppliers, which often have minimum order limits, significant shipping charges, etc.
 
You're looking for an AC/AC wall transformer with an output of around 14-20V.  Some "12V" transformers have a high enough actual level to be used.  In general, the cheapest option that works is the Triad WAU12-200, and it will be plenty except in some more fringe cases (say driving very insensitive low-impedance headphones or doing bench testing).  That's what I use for mine.
 
http://www.mouser.com/Search/ProductDetail.aspx?qs=gbLhNGEXPTb00xhB4fgq6w%3D%3D
 
Higher like WAU16-400, WAU20-200, etc. is okay.
 
 
Here is the snippet from the "place" which may not be linked:
 
"There has been some confusion over the wall transformer and it’s a critical component. Most wall transformers put out DC but the O2’s power supply requires at least 13.5 volts AC. The ideal transformer would be rated at 14 - 16 VAC and 400 mA or higher. In North America the Triad WAU12-200 from Mouser is rated at 12 volts but is really about 13.5 VAC with no load, and on normal 120 volt line voltage works fine for anything but full power sine wave testing or driving rare low impedance power hungry cans. If your line voltage is below 117 VAC  or 235 VAC, and/or you plan to drive difficult low impedance headpones (i.e. HiFiMan planars), I would suggest a 14+ VAC transformer at 400+ mA. The best Mouser transformers are the WAU16-400, 412-218054 or WAU16-1000 CUI. But those are more expensive than the WAU12-200. The WAU20-200 also works for higher impedance headphones. At least some European 230 volt input 12 VAC output transformers only measure around 11.5 to 12 volts on normal line voltage and won’t work (especially if designed for halogen lights). You can also change the power jack to a 5.5mm x 2.5mm version if needed to match the plug of different wall transformers."