[Xenophon]

  the vali has ringing problem now. many people can't stay with it.

Never heard the Vali but if this is true then it's simply an atrocious design error and I'd never purchase anything  from that manufacturer.

 

[adydula]

Never had a vali, had a Lyr, never had any hum, well built performed well but not anywhere near transparent etc...that said lots of people love it.
 
Ah the wonderful world of tubes, hot, glowing, humming, lots of distortion but very nostalgic!
 
Wonder what exactly you would like to DIY or Mod to the ODAC to make it "better"??
 
A.

 

[Xenophon]

  Never had a vali, had a Lyr, never had any hum, well built performed well but not anywhere near transparent etc...that said lots of people love it.
 
Ah the wonderful world of tubes, hot, glowing, humming, lots of distortion but very nostalgic!
 
Wonder what exactly you would like to DIY or Mod to the ODAC to make it "better"??
 
A.

 
Don't know if that part was directed at me or someone else but if at me:  I wouldn't do a thing.  The design is what it is and if I'd want to upgrade the wiser course would imo simply be to purchase another amp rather than sinking a proportionately high amount into the O2.  
 
BTW, I also like tubes.  As you say, they come with their warts but the subjective experience also counts.  Last time I put in a new driver tube I was stuck with horrible micro phonics...2 days of suffering before the person quietened down.

 

[lokesen]

  Objective2 Amplifier + ODAC Illustrated Write-up
 
http://diy.koenigs.dk/2014/02/21/o2odac-amplifier-and-dac/
 

 

 
 

Added a few sections to the write-up. Cheers.

 

[MrMateoHead]

  Its a simple design, but the wonder is what the designer went thru and did to make it as good as it is....."is the rest of the story".
 
Taking the time to do layouts, over and over and over just to get the measurements as best possible....
 
Trying to match reference circuit measurements or best them...this is wonderful engineering...and we all benefit!!
 
Ah....such a great time to be in audio!!
 
A.

Any company (or in this case, person) worth their salt would spend the time to "develop" a design until it meets or exceeds its design criteria. It is not all signal to noise, either. A good amp should have power! Lots of it. It sets up the ability to drive anything, and provide ample headroom for HDR recordings (like classical which I am increasingly getting more into).
 
Maybe the O2 is what happens when engineers, instead of marketers, are 'driving' product development.
 
A big piece of the story missing over at Toms was a measure of the power output! Specifically, we have no idea how strong the amps were other than given an ability (or not), to drive a high-impedance load. The headphones they used were quite efficient. But for what it is worth, apparently the listeners could not reliably detect what should have been dismal output impedance / sloppy bass of the 889. More discernible was the -1.4dB response at 100 hz.

 

[r010159]

 
Any company (or in this case, person) worth their salt would spend the time to "develop" a design until it meets or exceeds its design criteria. It is not all signal to noise, either. A good amp should have power! Lots of it. It sets up the ability to drive anything, and provide ample headroom for HDR recordings (like classical which I am increasingly getting more into).
 
Maybe the O2 is what happens when engineers, instead of marketers, are 'driving' product development.
 
A big piece of the story missing over at Toms was a measure of the power output! Specifically, we have no idea how strong the amps were other than given an ability (or not), to drive a high-impedance load. The headphones they used were quite efficient. But for what it is worth, apparently the listeners could not reliably detect what should have been dismal output impedance / sloppy bass of the 889. More discernible was the -1.4dB response at 100 hz.

 
I do believe you are correct. The focus of the O2 project was what can be accomplished by the design of the product, not marketing concerns, or sloppy engineering. As far as Toms goes, I do see the listeners as being experienced. But there is a difference between an experienced ear and a well-trained and experienced ear. So to me, as a measured interpretation of the results, this means the discerning average listener will not be able to reliably tell the difference. But an experienced audiophile probably can.
 
Bob Graham

 

[headwhacker]

the O2 was designed with considerations and compromises so that it can drive 90+ % of headphone out there. From highly sensitive iems to full size cans.
 
Looking pretty, and unnecessary features are very low to non-existent in the list of design goals.

 

[MrMateoHead]

   
I do believe you are correct. The focus of the O2 project was what can be accomplished by the design of the product, not marketing concerns, or sloppy engineering. As far as Toms goes, I do see the listeners as being experienced. But there is a difference between an experienced ear and a well-trained and experienced ear. So to me, as a measured interpretation of the results, this means the discerning average listener will not be able to reliably tell the difference. But an experienced audiophile probably can.
 
Bob Graham

What is an average listener? What is an Audiophile?
 
One listener in the test used $3K worth of gear - including Senn 800s and an Asus Xonar that were the same as in the test. The other person used 86K (Euro, so about $129,000) worth of gear! The rich person also used Senn 800s. Both were at an advantage, in the sense that they were familiar with some of the test gear.
 
I highly doubt the former or latter would identify as "average" listeners. As audiophiles, they failed to reliably detect the amps through Senn 800s which are nothing if not unforgiving. So, essentially, the test, if you believe its results, rules out the possibility that anyone could tell a difference in a blind test. I doubt that will change their audio budgets, but certainly it rules out amplifiers as a major differentiating factor (at least among HQ properly designed amps that aren't trying to have a sonic signature).
 
Now, I use ~$700 worth of gear on headphones, and ~$450 for the 2.1 setup. I've got maybe $600 in my car. Or in other words, I have no listening setup that I currently listen to that I've spent more than $1,000 on. I think I get a very high quality listening experience and can hear "crap" much more easily than most. But I could not, through any speaker you gave me, tell the difference between source-matched and volume-matched amplifiers that I rely on.
 
Of course, given performance and features that I might want (bridgeability, high power, etc), I wouldn't stick with a realtek chipset when an O2 is available for a mere 50X more!

 

[r010159]

  What is an average listener? What is an Audiophile?
 
One listener in the test used $3K worth of gear - including Senn 800s and an Asus Xonar that were the same as in the test. The other person used 86K (Euro, so about $129,000) worth of gear! The rich person also used Senn 800s. Both were at an advantage, in the sense that they were familiar with some of the test gear.
 
[snip]

 
I missed that. They are definitely not your average listener, more like audiophiles to have purchased that expensive equipment. What I meant by audiophile is a well-trained ear that comes with experience.
 
Bob Graham

 

[JacobLee89]

 
 
Quote:

  Well if you find sonic benefits let me know as I might want you to do it to my ODAC. I'm not diy savvy myself

I have definitely misread that. The doodlebug is not a direct modification of the ODAC, but is a standalone USB isolator which includes its own power regulator.
 
On other news, I have finally acquired and built my own booster board for the O2 amp.
Because I haven't quite grasped the terminology in describing sound I'll try to keep this as simple as possible:
 
With my HD650s (currently only headphones), the change was definitely noticeable: small details I previously had to concentrate on became sharper, bass gained a bit more "thump", and I am sure I had some "out of headphone" experiences with some of my tracks (i.e: Sileypud from Ultrasone's 2006 Test Demo CD).
 
I wouldn't say it changed the sound signature at all, but rather widened its dynamics "on top of" O2s neutral sound.
 
Definitely worth the money and effort. Thumbs up to adgr!

 

[mcandmar]

Originally Posted by JacobLee89 /img/forum/go_quote.gif
 
With my HD650s (currently only headphones), the change was definitely noticeable: small details I previously had to concentrate on became sharper, bass gained a bit more "thump", and I am sure I had some "out of headphone" experiences with some of my tracks (i.e: Sileypud from Ultrasone's 2006 Test Demo CD).
 
I wouldn't say it changed the sound signature at all, but rather widened its dynamics "on top of" O2s neutral sound.
 
Definitely worth the money and effort. Thumbs up to adgr!

 
I can 2nd that, its pretty much what i experienced too. I built mine using the optional OPA827 opamps. Overall i found better clarity and detail, and as above more energy in the mid / low end. It puts a bit of life back into the music basically.
 
I've attached a pic for those who are wondering what were talking about. Highly recommended.
 

 

[AsianBatman]

Is that an ODAC PCB on top?

 

[JacobLee89]

  Is that an ODAC PCB on top?

The T shaped Blue PCB is the Booster board modification.

 

[Xenophon]

  I have definitely misread that. The doodlebug is not a direct modification of the ODAC, but is a standalone USB isolator which includes its own power regulator.
 
On other news, I have finally acquired and built my own booster board for the O2 amp.
Because I haven't quite grasped the terminology in describing sound I'll try to keep this as simple as possible:
 
With my HD650s (currently only headphones), the change was definitely noticeable: small details I previously had to concentrate on became sharper, bass gained a bit more "thump", and I am sure I had some "out of headphone" experiences with some of my tracks (i.e: Sileypud from Ultrasone's 2006 Test Demo CD).
 
I wouldn't say it changed the sound signature at all, but rather widened its dynamics "on top of" O2s neutral sound.
 
Definitely worth the money and effort. Thumbs up to adgr!

Thanks!  Although I personally won't upgrade mine -for reasons already mentioned- that's good to know and I salute adgr for his engineering, the effort he put into this and for the results!

 

[JacobLee89]

  Thanks!  Although I personally won't upgrade mine -for reasons already mentioned- that's good to know and I salute adgr for his engineering, the effort he put into this and for the results!

 
The only way to make it a huge hit for a decent price, would be to DIY the O2 as well, which can squeeze the budget into under $190 for the entire setup, of course that doesn't include the wall wart and soldering gear.
 
My real reasoning is that I'd wanted an upgrade that didn't require me to spend a non existant $700, which of course would be the BH Crack with various options chosen. Though right now with the booster board I feel ample satisfied for now.