[PelPix]

An honest amplifier introduces nothing.  It is the mastering engineer's job to add life to music, not the end-user.  Nothing will sound good on this amp because everything that has ever been recorded in the history of ever has been mixed and mastered with the expectation that the end-user will color it.

 

[Maxvla]

So to all you in the know, should I be waiting for a desktop O2 or a 'The Wire'? Any ideas of costs of both in assembled retail form?

 

[Forte]

Quote:

I wish people would stop pretending this amp is some kind of reference design. I saw the O2's gain stage in a PDF for a TI opamp. It's a cool little amp to build and have a blast with but it's far from being a big time performer. In fact, the O2's performance makes me think someone cobbled together circuits from a variety of pdf's, measured them with a scope they probably bought at a flea market, and decided to "turn the audio world on end" with this new fangled concept of measuring things.
 
Don't get me wrong, I like the amp, I just think it's absurd how this amp has been placed on a pedestal, and I'll admit I was one of the people who initially was ready to call into question everyone else, but the fact is it's this amp that is wrong, not the rest of the world.
 
 

 
 

    
Apart from the Flea Market quip that post sums up this whole O2 stunt perfectly.  
 

 
 

 

[Shamharoth]

Quote:

I wish people would stop pretending this amp is some kind of reference design. I saw the O2's gain stage in a PDF for a TI opamp. It's a cool little amp to build and have a blast with but it's far from being a big time performer. In fact, the O2's performance makes me think someone cobbled together circuits from a variety of pdf's, measured them with a scope they probably bought at a flea market, and decided to "turn the audio world on end" with this new fangled concept of measuring things.
 
Don't get me wrong, I like the amp, I just think it's absurd how this amp has been placed on a pedestal, and I'll admit I was one of the people who initially was ready to call into question everyone else, but the fact is it's this amp that is wrong, not the rest of the world.
 
 

You sure know better.
 

 

[SobbingWallet]

Quote:

but the fact is it's this amp that is wrong, not the rest of the world.  
 

 
The fact is, facts are different from subjective opinions, and they require hard, verifiable evidence to substantiate them.

 
 

 

[Paul Blythe]

Unsure on the overall costings for both. The Wire has limited availability as the current GB has ended, but I'm working on a costing of roughly £150 - £200 for a fully built SE-SE version. The ODA won't be around until next year, nwavguy should be posting an initial update with details somtime in December. The perfomance shouldn't be any different to the O2, just a few updates to various parts due to current component costs or tweeks. The ODA should also have the option of a DAC daughter board. I'd imagine the main ODA wont cost any more than the O2, then the dac's cost on top of that.
 
Compairing posted measurements from both, The Wire out performs O2.
 
Paul
 
Quote:

So to all you in the know, should I be waiting for a desktop O2 or a 'The Wire'? Any ideas of costs of both in assembled retail form?

 

 

[Head Injury]

Quote:

I wish people would stop pretending this amp is some kind of reference design. I saw the O2's gain stage in a PDF for a TI opamp. It's a cool little amp to build and have a blast with but it's far from being a big time performer. In fact, the O2's performance makes me think someone cobbled together circuits from a variety of pdf's, measured them with a scope they probably bought at a flea market, and decided to "turn the audio world on end" with this new fangled concept of measuring things.
 
Don't get me wrong, I like the amp, I just think it's absurd how this amp has been placed on a pedestal, and I'll admit I was one of the people who initially was ready to call into question everyone else, but the fact is it's this amp that is wrong, not the rest of the world.

Great! Now quit making things up and address my post.

 

[mikeaj]

Hey guys, once I saw a design for a wheel.  It was like circular.  No high-performance car should ever use circular wheels.  (On a serious note, this is maybe a different usage of the word "reference" but overall, the typical application designs on data sheets are there as a reference for good reason.)
 
 
Anyhow, The Wire--and probably some others--offers higher performance if you're looking for that, which I think everybody agrees with including Voldemort.  O2's goal is lowest cost for high performance (while being portable and not destroying your headphones if a battery gets disconnected or something like that), not highest performance.  If you're including the DAC option cost in the ODA, that's not a fair comparison in cost to The Wire unless I'm misunderstanding what goes in some of the kits.  AFAIK the base config doesn't even have a volume control.  Wires don't have volume control after all.
 
If somebody, DIY design or commercial, could offer something with O2 or better performance and some combination of (1) lower cost, (2) smaller size, (3) more features, I'd be all for that, and so would most people.

 

[Willakan]

My God.
Cheapskate, what you have come out with is prettymuch the perfect example of slanderous BS. In fact, what you have come out with quite simply shows astounding ignorance on your part on and on the part of everyone who agreed with you. It does however nicely demonstrate the utter delusion of the hard-core "audio is magic" crowd, who promptly leap out of the woodwork to congratulate you. If your crap doesn't get deleted, whilst my thread gets locked, apparently partially for daring to suggest that an amplifier that has never been measured is not a paragon of objective virtue... Reported anyhow. We shall see.
 
Meanwhile, let me put it to you straight:
 
Your modifications are a load of a baloney. The mere idea of you improving on an amp optimised with thousands of dollars of instrumentation - with all the design choices documented for all to see - is quite frankly farcical. Suggesting that you have transformed the sound simply demonstrates astounding degrees of ignorance and arrogance. You don't have the faintest idea what you're doing and are far too egotistical to ever entertain the prospect of unavoidable bias or that you broke the amplifier with your "improvements." As for your attempts to "prove" it with microphone testing, when you invent such a test rig that can measure tiny amounts of distortion with reproducible accuracy, please let me know.
 
Your "NwAvGuy made crap up off a datasheet" comment beggars belief. Seriously, are you incapable of reading? Have you seen the number of opamps and the like tested for this amplifier? Have you seen the number of prototypes done? This would be insulting to any designer, let alone someone who has gone to great lengths to publically document everything. I honestly cannot understand why you would come out with the total crap that you have. It is provably wrong on every point.
 
So far, all you've managed to do is throw slanderous BS around and laughably claim to have beaten careful engineering, backed up by maths and science, with your "improvements". Grow up.
 

 

[mikeaj]

No, some of the mods are probably legitimate improvements (maybe side-grades depending on your perspective), depending on which part was chosen.  Lower-noise resistors isn't going to hurt anything, and those with lower tolerance range isn't going to hurt the channel balance either.  Better capacitors here and there may make an improvement as well, though in some cases, substituting for a higher value is probably worse.  Some of these improvements may be so small as to be not even measurable with high end gear, but still.  e.g. noise floor is not dominated by the properties of the default resistors in the signal paths, unless at very high gain settings.
 
Changing the op amps is a different matter.
 
It's not like the designer tested for every combination of everything possible, just generally not the stuff that is going to make an insignificant difference for performance.  In terms of the power circuitry (there's a BOM revision involving resistor changes coming up to address hysteresis with the battery charging circuit actually), and handling turn off/on transients possibly, I wouldn't be too surprised at some easy improvements being possible.
 
 
 
As for signal path mods to improve performance in audible ways as was claimed, that's what I have a hard time with as well.  When suggesting the implausible, it's best to go with more evidence than one person's sighted listening tests, if possible.

 

[Shamharoth]

Quote:

No, some of the mods are probably legitimate improvements (maybe side-grades depending on your perspective), depending on which part was chosen.  Lower-noise resistors isn't going to hurt anything, and those with lower tolerance range isn't going to hurt the channel balance either.  Better capacitors here and there may make an improvement as well, though in some cases, substituting for a higher value is probably worse.  Some of these improvements may be so small as to be not even measurable with high end gear, but still.  e.g. noise floor is not dominated by the properties of the default resistors in the signal paths, unless at very high gain settings.
 
Changing the op amps is a different matter.
 
It's not like the designer tested for every combination of everything possible, just generally not the stuff that is going to make an insignificant difference for performance.  In terms of the power circuitry (there's a BOM revision involving resistor changes coming up to address hysteresis with the battery charging circuit actually), and handling turn off/on transients possibly, I wouldn't be too surprised at some easy improvements being possible.
 
 
 
As for signal path mods to improve performance in audible ways as was claimed, that's what I have a hard time with as well.  When suggesting the implausible, it's best to go with more evidence than one person's sighted listening tests, if possible.

Exactly. This isn't a secret. Lord Voldemort always said he chose the cheapest components to get the job done without degrading the performance. The thing cheapskateaudio doesn't seem to understand is that the O2 was never advertised as "the best amp ever". It was advertised as the best bang for the buck. And it totally is. I dare him to come with a cheaper alternative that performs as well. And if he can, well, that's great for everyone.
 

 

[samsquanch]

Quote:

...the O2 was never advertised as "the best amp ever". 

 
"THE (nearly) PERFECT HEADPHONE AMP"
 
what would be better than perfect?
 
I just wanted to point that out...  to be a jerk.

 

[Willakan]

A lot of these improvements (ultra-low noise resistors, potential change from better caps) have been tested by NwAvGuy. Better resistors does sod all. Ditto for caps, by virtue of the results of analysing the currents across them.
Anyhow, that still doesn't affect the fact that any audible differences are either from breaking the amp with the modifications, or from involuntary bias.

 

[Shamharoth]

Quote:

 
"THE (nearly) PERFECT HEADPHONE AMP"
 
what would be better than perfect?
 
I just wanted to point that out...  to be a jerk.

The keyword here is "nearly".
The thing is that there will never be a "perfect" amp. You can make an amp more perfect than the previous, sure. But you have to think about :
- what will it cost ?
- is it improved audibly ?
- in short: is it worth it ?
 
There are amps superior to the O2 out there, but they cost more and the difference isn't really huge. They are better though. But the reason why people buy the O2 isn't to have the best overkill amp out there. It's buying a good amp at an incredibly low price. And the O2 does just that. But it isn't a "one-size-fits-all" kind of amp, and there are people (like our friend cheapskateaudio) that will prefer more colored amps, or simply people who would like an amp that measure even better. But in all cases, what matters is which amp you like the most. 
 
The problem with cheapskateaudio claims isn't that they are substantially wrong. It's that he claims they are improvements when all he has done, really, is adapt the amp to his taste. And that's good for him. But that's a little presomptuous to claim that he improved the design and that the vanilla amp is crap.

 

[samsquanch]

Quote:

A lot of these improvements (ultra-low noise resistors, potential change from better caps) have been tested by NwAvGuy. Better resistors does sod all. Ditto for caps, by virtue of the results of analysing the currents across them.
That still does affect that any audible differences are either from breaking the amp with the modifications, or from involuntary bias.

I would ask you to post a link to him saying that but.... so may I ask for a quoted snippet stating this?
 
 
My issue with this statement (or at least how I'm reading it) is that it states that audio quality will remain constant as long as current across a component remains constant.  2mA of a pure sine wave is not the same as 2mA of sine wave plus harmonics and or distortion, audibly speaking that is.