[Head Injury]

Quote:

I don't have an O2 but I have looked through the web site and read much of the material.  I am mighty impressed. So even if someone finds the result not sufficiently "colorful", they should at least recognize the high quality of the engineering effort before issuing disparaging words.

But he's just throwing datasheets together 

 

[estreeter]

Quote:

I don't have an O2 but I have looked through the web site and read much of the material.  I am mighty impressed. So even if someone finds the result not sufficiently "colorful", they should at least recognize the high quality of the engineering effort before issuing disparaging words.

I agree that Voldemort has put an enormous amount of work into the O2, but I also acknowledge that many of us don't have the technical background to be able to verify all of his claims for the design. By 'many of us', I mean me. 

 
Voldemort could tell me pretty much anything and I wouldn't be able to challenge him, but that applies to every other amp builder out there.
 

 

[cheapskateaudio]

 
Quote:

 
I don't like that argument very much in general, since it sets the barrier of entry too high, and that isn't necessary to make some kind of contribution.  You can do a lot of good design work with good intuition, sound engineering principles, calculations, and some key simulations.  I just don't see any of that either from cheapskateaudio.
 
Measuring prototypes is just a part of it (and even then, for at least some kind of sanity check, a $100-200 sound card is a reasonable start).
 
 
But in this case, where somebody is making bold claims about a design being terrible, then yeah, some kind of evidence (analysis or measurements) seems appropriate.

I am not an audio engineer. However, I can read and Google.

Quote:

What's strange is that you're the only person making such a fuss over this amp, everyone else is entirely satisfied with this amp, but not you, crazy world huh ? In the first post of this thread you seem entirely satisfied with this amp, what has changed since then ? Has the amp suddenly transmuted from gold to crap ? Nightmare of the alchemists.... Maybe the stars are wrong ? What happened, really ? 

I was wrong at first, then I corrected my thinking. Again, lets not pretend this amp is something "everyone is entirely satisfied with" (BS), as if it's some sort of flawless work of art. LOL. Seriously, get out of here, there is no product on earth everyone is entirely satisfied with. 
 

 

[fubar3]

Quote:

But he's just throwing datasheets together 

Yes, but he throws them together so nicely. I am admiring the attention to detail, clear organization of material, and enormous patience. I suppose the guy must get some satisfaction from the doing since the obvious rewards don't seem worth the effort.
 

 

[estreeter]

Quote:

Yes, but he throws them together so nicely. I am admiring the attention to detail, clear organization of material, and enormous patience. I suppose the guy must get some satisfaction from the doing since the obvious rewards don't seem worth the effort.
 

From his blog, the O2 came into being after various people called him out along the lines of 'OK, hotshot, if these amps are so flawed, where is YOUR design ?'. And so it goes.

 

[bcg27]

Of course TI knows nothing about op amp circuit design 

 You make it sound like using their *ahem* reference designs is a bad thing

 

[cheapskateaudio]

 
Quote:

Of course TI knows nothing about op amp circuit design 

 You make it sound like using their *ahem* reference designs is a bad thing

It's not a bad idea to start, especially when slapping something together as part of winning a dare. 
 
A wheel is a wheel right? Cars roll the same on any round wheel. If I roll a car on a flat surface and measure the cars height with a laser to determine how perfectly it is rolling I will find that all wheels are essentially the same. But a lesser known fact about wheels is that lighter wheels allow cars to get better mileage and accelerate/decelerate faster. Yet car companies, (who know better) still put stupid heavy wheels on cars (cause they're cheap/tough and all wheels are round) but in reality there *is* a difference. So now we have a quandry wherein the wheels have been measured with lasers yet the lasers don't tell the whole truth, but how could that be, its a LASER BEAM for the love of god, LASER BEAMS do not LIE... 
 
Here's another analogy. I have a car with 3 wheels, they're all bent so the car rolls funny, I buy a nice new wheel to replace the missing fourth wheel, I get in my car and... it still rolls funny, darn that new rounder wheel did nothing. Ok, maybe it's my inner ear that is deceiving me so lets get the laser, nope, laser says the car still rolls funny, darn, new wheel does nothing, I guess all wheels are wobbly, or, the better wheel doesn't change how the whole car performs, or, I need a new car not better wheels.
 
 
 
 
 
 
 
 

 

[Shamharoth]

Quote:

I was wrong at first, then I corrected my thinking. Again, lets not pretend this amp is something "everyone is entirely satisfied with" (BS), as if it's some sort of flawless work of art. LOL. Seriously, get out of here, there is no product on earth everyone is entirely satisfied with. 
 

Well, show me the people who think this amp is a heap of crap. There must be some, but they're not the majority.
 

Quote:

 

It's not a bad idea to start, especially when slapping something together as part of winning a dare. 
 
A wheel is a wheel right? Cars roll the same on any round wheel. If I roll a car on a flat surface and measure the cars height with a laser to determine how perfectly it is rolling I will find that all wheels are essentially the same. But a lesser known fact about wheels is that lighter wheels allow cars to get better mileage and accelerate/decelerate faster. Yet car companies, (who know better) still put stupid heavy wheels on cars (cause they're cheap/tough and all wheels are round) but in reality there *is* a difference. So now we have a quandry wherein the wheels have been measured with lasers yet the lasers don't tell the whole truth, but how could that be, its a LASER BEAM for the love of god, LASER BEAMS do not LIE... 
 
 

 
Yet an heavy wheel can also act as a flywheel, thus saving energy and incidentally making the car slightly more efficient. And that's funny because you're the one who says your ears are more accurate than the lasers (the d-Scope)... You're really using the wrong argument here... But obviously, a $10k piece of equipment must be wrong... As we all are... Please, enlighten us, master. We beg you.
 
 

Here's another analogy. I have a car with 3 wheels, they're all bent so the car rolls funny, I buy a nice new wheel to replace the missing fourth wheel, I get in my car and... it still rolls funny, darn that new rounder wheel did nothing. Ok, maybe it's my inner ear that is deceiving me so lets get the laser, nope, laser says the car still rolls funny, darn, new wheel does nothing, I guess all wheels are wobbly, or, the better wheel doesn't change how the whole car performs, or, I need a new car not better wheels.
 

That's funny because that's exactly the opposite of what you did, you took a car with straight wheels and added oddly shaped ones to supposedly "improve the design". 

 
 
The thing is, you can always say what you want, but that means NOTHING until you PROVE IT

 

[TheShaman]

Anyone had a chance to compare O2 to The Wire?

 

[i_djoel2000]

Quote:

Anyone had a chance to compare O2 to The Wire?

i believe someone should compare this to burson instead, since the designer believes this amp will blow any branded amp within 1000 bucks range. haha
 
still waiting for a proper review of this amp, though. so far none has come

 

[qusp]

Quote:

i believe someone should compare this to burson instead, since the designer believes this amp will blow any branded amp within 1000 bucks range. haha
 
still waiting for a proper review of this amp, though. so far none has come

on the other hand i would put the wire against amps in that range in a moment. i'lll eventually build up my O2 pcbs, but i'm giving the amps away as gifts.
 
i actually dont see the burson doing that well on paper and i didnt really like the discrete opamps or regulators (all sold now after trying a few places) and this is basically all the burson is, a few of the opamps and regulators on a single pcb. certainly there is something to be said for them being put together and tuned to suit, but going on past experience the wire blows them out of the water.
 
also, i think people who built this are deceiving themselves into thinking they have built an Audi R8 for the cost of a Honda; he never designed it to be perfect, perfect it is not. he designed it to perform very well given the price and not commit any atrocities. he only claims that you should not be able to tell the difference with your ears, blind. this does not make it a reference design, reference designs are made to completely remove any error regardless of cost (within reason). that was not part of the brief; dont fool yourself it was done as an act of philanthropy, as mentioned it was a matter of ego. dont get me wrong, hes gone to a lot of trouble (with the help of a few dedicated helpers) to produce a well documented, well tested design; regardless of motive some kudos is due
 
i dont think the challenge would still stand if it were a task of finding flaws with measurement equipment. which btw has been accepted, opc has offered to build up one of his amps and exchange it with a built up O2, that should be quite interesting =)

 

[upstateguy]

Quote:

on the other hand i would put the wire against amps in that range in a moment. i'lll eventually build up my O2 pcbs, but i'm giving the amps away as gifts.
 
i actually dont see the burson doing that well on paper and i didnt really like the discrete opamps or regulators (all sold now after trying a few places) and this is basically all the burson is, a few of the opamps and regulators on a single pcb. certainly there is something to be said for them being put together and tuned to suit, but going on past experience the wire blows them out of the water.
 
also, i think people who built this are deceiving themselves into thinking they have built an Audi R8 for the cost of a Honda; he never designed it to be perfect, perfect it is not. he designed it to perform very well given the price and not commit any atrocities. he only claims that you should not be able to tell the difference with your ears, blind. this does not make it a reference design, reference designs are made to completely remove any error regardless of cost (within reason). that was not part of the brief; dont fool yourself it was done as an act of philanthropy, as mentioned it was a matter of ego. dont get me wrong, hes gone to a lot of trouble (with the help of a few dedicated helpers) to produce a well documented, well tested design; regardless of motive some kudos is due
 
i dont think the challenge would still stand if it were a task of finding flaws with measurement equipment. which btw has been accepted, opc has offered to build up one of his amps and exchange it with a built up O2, that should be quite interesting =)

+1
 
It might also be noted again, that the O2 was designed not only to be inexpensive but also very easy to build, with no surface mount components.  In that regard, the wire is a much more difficult build for a novice.
 
 
 

 

[Willakan]

Wait, if a reference design sounds the same, blind, as a cheaper design, what exactly is the point of the reference design? Better amps are all well and good, but I don't have the money to lavish on things that sound the same under blind conditions and would question the plausibility of taking as fact that those who do enjoy a superior experience.
Just to prevent any conclusion, I absolutely agree that it is possible to beat the O2 measurably by a pretty large margin, but would question the value of doing so if all you want is a transparent amplifier.
Also, how on God's earth is cheapskate still posting?

 

[mikeaj]

Quote:

 
also, i think people who built this are deceiving themselves into thinking they have built an Audi R8 for the cost of a Honda; he never designed it to be perfect, perfect it is not. he designed it to perform very well given the price and not commit any atrocities. he only claims that you should not be able to tell the difference with your ears, blind.

(emphasis added)
 
But this is a very powerful claim already.  Supposing that this is true, at least for the vast majority of listeners (I'd lump myself here of course), then there doesn't seem to be much motivation to seek anything better if your goal is to listen to music and not to acquire hardware to do effects processing or intentional coloration.  I can certainly understand auxiliary motivations of wanting the best and so on, but humor me please.  Automobile drivers can presumably tell the difference between a particular Honda and Audi just from the handling and so on, but if we're already talking about amp performance past the point where people can't tell, then that metaphor doesn't apply to this situation.
 
edit: though one flaw I can hear on the O2 is channel balance at very low volumes with sensitive IEMs, even on 1x gain and with a source that's just 1.1V.  A potentiometer's a potentiometer after all.
 
 
Out of curiosity, checking The Wire (SE-SE; not sure if this is the most relevant or "fair" comparison) and O2 specs as given, and trying to eyeball the charts on the O2, and taking these at face value...
 
Noise:
The Wire -- -116.1 dBV (A-weighted or not?)
O2 -- -114.7 dBV (A-weighted, on AC power)
 
THD+N @ 1 V:
The Wire -- 0.00030% (50 ohms)
O2 -- 0.00068% (80 ohms) and 0.0012% (32 ohms)
 
IMD (SMPTE) @ 1V:
The Wire -- intermod products around 7 kHz are -120 dB or less (50 ohms)
O2 -- intermod products around 7 kHz are -113 dB or less (150 ohms), -104 dB or less (15 ohms)
 
The Wire also maintains the performance levels a little better when moving on up to 7.2V output, compared to the O2 at about 6V output (but O2 still below 0.002% THD into 80 ohms at that level) where the knee is around 6.7V at 0.003% at 80 ohms.

 

[DRUB]

Quote:

(emphasis added)
 
But this is a very powerful claim already.  Supposing that this is true, at least for the vast majority of listeners (I'd lump myself here of course), then there doesn't seem to be much motivation to seek anything better if your goal is to listen to music and not to acquire hardware to do effects processing or intentional coloration.  I can certainly understand auxiliary motivations of wanting the best and so on, but humor me please.  Automobile drivers can presumably tell the difference between a particular Honda and Audi just from the handling and so on, but if we're already talking about amp performance past the point where people can't tell, then that metaphor doesn't apply to this situation.
 
edit: though one flaw I can hear on the O2 is channel balance at very low volumes with sensitive IEMs, even on 1x gain and with a source that's just 1.1V.  A potentiometer's a potentiometer after all.
 
 
Out of curiosity, checking The Wire (SE-SE; not sure if this is the most relevant or "fair" comparison) and O2 specs as given, and trying to eyeball the charts on the O2, and taking these at face value...
 
Noise:
The Wire -- -116.1 dBV (A-weighted or not?)
O2 -- -114.7 dBV (A-weighted, on AC power)
 
THD+N @ 1 V:
The Wire -- 0.00030% (50 ohms)
O2 -- 0.00068% (80 ohms) and 0.0012% (32 ohms)
 
IMD (SMPTE) @ 1V:
The Wire -- intermod products around 7 kHz are -120 dB or less (50 ohms)
O2 -- intermod products around 7 kHz are -113 dB or less (150 ohms), -104 dB or less (15 ohms)
 
The Wire also maintains the performance levels a little better when moving on up to 7.2V output, compared to the O2 at about 6V output (but O2 still below 0.002% THD into 80 ohms at that level) where the knee is around 6.7V at 0.003% at 80 ohms.

Thanks for the well-put measurement comparison - those differences don't seem to be in the audible realm to me, as the headphones or speakers are going to be exponentially greater in their THD, for example.