Objective2 (O2) amp

[Tyll Hertsens]

I've had my fill of trying to show people how to properly do things to be honest. On top of that I don't relish the thought of dealing with somebody as disturbed as this. Then we have the whole issue of why I should help somebody who is clearly going to start selling amps commercially.

From what I can tell, this is not true.

Not defending him, just my observation.

[spritzer]

I've have heard enough rumors to the contrary to take them seriously but only time will tell I guess.

[Tyll Hertsens]

I've have heard enough rumors to the contrary to take them seriously but only time will tell I guess.

How many sources have talked to him?

[spritzer]

Not sure but I for one wouldn't believe anything he says. Maybe it is just me though...

[dsavitsk]

I've have heard enough rumors to the contrary to take them seriously but only time will tell I guess.

A. Who cares, B. The only such rumors I have seen have been from you, and C. The ground plane on the PCB is indeed a little messy, and there appear to be traces to nowhere. However, it seems really unlikely that any of that will actually influence performance negatively. Perhaps it reflects badly on the designer as someone who is not particularly detail oriented, but all empirical evidence seems to indicate that the amplifier operates as advertised.

Edited October 6, 2011 by dsavitsk

[grawk]

as advertised being its the greatest headphone amp ever?

[CherryBomb]

This is what the guy advertised:

"The Objective₂ (O2) is my attempt at a “One-Size-Fits-Nearly-All” headphone amp. It can drive most any headphone from the most sensitive IEMs to some really power hungry full size cans from 16 to 600 ohms. It’s small, inexpensive, and runs on batteries or AC power."

[spritzer]

A. Who cares, B. The only such rumors I have seen have been from you, and C. The ground plane on the PCB is indeed a little messy, and there appear to be traces to nowhere. However, it seems really unlikely that any of that will actually influence performance negatively. Perhaps it reflects badly on the designer as someone who is not particularly detail oriented, but all empirical evidence seems to indicate that the amplifier operates as advertised.

I don't care about this amp one bit but plenty of people do and some of them happen to be Mafia members.

As for the PCB design, you clearly don't see my point. This idiot attacks Ti openly and claims to have a superior design (because nobody has ever designed for low distortion before ) but can't even do the basics right . The end result leaves a lot to be desired and the only reason this gets any attention is due to people out to prove a point they don't even understand.

[fishski13]

i'm building one for a friend that's down on his luck, having to sell off most of his headphone gears. i don't think that saying it's indistinguishable from the BM DAC1 is a great compliment either - i own one.

what the 'objectivity as religion' types don't understand is that expectation bias cuts both ways.

Edited October 7, 2011 by fishski13

[limp]

Not sure but I for one wouldn't believe anything he says. Maybe it is just me though...

If he's planning to make money from it, why would he let Epiphany Acoustics build and sell for profit, or indeed release it under a cc by-nd license?

[Dreadhead]

i'm building one for a friend that's down on his luck, having to sell off most of his headphone gears. i don't think that saying it's indistinguishable from the BM DAC1 is a great compliment either - i own one.

what the 'objectivity as religion' types don't understand is that expectation bias cuts both ways.

Not with double blind testing it doesn't

[fishski13]

Not with double blind testing it doesn't

if you don't think you'll hear a difference, you probably won't. if you think you'll hear a difference, you probably will. both are biases. a DBT will sort out the latter, but not the former.

[Dreadhead]

if you don't think you'll hear a difference, you probably won't. if you think you'll hear a difference, you probably will. both are biases. a DBT will sort out the latter, but not the former.

While true it's not a problem if you do it with people who are convinced there's a difference which is the majority in this hobby.

To be clear too I think about 80% of the time I've done blind testing there has been an audible difference (though I recently redid one that I used to get 95% chance I was not gessing and I couldn't tell the difference so there's also a "training" bias).

Also it's common to have you DBT designed so there is a statistically noticable difference in some of the samples being compared to at least illuminate that bias.

Edited October 7, 2011 by Dreadhead

[fishski13]

While true it's not a problem if you do it with people who are convinced there's a difference which is the majority in this hobby.

To be clear too I think about 80% of the time I've done blind testing there has been an audible difference (though I recently redid one that I used to get 95% chance I was not gessing and I couldn't tell the difference so there's also a "training" bias).

Also it's common to have you DBT designed so there is a statistically noticable difference in some of the samples being compared to at least illuminate that bias.

agreed. with the only DBT i've conducted, comparing 3 different cables i built with grossly different geometries and wire, i had to "train"/practice hard and select particular songs prior to the actual test to score 29/30. DBTing amps would be a bitch.

[Pars]

I'm not a statistician (or even really know much about it and DBTs), but I would think that DBTing amps would be a piece of cake compared to cables, unless some of the cables had R/C/L added to them (something like MIT boxes) to purposefully skew them from a piece of wire. Perhaps that is what you meant by grossly different geometries and wire.

[fishski13]

I'm not a statistician (or even really know much about it and DBTs), but I would think that DBTing amps would be a piece of cake compared to cables, unless some of the cables had R/C/L added to them (something like MIT boxes) to purposefully skew them from a piece of wire. Perhaps that is what you meant by grossly different geometries and wire.

i wasn't clear - i'm referring to the actual process of carrying out a DBT. i agree, amps would be much easier than wire to parse sonic differences. i would personally have a hard time evaluating an amp without being able to play with the volume. kind of like evaluating the road handle of car while riding shotgun (sorry for yet another banal car analogy in an audio discussion). having someone volume match each amp would be tricky and add another variable for error. i think DBTs would be more accurate if they more closely replicated the actual experience.

Edited October 7, 2011 by fishski13

[dsavitsk]

I don't care about this amp one bit

You seem to, which is fine. But, to be clear, what you seem to care about is the commercialization of the amp, not "about it." I don't know if you care about it, and I don't care whether you do. I don't actually care if you care about commercialization either, other than to say I am confused about the whole thing.

As for the PCB design, you clearly don't see my point.

Apparently not. But, you have not posted anything I have seen to illuminate your point.

This idiot

I am not going to debate the designer's disposition.

attacks Ti openly and claims to have a superior design (because nobody has ever designed for low distortion before )

My understanding is that he claimed that a certain amp did not meet its published specs. Seems like a fair thing to post, and not an attack. I don't actually know if it does or not, but that is the sort of thing that can be settled reasonably easily.

but can't even do the basics right .

What basics are wrong. He designed an amp that meets its specs. The PCB may be sloppy, but it seems to be good enough for what it needs to do. What else do you not like?

The end result leaves a lot to be desired and the only reason this gets any attention is due to people out to prove a point they don't even understand.

Not sure whom this is a swipe at. But, as I say, I just want to know what the actual objections are.

Anyhow, this is like movie censors that drive up audiences by being outraged. If people had just ignored this guy, there would not be hundreds of these in the works.

Edited October 7, 2011 by dsavitsk

[spritzer]

...other than to say I am confused about the whole thing.

That certainly appears to be the case, you certainly don't see the whole picture here.

[ujamerstand]

My understanding is that he claimed that a certain amp did not meet its published specs. Seems like a fair thing to post, and not an attack. I don't actually know if it does or not, but that is the sort of thing that can be settled reasonably easily.

What I saw was that nwavguy published an article that suggested the specs published on amb's website was wrong. Ti did not appreciate the fact that the guy did not attempt to contact him to sort out the problem before posting the article, and since nwavguy's mini3 was a nonstandard build, he suggests there might have been something wrong with the build, causing the bad measurements. This turns into an argument, communication breaks down, and nwavguy goes on to smear Ti whenever he could. :s

I see all of this as a loose loose situation, Ti's reputation gets damaged, people started fighting among each other about who's right and who's wrong. What could have been solved discretely instead overblown into a nasty situation. His articles really did more damage to the community than it helped.

The O2 does seem that it meets its specs. But its designer could loose some of that sense of self-righteousness.

[Pars]

Here are some jpgs from his posted gerbers. Sorry, my graphics capability here kinda sucks

Really odd ground plane layout, including a couple of traces that don't go anywhere (connected to a pair of series caps).

Edited October 7, 2011 by Pars

[Pars]

The dual FETs I've used (and tested, at least for Idss) aren't matched all that well oftentimes. I can get much better matches using singles. Thermally coupling them can be an issue (hence the heatsinks sold on a GB here awhile ago). FETs include 2SJ109, 2SK389 (and their singles, 2SJ74 and 2SK170).

I posted this on the diyaudio forum thread. So far, Qusp has agreed with me. No response from TC (as Al termed him).

This kind of illustrates the bravado employed as modus operandi, in that he states "well known facts" as such, and no one calls him on it. In this case, it seems apparent that he has never used the dual devices, and just makes assumptions based upon theory, not reality. Maybe at one time the known quality of dual devices was true, but not from my experience, at least for what I measured for.

Edited October 9, 2011 by Pars

[luvdunhill]

Then there is evidence that matching doesn't even matter, take Hannes (h_a at DiyA) often disregarded tests using an AP. I'd expect him to take this route in fact, but again he is simply unaware of anything but his own observations and assumptions.

[limp]

I posted this on the diyaudio forum thread. So far, Qusp has agreed with me. No response from TC (as Al termed him).

This kind of illustrates the bravado employed as modus operandi, in that he states "well known facts" as such, and no one calls him on it. In this case, it seems apparent that he has never used the dual devices, and just makes assumptions based upon theory, not reality. Maybe at one time the known quality of dual devices was true, but not from my experience, at least for what I measured for.

Isn't the question more wether two randomly chosen singles will match better than one randomly chosen double, as most people building this amplifier won't be interested in the added effort of matching devices?

[Dreadhead]

Isn't the question more wether two randomly chosen singles will match better than one randomly chosen double, as most people building this amplifier won't be interested in the added effort of matching devices?

That was my reading as well.

[Pars]

Yes, perhaps. I hadn't taken it that way, as I assumed everyone would at least check matching.