The Objective2 (O2) Headphone Amp DIY Project

[RocketScientist]

Originally Posted by Alexium

Guys, could someone please give me a run-down on the currently known bugs in O2?
P. S. is there any assembly instruction, other than the one in RocketScientist's blog? I have finally received my kit, but somehow I don't feel I'm prepared to assemble it just yet.

See:

Important Details

And:

Circuit Board Construction

And the latest PDF and XLS files at:

O2 Resources

I've been updating the above 3 sections regularly as issues come up.

[cheapskateaudio]

Originally Posted by RocketScientist

Oh, he's a uDAC owner! That explains a lot (for those not aware I found some significant problems with the uDAC-2 a long time ago which didn't go over very well with many of the NuForce Faithful). Anyway... hopefully we can all get back to more constructive topics here. Let's not let one person try to turn diyAudio into H-F.

I am not a big uDac/nuforce fan, I just found it to be reasonable given the cost and features. From a purely subjective standpoint I like how it sounds with certain types of music. Even the O2 with absolutely bottom barrel parts is more than either uDac 1 or 2 and obviously doesn't include a DAC.

I found your uDac rant kind of weird RS because in another article you claimed that the uDac's sound was second only to the Benchmark dac in a blind test... Kind of makes your resulting tear down of the uDac look redundant. I mean, is the point to satisfy the measurements or to be second in subjective performance only to the Benchmark DAC?

[sofaspud]

Alexium, the only "bug" I'm aware of is that with the September BOM resistor values, the power management might not latch into shutdown mode and will toggle off and on. I suppose a person could as easily say this is a problem with the batteries, not the amp. The newer BOM adjusts the values in an attempt to overcome the issue. Using either set of values, it will be time to recharge the batteries.

[RocketScientist]

Sorry Cheapskateaudio, after pointing out "we're all deaf and have no clue" I'm afraid we can't offer you much here. What good are the deaf and clueless? Please go ask your questions somewhere else and stop SPAMMING and/or TROLLING this thread.

[idjoel2000]

Originally Posted by RocketScientist

Sorry Cheapskateaudio, after pointing out "we're all deaf and have no clue" I'm afraid we can't offer you much here. What good are the deaf and clueless? Please go ask your questions somewhere else and stop SPAMMING and/or TROLLING this thread.

come on rsa, just ignore him already

[Jokener]

@ CSA: 50€'s say you are making stuff up!
I just recently assembled my first own O2 after sending out all the kits for people in the GB.
It was built using a cheap, unregulated soldering station built BEFORE the last war (and I live in Germany, we don't have many wars around here) by someone (me) with mediocre (at best) soldering skills.
I have successfully used it to drive a Medusa headset (more power hungry than HD650), a few HDXXX series headphones, my Shure SE530 cIEM's and a few others, all without problems.

But I am prepared to put my money where my mouth is.
I am offering you 50€ (which is more than the parts cost) for your bad sounding O2.
And when I get it, I will put it up and measure it against a few of my own O2s I will have built by then.
And I will publish the results here and on Head-Fi ( -.- ) to show what was really wrong with your O2.

Your turn!
Do you fold and give up?

[cheapskateaudio]

Originally Posted by sofaspud

"Is that the one recommended for regulators located an appreciable distance from the filter caps?"
CSA avoids stating it, but it's right there on the first page of the datasheet.
I'll also point out the second bullet: "No External Components Required"

How can both statements be true? Clearly you lack the ability to understand subtle phrasing of meaning. "Required" != "recommended".

[RocketScientist]

Great idea Jokener. If he ignores your very generous offer, and keeps it up, I'll talk to the admins here. They don't want diyAudio to turn into H-F either.

[qusp]

CSA really is an insane person. ignore the troll he changes his story, changes his thoughts, changes his words; all in an effort to gain a reaction

[Willakan]

Moving on from cheapskate (I think bothering with what he has addressed to me, what he has addressed to NwAvGuy and what he has said regarding the amplifier design is no longer worth anyone's time) I have enjoyed listening to my O2, which incorporates RCA jacks and a PCB-mount headphone jack (secured below with the finest audio-grade glue after I realised it wasn't going to go in any other way) into the front panel.



The only thing I would draw from this build is that you shouldn't make the same mistake I did and not do the maths for the gain settings you want! I simply assumed that 3X gain would be appropriate for the K702s and now have an amp which requires very careful volume knob usage! Channel balance seems fine though, so I'm not overly fussed.