CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS
Main Deck => Discussion for Registered Members Only => Topic started by: HideousPride on October 01, 2014, 09:56:06 PM
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So one of the most requested products on Massdrop is the O2/ODAC combo. No surprise. But the ODAC board is currently out of stock and is proprietary. We had a thought - we know manufacturers who have stuff, and we know engineers. Let's try to build something that sounds good, is affordable, and has all the inputs and outputs people want.
Initial results below!
(http://i.imgur.com/rKuZtaC.jpg)
Specs
DAC PROCESSOR ES9023
USB CONTROLLER CM6631A 384KHz asynchronous
OP AMP JRC 2068 aka NJM2068
PCB High quality 24K GOLD 2 Layer PCB
INPUT 3.5 Ø (L/R) Channel
HEADPHONE Gold Coated 6.5 Ø JRC 4556AD+JRC 4556AD
Power control DC - DC DC5V/+-12V
Power adapter DC5V 1.5A
We have two prototype boards that we can ship out, would be curious to hear what ABS+ pirates think. Mac only for now, Windows drivers still in development. 1/4" headphone output. Wish list of what improvements we could potentially make, if a more premium chassis is something we should consider, along with anything else you can think of would be great feedback for us.
Not sure that it'll become something we actually list on our site, as of right now it's more of a "Let's build it and see where it goes" attitude.
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This looks interesting! Is it a similar concept to the Project H?
http://www.head-fi.org/t/652306/diy-custom-amplifier-and-dac-project-h
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Mac only for now, Windows drivers still in development.
Do not forget Linux. Ensure USB Audio class compliance! :)p6
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This looks interesting! Is it a similar concept to the Project H?
http://www.head-fi.org/t/652306/diy-custom-amplifier-and-dac-project-h
Wow, someone actually remembers our project!!!
Isn't there also the issue of the O2's license not allowing derivative PCBs based off it? I also thought the general consensus on CS was that the O2 wasn't in line with very many member's tastes...
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I also thought the general consensus on CS was that the O2 wasn't in line with very many member's tastes...
Pretty much. In fact, most of the members here that I know that tend to side with the objective perspective don't even use the O2 for primary listening if that tells you something. But they tend to be the rational objectivists, not the religious zealot types. The latter ones don't seem to last long here. Usually ends up looking like a bird trying to fly though a glass window.
But there is a market for that ODAC/O2 so why not. I find it funny and ironic that the ODAC and O2 are largely marketing driven with the idea that those are the last audio components you will ever need to buy to get honest, accurate and transparent audio reproduction. Hah.
Still, the ODAC has been my portable reference DAC for awhile until the Geek Out replaced it based on cost and performance. Marv uses my O2 for measuring headphones. Better to let his mic listen to it than me.
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Pretty much. In fact, most of the members here that I know that tend to side with the objective perspective don't even use the O2 for primary listening if that tells you something.
I find it funny and ironic that the ODAC and O2 are largely marketing driven with the idea that those are the last audio components you will ever need to buy to get honest, accurate and transparent audio reproduction. Hah.
Interesting, I thought the ODAC/O2 was really famous/popular here, because of its "supreme accurate audio" :-Z
I know that it`s completly off-topic (and feel free to delete or edit my post) but what are the thoughts of people here about Nwavguy?
When I started to search about this hobby I found lots of things about him, and thought "wow, this guy is a genius!". But after a while ... a guy who appears from nowhere and disapears mysteriously and between this time develop some products that are kind of hard to make and starts to claim that all audiphile expensive things are shit my thoughts started to change...
popcorn
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On nwavguy, basically can't believe that he become a "genius" by chaining two CMOYs together and sticking a volume pot between them and figuring out how to use a dscope.
http://tangentsoft.net/audio/cmoy/ (http://tangentsoft.net/audio/cmoy/) .....since 2001.
I respect his masterful marketing of himself though. Makes sense though. He totally captured the starving student market and appealed to a good subset angry at the world because college never resulted in what was promised.
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Long story short, I bought into nwavguy for a while and took his word as gospel. Then I compared the O2/ODAC combo against the Leckerton UHA-6S MkII. Both measure excellently and should thus sound identical (beyond human hearing capabilities), if nwavguy's claims were correct. I heard a clear difference that was outside the realm of placebo with a few different headphones. That's when I realized there was much more to it all than he was claiming, and I started down a different path of learning. It's good to be skeptical and understand your possible biases and limitations, but sometimes you need to trust what you hear subjectively.
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Long story short, I bought into nwavguy for a while and took his word as gospel. Then I compared the O2/ODAC combo against the Leckerton UHA-6S MkII. Both measure excellently and should thus sound identical (beyond human hearing capabilities), if nwavguy's claims were correct. I heard a clear difference that was outside the realm of placebo with a few different headphones. That's when I realized there was much more to it all than he was claiming, and I started down a different path of learning. It's good to be skeptical and understand your possible biases and limitations, but sometimes you need to trust what you hear subjectively.
This is about how it went with me, as well. Had O2 for a while, but bought Leckerton UHA-6s Mk II based on things I saw here, knowing I had a 30-day trial period with it. I wanted to see if I could hear the difference. Needless to say, I kept the Leckerton.
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It's all placebo you fuckers. Y'all crazee.
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It's all placebo you fuckers. Y'all crazee.
Bah, don't tell me that! You just biased all my future listening.
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Y'all crazee.
Well, yeah.
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This looks interesting! Is it a similar concept to the Project H?
http://www.head-fi.org/t/652306/diy-custom-amplifier-and-dac-project-h
Wow, someone actually remembers our project!!!
Isn't there also the issue of the O2's license not allowing derivative PCBs based off it? I also thought the general consensus on CS was that the O2 wasn't in line with very many member's tastes...
Yeah, I would have loved to have participated in that project!
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I never really fell for the Objective thing, but I was very interested to hear the combo for myself. I finally did and thought it didn't sound bad, but it didn't sound that good either.
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I used to think that the Objective 2 amp was the best thing until I actually built it. Then again it is very viable to build these commercially as most of the advertising is done for you. Must be the reason why I sold mine for 100$ profit.
I say - do opamp driven discrete buffers, instead of the opamp mantrain.
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I never really fell for the Objective thing, but I was very interested to hear the combo for myself. I finally did and thought it didn't sound bad, but it didn't sound that good either.
It just sounds lifeless really, but then again its probably better than most onboard soundcards.
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I never really fell for the Objective thing, but I was very interested to hear the combo for myself. I finally did and thought it didn't sound bad, but it didn't sound that good either.
It just sounds lifeless really, but then again its probably better than most onboard soundcards.
That's definitely true. I suppose we can say that building an amp to excel at rudimentary specs means it won't suck.
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Hideouspride this seems like a great idea, I think a lot of people are turned off by the combo o2/odac hideous enclosure and having the ports on the wrong sides. For a later project maybe you should get with agdr on diyaudio he has a design for an objective desktop amp that is pretty mature already
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Hideouspride this seems like a great idea, I think a lot of people are turned off by the combo o2/odac hideous enclosure and having the ports on the wrong sides. For a later project maybe you should get with agdr on diyaudio he has a design for an objective desktop amp that is pretty mature already
Thanks for that. Agree that the casing could be much more attractive, and to be honest I feel one of the legitimate considerations for many people these days are the aesthetics. Will's handling the DIY audio section for now, I'll definitely ask him to keep an eye out for AGDR's project as it looks like they've already put a lot of work into it.
It's one of those interesting things I've learned since starting at the company. Part of it is sourcing products I really like and am passionate about (CustomArt Harmony 8 Pro), but another portion of it is just delivering exactly what the community wants (ATH-M50x, O2/ODAC). It's an interesting balancing act.
The O2/ODAC was actually my first starting point after reading up on so many of the positive things said about them. Listened to a Fostex HP-A8C some time later and revised what I thought. It may very well be the Beats by Dre of the DAC/amps, and I guess that's fine with us. If it serves as an initial springboard for some to explore the field of DACs and amplifiers, there's definitely value to be found in having the product on our site.
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The problem with the springboard idea is that FiiO latest products are actually better.
E18 for thicker sound, E17k for leaner more forward - stemps from OPA642 vs AD4970 difference. DAC is actually noticeably better in E18 - while E17k is worse DAC than ODAC, E18 is comparable.
Leckerton w/ OPA209 is on the leaner side without the forward part, 2x more expensive with a really outdated DAC part.
For the $150 it costs (vs $300 for Leckerton), it is a winner.
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A Vout DAC chip like the ES9023 or PCM5102A is going to have noise floor modulation due to the embedded charge pump, limiting its performance.
TI recently released the PCM5242, which is a PCM5102 with embedded ROM/DSP, as well as differential voltage output, rather than single pole output. This makes it similar to the Wolfson chips, except with the added benefit of a line driver. Differential output will help with cancelling out some of the output noise, which makes the performance ceiling of this chip package higher, while remaining pretty affordable. A designer still needs not design an I/V converter (lowering complexity and BOM cost), and can directly hook up a differential input IC for the headamp, further simplifying BOM cost.
The embedded ROM allows for custom design of digital filters and oversampling routines, and can be selectively flashed for performance changes, like an FPGA, except with a less computational power.
A platform like this would end up more flexible than the ES9023 used right now. TI even has a reference design based around it and the TPA6120A2 (though I wouldn't recommend this design, as it has problems, OI being just one of them).
http://www.ti.com/lit/df/tidrbs8/tidrbs8.pdf
http://www.ti.com/lit/ug/tidu639/tidu639.pdf
http://www.ti.com/tool/tida-00385
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To serve market demands, get the O2/ODAC combo. Eventually the market will come around to the CS community perspective, but not for a while.