O2 AMP + ODAC
May 14, 2013 at 7:12 PM Post #1,457 of 5,663

miceblue

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I have a few 24/192 files; how does that get translated through the ODAC's output? Does it get converted to 24/96?
^ relating to this, how does a DAC down-sample something? e.g. if I tried to play a 24/96 ALAC file on an iPhone
 
Relating to this, but slightly off-topic, this website sells up-converted "HD" albums. Is there any benefit to this, or should I not even bother and just buy the regular 16/44 album?
http://www.hifitrack.com/en/node/21496
 
May 14, 2013 at 8:17 PM Post #1,458 of 5,663

HamilcarBarca

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Quote:
I have a few 24/192 files; how does that get translated through the ODAC's output? Does it get converted to 24/96?
^ relating to this, how does a DAC down-sample something? e.g. if I tried to play a 24/96 ALAC file on an iPhone

 
The ODAC doesn't accept 24/192 input. If you're playing 24/192 files, or any other format not accepted by the ODAC, they must be converted to a supported format (e.g., 24/96) before being sent to the ODAC. IOW, your question relates to your player not the ODAC.
 

Relating to this, but slightly off-topic, this website sells up-converted "HD" albums. Is there any benefit to this, or should I not even bother and just buy the regular 16/44 album?
http://www.hifitrack.com/en/node/21496


 
There's zero benefit unless they're remastering. If they are, you may or may not find the result superior.  If they're simply "up-converting", the best you can hope for is they don't add audible artifacts.
 
Buy the CD instead.
 
May 14, 2013 at 9:03 PM Post #1,459 of 5,663

miceblue

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Quote:
Quote:
I have a few 24/192 files; how does that get translated through the ODAC's output? Does it get converted to 24/96?
^ relating to this, how does a DAC down-sample something? e.g. if I tried to play a 24/96 ALAC file on an iPhone

 
The ODAC doesn't accept 24/192 input. If you're playing 24/192 files, or any other format not accepted by the ODAC, they must be converted to a supported format (e.g., 24/96) before being sent to the ODAC. IOW, your question relates to your player not the ODAC.
 

Relating to this, but slightly off-topic, this website sells up-converted "HD" albums. Is there any benefit to this, or should I not even bother and just buy the regular 16/44 album?
http://www.hifitrack.com/en/node/21496


 
There's zero benefit unless they're remastering. If they are, you may or may not find the result superior.  If they're simply "up-converting", the best you can hope for is they don't add audible artifacts.
 
Buy the CD instead.

So if I hear stuff through my headphones with 24/192 tracks , and the ODAC doesn't support 24/192, then what does the ODAC do?
 
I figured as much for the up-converting files. I would buy the CDs but I have to pay import fees.
 
May 14, 2013 at 10:15 PM Post #1,460 of 5,663

HamilcarBarca

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So if I hear stuff through my headphones with 24/192 tracks , and the ODAC doesn't support 24/192, then what does the ODAC do?

 
The ODAC converts audio encoded in digital form (1's and 0's, a/k/a discrete) into analog form (waves, a/k/a continuous). It's these electrical waves which tell the drivers in headphones how to move back and forth, thus producing the sound we can hear. The 'DAC' in ODAC describes its purpose: It's a Digital-to-Analog Converter.
 
Your player software (or hardware) "down-converts" the 24/192 digital representation of the audio into a format the ODAC will accept (e.g., 24/96). Only then is the ODAC able to convert the "digital  audio" into "analog audio".
 
May 14, 2013 at 11:47 PM Post #1,462 of 5,663

miceblue

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Quote:
Quote:
So if I hear stuff through my headphones with 24/192 tracks , and the ODAC doesn't support 24/192, then what does the ODAC do?

 
The ODAC converts audio encoded in digital form (1's and 0's, a/k/a discrete) into analog form (waves, a/k/a continuous). It's these electrical waves which tell the drivers in headphones how to move back and forth, thus producing the sound we can hear. The 'DAC' in ODAC describes its purpose: It's a Digital-to-Analog Converter.
 
Your player software (or hardware) "down-converts" the 24/192 digital representation of the audio into a format the ODAC will accept (e.g., 24/96). Only then is the ODAC able to convert the "digital  audio" into "analog audio".

Oh okay that makes sense now. Thanks!
 
May 15, 2013 at 9:48 AM Post #1,464 of 5,663

Bojamijams

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Sorry I should've specified more.
 
My idea was to get an ODAC+O2 combo in one case with rechargable batteries.   Likewise, add a Line-Out option on it.
 
The DAC can then be powered by USB alone and give a line-out.  This would be VERY useful for driving it through a smartphone to get a line out for your car.  But obviously other applications too
 
Thus the ability to drive the WHOLE thing (DAC+AMP) without needing an external power source (hence the batteries), would be the ultimate "on-the-go" setup. 
 
I realize the original request for ability to charge the batteries WHILE playing would be pretty hard so that can be removed, but the ability for the batteries to be charged through USB would be phenomenal (especially if they can take 1A-2A charge)
 
Quote:
 
I have built several for friends/family, but used larger cases (such as Box Enclosure B3 / B4, a Hammond, and a Context Eng). I figured that in 99% of scenarios where a device needs a USB DAC, said device would be a computer, not a smartphone, so the amp just had to be transportable, not pocket portable. The DAC is bus powered so it doesnt have anything to do with the batteries, except take up too much space in the B2 case. In theory, it could be done with a smaller case but you'd have to (1) cover the ODAC in electrical tape to prevent shorts and (2) solder your battery terminals straight and very low. With the batteries touching the O2 board, you *might* have just barely enough clearance to fit the ODAC board, but again, it'd be touching the top case so you'd have to cover it thoroughly. I honestly wouldn't recommend this as the tight fit could damage that board. The batteries just take up too much space in a B2. In most cases, your terminals won't be soldered that neatly; in my current O2 that I built, the batteries themselves touch the top case and were a tight fit to slide the O2 board in, that's how tight the clearances are.
 
My recommendation? Get a B3-080 case. It's only a dollar or so more expensive from Allied Elec.

 
Quote:
 
 
 
You don't mean where the O2 is also powered off of USB, right?  
 
As mentioned above, just fitting the ODAC in is a matter of space.  No reason you can't have both the 9V batteries and the ODAC in the same enclosure, especially if the enclosure is larger than the default one.  It's just that most builders just usually put the ODAC in the space where the batteries would have been, out of convenience, when putting both ODAC and O2 in the same case.

 
May 15, 2013 at 10:33 AM Post #1,465 of 5,663

stv014

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Quote:
Originally Posted by MrMateoHead /img/forum/go_quote.gif
 
The most current Xonar DX card has 2V out, and dedicated headphone amplification through the front out / Headphone out jack. My guess is that output impedance is probably 10 ohms, given that many good computer cards use TI chips. That is also probably about twice the output voltage typical in a computer. I could not find exact specs online.

 
My Xonar D1 (the PCI version of the DX) which I have tested extensively is from 2011, and I doubt that a major hardware revision (such as adding a TI headphone amplifier) has been made since then without renaming the card. I assume your claim of dedicated headphone amplification is based on this part of the manual: "The Front Out jack has a built-in high-quality amplifier to drive headphones. Connect your stereo headphones directly to this jack." - but it is there in the manual of every Xonar card, and the specifications say nothing about a headphone amplifier. I assume if there was one, ASUS would make it more obvious to potential customers. The "front out" jack on my card (which looks the same as any picture I have seen of this model) is driven by an NJM5532 op amp, and it definitely has 100 Ω output impedance.
 
May 15, 2013 at 11:50 AM Post #1,466 of 5,663

chrislangley4253

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I did a blind A/B of the ODAC/O2 v. the Magni/Modi at a meet and the results were really disappointing. The difference between the two was minute to my ears, if it exists at all.

I can almost guarantee that any minute difference that you heard was most likely due to slightly different volumes, unless you had them volume matched.

A/B'ing good gear is always a bit disappointing.
 
May 15, 2013 at 12:19 PM Post #1,467 of 5,663

autoteleology

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I've read that volume matching needs to be done to approximately 0.2dB in order to remove loudness bias... there is no way my by-ear approximation got anywhere close, and I still heard no difference whatsoever.
 
May 15, 2013 at 6:47 PM Post #1,468 of 5,663

miceblue

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I did a blind A/B of the ODAC/O2 v. the Magni/Modi at a meet and the results were really disappointing. The difference between the two was minute to my ears, if it exists at all.

Were you expecting a large difference or something? These comparisons had been made before and the same results occurred.
 
May 16, 2013 at 1:10 AM Post #1,469 of 5,663

Greenleaf7

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Has anyone experienced the  O2 + ODAC with the following headphones? 
 
HD 650
HD 800
LCD 2
Hifiman He 500
 
I have a budget of $1000+ and plan on using the headphones for mainstream (billboard top 100) music and movies. I've been told that headphones play the biggest part in influencing sound quality,  thus I'm inclined to allocate more of my budget towards headphones. Also, i might or might not have the luxury of auditioning the above headphones with the O2 and ODAC before purchase. I'm open to suggestions for other headphones as well. Looking forward to hearing from those who have heard those phones with the O2!
 
May 16, 2013 at 1:28 AM Post #1,470 of 5,663

tintin220

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Quote:
Has anyone experienced the  O2 + ODAC with the following headphones? 
 
HD 650
HD 800
LCD 2
Hifiman He 500
 
I have a budget of $1000+ and plan on using the headphones for mainstream (billboard top 100) music and movies. I've been told that headphones play the biggest part in influencing sound quality,  thus I'm inclined to allocate more of my budget towards headphones. Also, i might or might not have the luxury of auditioning the above headphones with the O2 and ODAC before purchase. I'm open to suggestions for other headphones as well. Looking forward to hearing from those who have heard those phones with the O2!

 
Honestly, the O2 works well with everything just about, except those rare cans that require absurd gain. If you want power and literally the most neutral, audibly perfect sound, get the O2. Other amps are for if you want coloration, which you might very well prefer (I know I do), but facts are facts, and the O2's design, performance, and clarity is well-documented.
 

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