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O2 AMP + ODAC - Page 139

post #2071 of 5263
Quote:
Originally Posted by adydula View Post
 

For you guys that think that the O2 will "work better or sound better???" on el crapo PC usb 5 volts I have used the ODAC on over 20 pcs of all types and flavors. I also used and external very high dollar DC power supply and I could not hear any real audible differences.

 

All the measurements that the designer took and are published on the other site meet or exceed anything that might cause the loss of transparency etc or the ability of it to do what it was intended to that is to be a excellent digital to analog convertor.

 

The ODAC like the O2 was and still is an experiment to prove to the world that great audio can be had at less than astronomical prices....

 

Unless you really have a really poor PC USB implementation and violate the USB specs there should be no real world difference in what the ODAC does.

 

You can easily splice pure DC to power the ODAC to see what "pure DC" will do.....simple DC batteries have no AC ripple or warts...even mega buck AC to DC power supplies have issues....

 

All the best

A.

 

The main reason why I'm interested on the doodlebug is primarily because I have other DAC's that cannot have the same regulated power implementation as the ODAC (i.e: ELE DAC EL-D01 that goes for $15 max). If I truly cannot hear a difference on the ODAC, then I am free to use it somewhere else. I'm sure my USB microphones may benefit from a cleaner power.

post #2072 of 5263

USB power in PCS do present potential issues:

 

Audio Out voltage: The voltage can be as low as 4.5 volts. Add potential losses from power filtering and other DAC and op amp circuitry. So your lucky to get 4 volts peak to peak output swing without clipping. Do the math this is 1.4vrms which is short of the redbook standard for output of 2 vrms. This turns out to be 3db less than the redbook 2vrms standard. That's a potential loss of 3db of dynamic range compared to other redbook standard devices like a cd player and most DIY dacs have this shortcoming.

 

Possible Greater Noise:

 

Yes USB power is potentially dirtier than a dedicated regulated DC power supply.So this means the design of the DAC for 16 bit performance needs some attention. Extra filtering and good design. There are dacs that tout 24 bit performance but in reality do not deliver this performance.

 

Jitter related to Power and or ground "noise"...this can be influenced by a crappy USB power source. The noise can affect by modulating the digital bit stream creating jitter.

 

The ODAC was designed with all the above plus more in mind. The designer's careful design and by using the right components has overcome the issues from a crappy USB power supply. Remember that most USB power sources in modern day PCs can almost always source 500ma. There are some exceptions...go read about these on a different site.

 

Also remember even if you do use an external mega buck regulated DC supply the USB Dac still has to be connected to the PC and noise can still come into the DAC and cause issues if its not properly designed or filtered. The ODAC has different power supply filtering for the digital and analog sides. Also capacitor selection and the use of inductor filtering helps to reduce the USB issues so they are essentially non-issues.

 

 As I have discovered an independent power supply doesnt really do anything or make much difference. Also the ODAC delivers the 2vrms redbook standard! Which is that 3db dynamic range issue. Some USB dacs are deficient in this area.

 

The ODAC also was optimized for the lowest jitter related to the power source. Both the best noise reduction and distortion reduction and the lowest jitter. This was found in not only the design, but the physical layout of components. Lots of electronic stuff really look "pretty" but the ODAC doesnt win awards for how it looks, but how it performs. The ODAC is very quiet...with a -60dBFS signal, it had an impressive 112dB of dynamic range, and that was with the prototypes! The $1600 Benchmark DAC1 was measured at 111dB.

 

Modern day CDs have 96dB of dynamic range. I could go on and on and on..... but go read for yourself. For $99 this is the DAC deal of all times. Enjoy.. A.

post #2073 of 5263

Hi guys

 

Just a bit of a quick update, I put my O2 kit together last week for some tests and it's sounding promising on the Grados! Personally I had no 'ZOMG' moments, but the little extra bass on stuff like AC/DC and Muse is welcome, I can't wait to see how things change as my brain adapts. Now just to fit the ODAC in the same case so I can use the batteries! :tongue:

post #2074 of 5263

Hey Jacob....

 

Yes there are other USB devices that if not designed well might be impacted by "polluted" USB power....

 

A.

post #2075 of 5263

locksbury...

 

post some pix of your project and let us see how you fitted the ODAC in the O2 assembly...

 

Alex

post #2076 of 5263
Quote:
Originally Posted by locksbury View Post
 

Hi guys

 

Just a bit of a quick update, I put my O2 kit together last week for some tests and it's sounding promising on the Grados! Personally I had no 'ZOMG' moments, but the little extra bass on stuff like AC/DC and Muse is welcome, I can't wait to see how things change as my brain adapts. Now just to fit the ODAC in the same case so I can use the batteries! :tongue:

 

I think this is the case for many music setups. I think quick A/Bing provides only part of the answer.

 

Bob Graham

post #2077 of 5263

Toms Harwardware set up an blind test of the DAC2, O2/ODAC, Asus Xonar, Realtek 889:

 

http://www.tomshardware.com/reviews/high-end-pc-audio,3733.html

 

Conclusion? Any more than $2, and you are buying "features" - not distinguishable performance. Wonder how that would sit with some of the other forums lol. The weak spot was that there were just 2 listeners that had good equipment themselves, but not necessarily any formal training.

 

I am currently using the ODAC with a desktop amp / 2.1 setup and couldn't be more pleased. Sounds awesome - luckily, the amp has no noise or problems I can detect. Needed a break from headphones. I enjoyed my own realtek chipset long enough, but wouldn't give up the O2/ODAC, its too good. :wink_face:

post #2078 of 5263

Its a simple design, but the wonder is what the designer went thru and did to make it as good as it is....."is the rest of the story".

 

Taking the time to do layouts, over and over and over just to get the measurements as best possible....

 

Trying to match reference circuit measurements or best them...this is wonderful engineering...and we all benefit!!

 

Ah....such a great time to be in audio!!

 

A.

post #2079 of 5263

You really need to stop drinking the koolaid, i mean seriously dude its getting a little obsessive.

post #2080 of 5263
Quote:
Originally Posted by mcandmar View Post
 

You really need to stop drinking the koolaid, i mean seriously dude its getting a little obsessive.

No, it's the O2 and this is typical for threads dealing with it :cool:....fierce defenders and seriously critical opinion, usually ends in shouting matches.  I take the middle ground:  respect for what the designer did but it's not the last word in amplification by a long shot.  And scr*w kool-aid, have a beer :beerchug:

post #2081 of 5263
Quote:
Originally Posted by Xenophon View Post
 

No, it's the O2 and this is typical for threads dealing with it :cool:....fierce defenders and seriously critical opinion, usually ends in shouting matches.  I take the middle ground:  respect for what the designer did but it's not the last word in amplification by a long shot.  And scr*w kool-aid, have a beer :beerchug:

My view is a bit simpler:

 

If you found Heaven in your audio setup: Feel free to defend it, but I may or may not care.

If you still haven't found it in your setup : Feel free to defend it anyhow, it's your hard earned cash.

If you're defending something that is poorly designed: Please see me ignoring you as a compliment.

 

Not saying that the O2 or ODAC is poorly designed in any way shape or form, the "open hardware" part of it just seems so ignored, even more so on the ODAC which seems baffling not to be DIY/mod friendly.

post #2082 of 5263

Can anyone compare the o2/odac with magni/modi?

post #2083 of 5263
I was going to respond, but then I saw Magni/Modi. I can chime in about the Vali vs O2 though. XD
post #2084 of 5263

the vali has ringing problem now. many people can't stay with it.

post #2085 of 5263
Quote:
Originally Posted by sonic2911 View Post

the vali has ringing problem now. many people can't stay with it.

I...don't even understand why that's there. That's a fundamental problem that shouldn't exist in any amplifier. That's just plain stupid.

For anyone wondering, when you plug in a headphone, any headphone, into the Vali's headphone out port, a ~2 kHz or so signal gets played through your headphones at a set volume level and you can't do anything about it other than wait it out for a few minutes.
Edited by miceblue - 2/25/14 at 6:25pm
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