[stv014]

I recommend reading this thread for information on PC based measurements. The most likely reason why you get poor SNR is that there is a ground loop between the ODAC and the X-FI HD USB, since both are connected to the same PC. If that is the case, try using a USB isolator, or two separate isolated computers (e.g. a PC and a battery powered laptop) for playback and recording.
A simple example that shows how much difference a grounding problem can make: with a direct loopback between my Xonar D1 and STX (in the same machine), I get a noise floor of about -92 dBA. Adding a differential amplifier to eliminate the ground loop improves that to better than -113 dBA (the Xonar D1 is advertised as having an SNR of 116 dB, which is a realistic value once the additional noise from the differential amplifier and the ADC of the Xonar STX is taken into account).

 

[stv014]

Quote:

And to be honest I cant hear any difference between creative x-fi + O2 amp vs. ODAC + O2.. both with HD600.

 
If the X-Fi already has a good enough DAC, then it is hard to notice a further improvement, assuming there is any. After some point, the error introduced by the DAC to the signal becomes inaudible, and an upgraded one will sound the same if both are designed to be transparent (some "boutique" products are not).

 

[Dano91]

Thx a lot! I will try to measure it again with two separated pc`s, hopefully there will be some differences in numbers Btw, this ground loop problem doesnt show when looping the same device on one computer? (e.g. x-fi line out -> x-fi line-in)

 

[stv014]

It normally does not affect a simple line out->line in loopback with a single device.

 

[zilch0md]

I've posted a comparison of the ODAC with the CEntrance DACport LX and iBasso DB2, here.
 
Thanks,
 
Mike

 

[imackler]

Hey all!
 
1st time dac user. I'm getting a lot of cutting out with my ODAC > O2. It's happening whether I use foobar or media player, whether flac or 320 kbps. I just mention this because I'm trying to narrow what the options are. It's like there is skipping, but not quite as long as when a cd skips. More like when a headphone jack jostles. I've jiggled all the jacks and can't find anything. Of course, it happens when I'm perfectly still. I've also tried two different usb cords, a monoprice 4' and a sansa clip 8" or so. Its not constant but happens as soon as you're enjoying the music, about every 20 or 30 seconds. Its really jarring. 
 
Any ideas where I should start my troubleshooting? 

 

[gnarlsagan]

Quote:

I've posted a comparison of the ODAC with the CEntrance DACport LX and iBasso DB2, here.
 
Thanks,
 
Mike

 
Great review. I will spend a lot of time now looking for slight etch in the highs. 

 

[LouisLoh]

Quote:

Hey all!
 
1st time dac user. I'm getting a lot of cutting out with my ODAC > O2. It's happening whether I use foobar or media player, whether flac or 320 kbps. I just mention this because I'm trying to narrow what the options are. It's like there is skipping, but not quite as long as when a cd skips. More like when a headphone jack jostles. I've jiggled all the jacks and can't find anything. Of course, it happens when I'm perfectly still. I've also tried two different usb cords, a monoprice 4' and a sansa clip 8" or so. Its not constant but happens as soon as you're enjoying the music, about every 20 or 30 seconds. Its really jarring. 
 
Any ideas where I should start my troubleshooting? 

 
Is it an integrated unit? Try another USB DAC if you have one. Then feed the O2 with analogue from another source, perhaps a portable player.
 
If it's two separate pieces, try another headphone amplifier, and another I/C.

 

[adydula]

imackler,
 
Several things...one is to check the pre-buffering settings. dependng on the PC, Dac, OS and or playback software this may have to be adjusted.
 
Also I had a pop / tic issue on one system and not another and it was a corrupted file...
 
Alex

 

[fenderf4i]

Quote:

 
Great review. I will spend a lot of time now looking for slight etch in the highs. 

 
lol are you serious?

 

[gnarlsagan]

lol are you serious?

Haha yeah but I don't think my iems are resolving enough to find it if it exists. Zilch0md seems pretty convinced of this slight lack of resolution in the highs after his blind test.

 

[lukeahale]

His description sounded to me more likely to be a power issue, as though the ODAC is clipping? It seems to be common with the ODAC(luckily I have not had issues myself).

 

[zilch0md]

Yes, that was the conclusion reached in my e-mail exchange with JDS Labs - that it was a power issue - but the DACport LX didn't suffer these anomalies when running on the same USB port, same laptop, same USB cable.
 
The DACport (not to be confused with the DACport LX) actually contains five independent power supplies in its circuitry.  Here's a CEntrance blog that includes a discussion of DACport power management.
 
Anyone who's having power-related problems with the ODAC (or any other USB-powered devic)e might be interested in getting...
 
...one of these...  MicroTik 5VUSB Power Injector
 
 

 
 
 
...and one of these...   5V 2A Power Supply terminated with a 1.3 x 3.5mm barrel connector
 

 
Together, they can supply a USB device with up to 2.0 Amps of regulated 5-Volt DC power that's not shared with any other USB devices.  (This solution requires, however, that you use your USB DAC within reach of a 120V AC outlet.)  

 
Note:  I've ordered these, but I haven't received them yet.  Anyone interested, might want to wait before placing an order yourself, until I've had time to confirm that this contraption actually works.  

 
I'll post a follow-up when I've done so.
 
Mike

 

[chrislangley4253]

Quote:

Yes, that was the conclusion reached in my e-mail exchange with JDS Labs - that it was a power issue - but the DACport LX didn't suffer these anomalies when running on the same USB port, same laptop, same USB cable.
 
The DACport (not to be confused with the DACport LX) actually contains five independent power supplies in its circuitry.  Here's a CEntrance blog that includes a discussion of DACport power management.
 
Anyone who's having power-related problems with the ODAC (or any other USB-powered devic)e might be interested in getting...
 
...one of these...  MicroTik 5VUSB Power Injector
 
 
 
 
 
 
...and one of these...   5V 2A Power Supply terminated with a 1.3 x 3.5mm barrel connector
 
 
 
Together, they can supply a USB device with up to 2.0 Amps of regulated 5-Volt DC power that's not shared with any other USB devices.  (This solution requires, however, that you use your USB DAC within reach of a 120V AC outlet.)  

 
Note:  I've ordered these, but I haven't received them yet.  Anyone interested, might want to wait before placing an order yourself, until I've had time to confirm that this contraption actually works.  

 
I'll post a follow-up when I've done so.
 
Mike

awaiting your update

 

[adydula]

Mike,
 
Good that you found a solution, I hope it works.
 
Its odd that the ODAC does this...the current draw is only 125 ma from what I know.
 
I had this type of issue of dropouts with a HRT MSii+ USB dac that draws 400 ma. on one pc in particular....its a homebuilt system.
On a commercial system it worked fine with default pre-buffering settings. But not on the homebuilt. The ODAC on this homebuilt system works just fine.
 
I am testing a few pcs for voltage drop and current draw in the real world with a modded usb cable, voltmeter and ammeter.
 
I will post some results later this week.
 
Do you know what the current draw spec is for the Centrix?
 
All the best
Alex