[MatthewK]

@HeadphoneAddict: Ah, I forgot about USB power. I suppose that could possibly introduce some noise, but I wouldn't think it'd be an issue if the amp wasn't USB powered. I guess it would heavily depend on how that part of the amp was engineered. I can't hear any line noise on my XM5 with the USB DAC.

@Drag0n: I didn't think any existed, thanks for the info!

 

[MatthewK]

@killkli: I was just thinking, have you tried a ferrite bead on your USB cable to your Amp/DAC? It shouldn't affect audio quality at all since the data is just 1's and 0's but if the Amp/DAC is somehow receiving interference from the power going down the USB cable then maybe a ferrite bead would help??

 

[chesterqw]

Quote:

Originally Posted by numbskull /img/forum/go_quote.gif do you think it may sound better then X-fi DAC when used as USB DAC on computer?

if you mean the white colour x-fi external thingamajabob, yes! it does sound better

addon: everything sounds nicer when amp

 

[killkli]

Quote:

Originally Posted by MatthewK /img/forum/go_quote.gif @killkli: I was just thinking, have you tried a ferrite bead on your USB cable to your Amp/DAC? It shouldn't affect audio quality at all since the data is just 1's and 0's but if the Amp/DAC is somehow receiving interference from the power going down the USB cable then maybe a ferrite bead would help??

I hadn't tried different USB cables, but I tried the same USB device with different computer. The result is different too.
On my desktop computer, the noise is smaller due to better internal separation. I also tried to cut all other usb device off and let alone the USB DAC work. Which indeed improve the performance.

IMO, the USB doesn't work perfectly as the source of digital sound signal. It is not designed to do so. However, the problem of good digital signal is of much debate for audiophile world. So, it's still quite subjective.

As for the noise problem with my Corda Move.
It's not Move's fault but the noise of my USB signals.
And please also bear in mind that the noise is very minimal, which could only be audible via one of the most sensitive phone I have (I mean SuperFreQ, 122dB/mW & 21 ohm, which is very sensitive. Also please know that the noise is not present while using Move as a pure amp.)

For most of my other phones, this noise is non-notable.
So it's really not a very big issue.


BTW, how sensitive the SuperFreQ is? I could hear the ground noise of AMB Mini3 portable amp........

This also prove that the Headsix and Move is indeed better performance in noise regard to Mini3, because I could not hear such noise with them as with Mini3.

 

[numbskull]

well, how the external DAC thing works? it bypass the DAC of the audio player (or sounds card) ?

 

[MaxAmplitude]

Quote:

Originally Posted by Asr /img/forum/go_quote.gif The main detraction I found with it was a range of sonic omissions when used as a USB DAC

Based on ASR's review, and similar input from other head-fi members, we've completely replaced the DAC used in the XM5. The new DAC is the PCM2702 from BurrBrown/TI, and is a substantial improvement we are very happy with. At the same time (also based on head-fi suggestions) we swapped the input and output frontpanel jacks, to better accomodate oversize headphone plugs.
The new dac has been shipping on all units since June08. Link is here.

Thanks everyone for your input!

 

[Keppel]

Quote:

Originally Posted by MaxAmplitude /img/forum/go_quote.gif The new DAC is the PCM2702 from BurrBrown/TI, and is a substantial improvement [and] has been shipping on all units since June08.

I think every single XM5 review on this site is based on the old DAC, even the new reviews, posted after June 2008. I wonder what the deal is? Do these reviewers have the old equipment laying around, and review it 1.5 years later?

 

[Keppel]

Quote:

Originally Posted by numbskull /img/forum/go_quote.gif well, how the external DAC thing works? it bypass the DAC of the audio player (or sounds card) ?

The DAC would bypass the sound card of your computer. For, say, a portable audio player like an iPod, the DAC on the headphone amp wouldn't come into play at all. (There's a switch that toggles between these two modes) The analogue audio from your portable simply gets amplified by the headphone amp.

 

[HeadphoneAddict]

My review puts the XM5 new DAC on the level of the 3MOVE and Predator's DAC - very good but still below the Pico DAC (duh, ASRC upsampling to 24/96 with Wolfson WM8740). See my public profile "about me" for links to the review. I do like the amp a lot.