@DougofTheAbaci: At a local head-fi meet I had the WA7 connected to an ASUS Ultrabook using the ASUS power adapter and a standard, no-frills but shielded USB cable. Zero noise. None. Also using JRiver Media Center. No dropouts either. Just very clean sound.
 
The fellow next to me running a Mjolnir and W4S DAC-2 connected to a Macbook Pro was experiencing digital hash at approx 40~45 dB SPL below the playback. It added an edgy harshness to the sound. If there had been more setup time we might have been able to sort it out. With the proper power both are quite capable of great sound. The AC mains was not a clean source of power. Lots of computers in the room.

Hey Frank, have a pair of HD800 on order and am considering the WA7 to replace my Schiit stack amd simplify things. Any comments on the synergy or will that be in the review?
 
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frank i said:

I will be submitting my review this week and hopefully it will be published some time  early next week. I enjoyed my time with the WA7

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mickeyvee said:

 

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The synergy is good with the hd800.  I covered most of it in the review which has been submitted and is being worked on.. As soon as Jack Wu  fact checks it will be published. i will keep you posted.

Awesome, thanks. Looking forward to it!
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frank i said:

The synergy is good with the hd800.  I covered most of it in the review which has been submitted and is being worked on.. As soon as Jack Wu  fact checks it will be published. i will keep you posted.

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dougoftheabaci said:

Ooo. OK, now I get it. So how big of a problem is it with the WA7? Or is that determined more by the computer and if so short lot listening how can you tell if it will be an issue? I would rather know ill have to buy another device with the WA7 before I purchase if it comes to that.

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I don't think there's an easy way to predict how significant impact it will have. I suppose WA7 does some sort of power filtering to ensure no major hiccups, and I haven't seen any reports of people hearing the artifacts. I'd say you would be unlucky to notice it in your setup. For most users this is one of the things to squeeze out the last 3% of performance, after you found your perfect tubes, but perhaps before you start spending similar amounts of money on cables.

Never mind, a pure rookie Homer moment - I must have bumped the selector switch on the back of the amp by accident and moved it off of USB. All is well and amp is sounding as nice as ever with the ipad and CCK. :rolleyes:

Just ordered that Aqvox power supply, looks quite interesting.  But I was then just wondering why the WA7 doesn't separate the bus power out and provide the DAC with a clean 5v from it's own power supply, or does it?  Seems like he could be doing the same supply separation inside the WA7?
 
I am also just curious if anyone has any shots of the internals of a WA7?  Curious how everything is laid out inside.

So after using WA7 with my Win 7 64bit system I was curious is there a USB DAC which will work properly with foobar's WASAPI output so I ordered from Music Direct well prised Micromega MyDAC and got it this afternoon. So I switched it to USB 2.0 mode , installed older version 1.22 driver and switched WA7 to RCA mode and connected them using Wireworld Luna 6 cable. Then I started foobar version 1.26 and chose WASAPI event as output and music was playing without problem but I heard NO any sound quality difference comparing to WA7 with USB DAC and WASAPI push mode since as we know WA7's DAC doesn't work with event mode selected. I also tried it with ASIO output and it was working too with NO sound quality difference but there was very short silence with one of the test track   The unit I got came with old firmware so I upgraded it to the new one and then upgraded the driver to latest version and than repeated the testing steps and found no any difference so MyDAC will be returned back. 
As I said in one of my previous post I have 5 different USB cables with price ranges between $80 and $200. So after almost 3 weeks of trying them I only noticed that with 3 of them, Voodoo Magic Bus, AudioQuest Carbon and Cardas Clear Serial Buss music had a little bit more sparkle and air, the difference was small but still noticeable while compared to 2 other cables DH Labs SilverSonic and Futuretech GT-2. So if you want darker cable I would recommend DH Labs since it is cheaper than Futuretech (heard no any difference between them) but if you want more sparkle get AudioQuest since it's cheaper than Voodoo (heard no difference between them but they were slightly but noticeable better than Cardas whose price is close to AudioQuest). I'm keeping and currently using AudioQuest Carbon while foobar's output is C-Media ASIO with 32 bit depth and 6ms latency (default is 10 and smallest value is 2ms but I didn't try it)

For anyone interested my WA7 review is Woo Audio WA7 Fireflies DAC Headphone Amplifier Review

Nice review! Thanks for pointers to additional music for me to add to my library.

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atomicbob said:

Nice review! Thanks for pointers to additional music for me to add to my library.

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Thank you. Glad you liked it and the music is well recorded and fantastic to listen too.

Excellent review Frank and I completely agree with you especially when you say that for many it will be the last unit they have. My only wish is that DAC would be able to handle DSD.

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olegausany said:

Excellent review Frank and I completely agree with you especially when you say that for many it will be the last unit they have. My only wish is that DAC would be able to handle DSD.

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Thank you for the kind words. I guess at the 1K price range some choices had to be made for DSD. 

olegausany said:

...when you say that for many it will be the last unit they have.

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Considering the clientele here, I'll put big money that this will happen when cows begin to bark!

An excellent write-up, nevertheless. Thank you.

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dougoftheabaci said:

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pleasantsounds said:

Analog signal is constructed by modulating a reference level voltage, which is derived from the DC power supply. If the power level fluctuates, so will your reference level and consequently the signal will be affected.

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currawong said:

Because noise from the USB power ultimately affects the output of the DAC itself. At the very worst, in my experience, you can actually hear noises from the computer with some USB-powered DACs. That is why more expensive DACs tend to be larger, because you are paying for a larger, better-built power supply with a cleaner output (as well as other things).

Some graphs of USB power noise at the Aqvox site: http://www.aqvox.de/usb-power_en.html

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Ooo. OK, now I get it. So how big of a problem is it with the WA7? Or is that determined more by the computer and if so short lot listening how can you tell if it will be an issue? I would rather know ill have to buy another device with the WA7 before I purchase if it comes to that.

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Not so much when I compared going straight out of my MacBook Pro to using the Aurorasound Bus Power. The latter resulted in a nicer and less grainy sound, but not dramatically so. The DAC is probably at about the Dragonfly/Explorer kind of level (probably closer to the latter given the same DAC being present). I just got the WA7 back from doing the rounds around the Japanese crew here and my impression is that it is a bit grainier than my main rig, so the finer points of the sound of the DAC seem less significant, if that makes any sense.