[TheGrumpyOldMan]

Well, you can start troubleshooting by taking Audirvana out of the equation: Make sure it's closed (I believe it may have exclusive device control), then open Audio MIDI Setup in Applications/Utilities/ (part of every OS X install). With the WA7 properly connected, the options should look like this:
 

 
If this does NOT show the above, something's wrong with the USB connectivity to your WA7. If it does, something's wrong with your Audirvana setup. I personally use BitPerfect, and it works fine in Mavericks via USB3.

 

[incursore61]

OK VERY TANK'S
 
marco

 

[HiFiGuy528]

  Well, you can start troubleshooting by taking Audirvana out of the equation: Make sure it's closed (I believe it may have exclusive device control), then open Audio MIDI Setup in Applications/Utilities/ (part of every OS X install). With the WA7 properly connected, the options should look like this:
 

 
If this does NOT show the above, something's wrong with the USB connectivity to your WA7. If it does, something's wrong with your Audirvana setup. I personally use BitPerfect, and it works fine in Mavericks via USB3.

 
Thank you!  + 1 
 
No issues here on OS X latest 10.9.4 with MacBook Pro Retina display USB 3 and MacBook Air USB 3.  I use BitPerfect and Amarra.

 

[karmanfamily]

I don't like to brag, but finally my new power supply came in and it is PRETTY!!!
Didn't have a chance to hear the difference yet, if any... Frankly, I don't care if sound doesn't improve.. It looks so much better!
 
Anyone have any personal experience with the new power supply?

 

[JoelT]

  I don't like to brag, but finally my new power supply came in and it is PRETTY!!!
Didn't have a chance to hear the difference yet, if any... Frankly, I don't care if sound doesn't improve.. It looks so much better!
 
Anyone have any personal experience with the new power supply?

While I appreciate that it looks nice, the sound quality is what matters to me above all. Thankfully it's awesome:
 
http://www.head-fi.org/t/715375/woo-audio-wa7tp-tube-power-supply-impressions-thread/165#post_10547802

 

[karmanfamily]

And yes! It sounds great!
The background was dead quiet already and at full volume without anything playing you hear.... nothing!
Things seem to sound a little cleaner and bass is more tight and defined.
One thing I can't really explain and is more a feeling than hearing. It feels like what is fed to the headphones is more natural.
Female vocals have more emotion, you can hear the little trembling in the voice better.
 
in my ears the difference is not huge, but it definitely is worth the purchase. It brings the WA7 to the next level.
 
(I do have to add that I have them connected to a Audio Power Industries power conditioner with PS Audio and Wireworld power cables and I am using an iFi USB purifier and a Wireworld USB cable. All this probably helps too)

 

[KazeNg]

How does the HD800 sound like when pairing with the WA7?

 

[HiFiGuy528]

  How does the HD800 sound like when pairing with the WA7?

 
Should consider EH gold-pin 6C45 tube upgrade and WA7tp for HD800 pairing.

 

[JoelT]

  How does the HD800 sound like when pairing with the WA7?

As Mike mentioned, the HD800 will benefit a from the WA7tp (tube PSU) as well as the tube selection in both the WA7 & WA7tp. The internal DAC is good enough to get started with, but the HD800 will also benefit from an external DAC running in to the WA7. When fully upgraded sound is truly excellent: slightly warm but not overly "tubey", dynamic yet smooth, with excellent staging, separation and imaging. I'd certainly recommend it for the price.

 

[mediumraresteak]

Has anyone heard the new WA7 upgrade and the X-Sabre when pairing with the HD800?  I'm still using the original WA7 so I'm open to both options.

 

[HiFiGuy528]

  Has anyone heard the new WA7 upgrade and the X-Sabre when pairing with the HD800?  I'm still using the original WA7 so I'm open to both options.

 
I'll have to get my paws on the X-Sabre at the LA meet.  Heard good things about it.

 

[mediumraresteak]

   
I'll have to get my paws on the X-Sabre at the LA meet.  Heard good things about it.

Hey Mike, were you able to demo the X-Sabre at the recent meet?  Thoughts versus the WA7tp?

 

[HiFiGuy528]

  Hey Mike, were you able to demo the X-Sabre at the recent meet?  Thoughts versus the WA7tp?

 
I was busy at the Woo Audio table and did not get a chance to hear it.  

 

[MaKa13]

I observed some behaviour from the WA7 that I have which made me wonder if it is a defect in my copy or it is something by design, or something else.
 
I had the tablet fully charged and connected it to the WA7 using the USB cable, listened to some music and then turned off the WA7 (Tubes went off) in the morning the tablet battery was drained. That table can stay for couple of days in idle mode which it died over night when connected to WA7.
 
It made me ask whether WA7 draw power from USB? If yes, does it draw power even when the WA7 power button is off? 
 
Cheers!

 

[PleasantSounds]

  I observed some behaviour from the WA7 that I have which made me wonder if it is a defect in my copy or it is something by design, or something else.
 
I had the tablet fully charged and connected it to the WA7 using the USB cable, listened to some music and then turned off the WA7 (Tubes went off) in the morning the tablet battery was drained. That table can stay for couple of days in idle mode which it died over night when connected to WA7.
 
It made me ask whether WA7 draw power from USB? If yes, does it draw power even when the WA7 power button is off? 
 
Cheers!

 
The DAC in WA7 is powered via USB. You could for example use the RCA outs to feed the signal to some other device - and in that mode the amp can be off. The power switch does not affect it.