Ayre Acoustics QB-9 DSD

Stereophile Class A rated, Product of the year for good reason.  This DAC simply sounds fantastic. Michael Lavgorna granted it an Audio Stream Greatest Bits award. It does one thing and one thing only, converting digital from a single USB input into weighty, non fatiguing, analog via balanced or single ended outputs. I've had an Auralic Vega side by side and can  say both are excellent. Some people like chocolate, some like strawberry.
The DSD version uses a Sabre chip, custom FPGAs, Ayre's own Minimum Phase filter, and provides its own power to the USB input so there are no issues with the limited power from the computer's USB bus. It is an extremely well engineered product and has provided years of trouble free service. Plenty of reviews available on line extol the virtues of this DAC which represents almost a complete rebuild from the original QB 9. In fact Ayre discovered some additional parts and apparently made another small run of this model. But I don't recall where exactly I read this.  From Ayre's Website: 

Ayre is proud to be the first licensee of Wavelength Audio’s new “asynchronous” USB technology called
Streamlength software. For the first time ever, Ayre can make an external D/A converter box that has the
critical master audio clock where it belongs—right next to the D/A chip itself, and without resorting to a
non-standard interface.This external D/A converter box can be connected to virtually any computer running either Windows or
Mac operating systems via the standard USB port. One can choose his favorite music playback program and
enjoy all the power and flexibility that computer-based audio offers, while still enjoying state-of-the-art
sound from his music system. In addition to the ultra-low jitter achieved by putting our own custom-designed master audio clock in the
D/A converter itself, the Ayre QB-9 offers a host of other features that make it a true breakthrough
product for computer-based audio. As with all other Ayre products, the analog circuitry is fully-balanced
and zero-feedback for a natural sound with the correct pace and timing.Taking a chapter from the design of our D-1xe DVD player, the USB receiver section is isolated from the
rest of the audio circuitry with high-speed opto-isolators. This means that the RFI generated by the multi-
tude of clocks operating inside the PC and its noise-generating switching power supply is completely kept
out of one’s music system. Finally, we’ve included our new “MP” minimum-phase digital filters for exquisite
tonal accuracy and musicality. The Ayre MP filter provides a significant step ahead in digital audio reproduction. In addition, this exclusive advance in digital audio reproduction is included in the
Ayre QB-9 USB DAC, achieving the most natural and realistic sound available from computer-based audio
systems.Connected via the ubiquitous USB port, the
QB-9DSD generates the master audio clock and
requests the data from the computer at the correct
time for jitter-free playback of your music. Apple
computers can use the standard device driver, while
Windows PCs must install a free download available
from the Ayre website.The QB-9DSD also utilizes opto-couplers to provide
total electrical isolation for the connections between
your computer and music system. This minimizes
the introduction of unwanted radio-frequency
interference (RFI), generated by all computers. The QB-9DSD
will play back DoP files in their native DSD format. 

Buyer pays actual shipping cost and PayPal fees. I get great rates via FedEx so shipping

should be about 30-40 dollars anywhere in the US. No credit cards or checks accepted.