The build is finished and the sound is great.

I will let you know how it sounds once it has run in for a while but at this stage the improvement is quite staggering.

The build was fairly easy though my shaky hands didn’t make soldering to the dac chip outputs very easy

I am now using gilded copper rca’s and solid core mono crystal copper cabling on input and outputs which came from DIY Hi-fi SUPPLY along with the UVOS.

The UVOS, doesn’t come with a tube. After a bit of reading I chose a NOS , JAN , Sylvannia 6922 for $40 including testing for low noise and mircophony from Tube Depot.

I mounted the UVOS on nylon standoffs figuring they would provide a bit more isolation from vibration for the tube than the metal equivalents.

With about 30 hrs of the suggested 50-100hrs for the valve output stage here are some impressions.

It is rather difficult to make concrete conclusions about the performance of this new addition as I keep getting drawn into the music.That it out perfroms the opa627 based opamp output stage is an absolute no brainer and I would therefore recommend that anyone who doesn’t want to go down the transformer output route should seriously consider this as an option , particularly if your current set-up leans towards the clinical.

The sound of my system is now just more listenable and for that matter much more ‘musical’.Pace rhythm and timing are greatly improved but not at the expense of tonality , timbre and dynamics : all of which have improved by a very noticeable margin.

I am now able to play a larger range of discs without wincing so much at the less than stellar recordings.In fact previously unlistenable pop recordings are now fun and the good recordings are imho jaw dropping.

Some other bits: The quality of the board is great : soldering is immaculate , with all the components well spaced.I had a few questions on the board and the supplier replied within minutes with extensive and simply worded explanations.

Even those who bought the encased dac should consider this add-on as it could be easily fabricated into a second box or even mounted atop the original case with some form of protective cover.

Highly recommended .