Audio note Dac question

Here is a review I wrote of the PWT

http://forum.audiogon.com/cgi-bin/fr.pl?rdgtl&1267420882

As far as upgrades go - I briefly reviewed the AN Kit site for a refreshment and would definitely start, at least, with the 2.1 B kit - the I/V transformers are a crucial link in natural digital conversion, in my opinion. I did not notice if the "signature digital board" is included or not with the 2.1 B but if not should be done. Next, if you can find a AD 1865 N-K chip, that is a surprisingly cheap upgrade - I remember I found mine at an online electronics distributor for $50 - they can be hard to find though. I am also a big fan of the open, crisp, natural, unavailing V-Caps have on sound, they are pricy but I recommend when you want to spend a bit more.
Cheers

Also, I agree with Charles1dad, the PWT is definitely natural and transparent... On another note, I have not had personal experience with the 47 Labs Flatfish but have been recommended towards it by several folks for it's naturalness - I have also heard it can be a bit finicky though (and the reason I have not tried)...

On another inspection of the kit web site, I see the 2.1 kit can be had in 12AU7 drivers instead of the 6922 - this may be of interest. I use 12AU7 Mullard “long plate square getter” in my MP3 preamp and love them, plus I believe 12AU7 are more competitively priced than comparable 6922 tubes - anyway, my 2 cent

My DAC board uses 5687 drive tubes (kit 2.1 c / 3.1 +) and I use 7119 Amperex lovingly.

Thanks Grateful for all the info.