Tube rolling Audio Note DACs

I've tried these 3 tubes:

Telefunken CCa gold pin
Westinghouse 7308 E188CC gold pin
JJ E88CC

The Telefunken is my favorite. It is clearly better than the JJs with an
even presentation over the frequency spectrum. Very nice midrange, but
I think it's a bit rolled of at the top but i can live with that.

The JJ is fine for a tube that is 1/10th the price of the NOS tubes. Clean
from top to bottom, just not as clear as the NOS tubes.

The Westinghouse had great bass and nice, clean highs, but a recessed
midrange that i could not get over.

Naturally the Telefunkens are the most expensive. This was an
expensive exercise for me, but definitely a good learning experience.
Each tube is different and perhaps none is perfect. This is frustrating in
a way because once you buy the component to get the most out of it you
have to fine tune it with tube choices (but this is of course an advantage
too). Part of me wants to go find a nice SS DAC so i don't have to worry
about tube choices, but the Audio Note DAC is SO DANG GOOD I can't
do that! Everytime I take the cover off the AN to change tubes I'm very
impressed with the clean elegance inside, and the screws are top notch
too. A real winner.

I recently put a pair of NOS Siemens into the 3.1x Bal when one of the JJ's went down. The Siemens sound more musical than the JJ without losing any clarity. Interestingly, in my preamp the Siemens sounded thick in the bass and rolled off on top, and I much preferred a pair of Amperex. The Siemens sound much better in the DAC.

Resurrecting this thread...Anyone rolling tubes more recently in their AN DACs? Interested if anyone swapped the Rectifier tube out for 6x5gt, KenRad. 

It’s hard to beat TungSol 6x5GT in Audio Note components, but I understand the quest.

There’s an excellent Audio Note thread on Steve Hoffman Forums with a solid cadre of AN owners. Tube rolling is often discussed. You might search that thread for folks’ experiences with 6x5GT alternatives.

I have not tried a KenRad rectifier.