Tube rolling Audio Note DACs

There was no mention in the manual about tube rolling or recs for such.

Jwaugh, Thanks. The rectifier tube I added was a Tungsol 6X5GT 1957. This is supposed to be a pretty popular tube with AN DAC users. And frankly yes, my system is fun to listen too. I'm glad to be at the point where I am. Some people dis Mcintosh, but I've tried many other brands and in the end you know what i like.

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.