Tube rolling Audio Note DACs

I put a pair of new JJ/Tesla E88CC into my 3.1x Balanced, and they did a very nice job - better extension and even more of that wonderful midrange clarity. A pair of NOS Brimars didn't work out as well. I left the rectifier alone.

I have a pair of Siemens CCa in my AN DAC 1,1 sig and they sounds great.

Interesting! I don't have my manual any more since I sold the 2.1x balanced, but thought it interesting that it was in there. Perhaps a different rev. of the manual. Mine was from Fall '03, so perhaps he added the section. Of not, I do still have my old dac 2.1x signature and its manual. The exact quote comes under the section titled "Experimenting with Different Valves" just prior to Warranty and Servicing" and it reads: "The best I have found is the Telefunken E88CC 01 gold pin, expensive, but worth every penny." As I mentioned, the CCa is close but preferable in my system... but it is always interesting to hear equipment the way the designer voiced it.

The TS is a nice rectifier. It is one of my favs for 6x5gt, but I have a slight preference for Mullard and Bendix. At that level, it is just a matter of taste, though.

Still recommend Tele CCas for detail and extension and the Amperex 7308 (JAN or PQs) for richness. Can't compare the two yet since my older PQs have not yet arrived...

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.