Best small signal tube for a preamp?

Hi Keshiri, I still don't have the "feel" of the Zoe, and honestly have not paid too much attention to where the volume knob is set. It is a very nice preamp, and an absolute steal for the price, and I compared it head to head with the Vibe/Pulse. Interesting about the black plates, I have a special pair of them (blessed by monks or something) from Brian at AAudio in my CD player and they sound great. This pair in the Zoe was originally a little noisy in the CD player, but are absolutely quiet in the preamp. Maybe they were not seated properly in the player. I have only used the AT7's and the original 6922's in the preamp, but it seemed the 6922's had a bit more drive, and the AT7's are a bit richer and sweeter sounding.

Another pair to look at might be either a GE or Silvania 5751 or 5814. Would be interested in your take on one of these tubes.

After some more testing, I've found the Siemens ECC81 (12AT7) lacked some bass punch with most jazz & rock, and compressed at normal to higher volume levels. As you'd suggested, it may be due to lack of gain with 12AT7 in the ZOE. I put back the 6H30 but it was the same story: too much weight, not much detail, and very noisy. I'm now trying Mullard's ECC88, which is same family as 6922. It's similar to their 12AU7 but more space and midrange resolution, and the gain seems right: I don't need to turn the volume up more than half way.
This leads me to believe that 12AU7 and the 6922 family work best in the ZOE, as their gains seem right in my setup. I'm curious to hear how the Amperex 6922 sounds in this pre, so please do let us know. It seems the US-produced white-labeled PQ is the one audiophiles all over are after.
BTW, my system:
Wadia 830cdp
Technics 1200 tt
Plinius SA100MK3 power amp
Reference 3A Veena speakers

If you haven't heard the Siemens CCa from the '60s(grey plate under getter support),: you haven't heard all the music. The entry price is steep(I had to find three NOS, matched pairs for my BAT VK-D5), but worth every dime. I've had a wide variety of the 6922 family in my ARC pre-amps, California Audio Labs Sigma and Delta DACs, etc. and nothing has come close to the musical realism of this tube. If you are looking for "tube sound", "warmth", euphonics, or sugar coating: don't waste your money. All you'll get through this tube is the pure unadulterated signal.

Rodman99999, I'd love to hear those Siemens in my Cal Sigma/Delta. But, don't they use 12AX7a? :-)

I use 6h23EB's in my BAT (original version - no upsampling). Do you think there is a significant improvement over these when using the Sieman's you mentioned?.

Do you think these Siemens are rugged enuf for an ARC SP10?

Thanks........