Low Noise Tube Suggestions

I recently swapped a solid state DAC (Muse 296) for a tubed unit (Lector Digi 2.24). I really like the sound now, but there is a little too much tube hiss. I find it distracting in between tracks or during very low passages. The Lector (and the Muse before) feed Audio Mirror SET tube amps directly (no additional preamp). With the Muse it was absolutely quiet, but with the Lector there is significant tube hiss. The gain of the Lector DAC is quite a bit higher than the Muse (3v vs. 1v).

Can anyone suggest some very low noise tubes to use in the Lector DAC? The previous owner provided two sets (CVC ECC81 and Fender 12AT7) but both sets are too hissy. I would also if possible prefer a set with somewhat lower gain. NOS tubes maybe?

Thanks in advance.
The Telefunken ECC801S and Siemens ECC81 tubes were built and specially selected(low noise) for the German Telephone Service. Most 6201 tubes are also built with extra mica and other low-noise features. I've got a NOS matched pair of 6201's that I could send you to try in your system(free). Whatever you go with: Be certain they are certified "Low Noise."
Hi Rodman,

Are 6201 tubes direct replacements for 12AT7's? I had not heard of them before. What companies manufactured them?

How would you compare the Telefunken's and Siemens to the RCA's as far as noise and other characteristics?

- Stew
The critical element is buying tubes from a dealer who checks out the noise level. Kevin Deal has a platinum or Phono level grade. Jim McShane on AA is very careful about tube noise.
BTW 6201 are a ruggedized drop in for 12AT7s don't be afraid to try them.
Hi Stew- As Mr M stated: 6201's are drop ins, and actually just another designation of the 12AT7 family as are the ECC801S, ECC81, CV4024, etc. Yes- Upscale Audio is an excellent place to shop for top quality tubes(I've purchased my output tubes from him for years). Here's a page with some info on the family: (http://www.audiotubes.com/12at7.htm)
Give Andy Bauman/Vintage Tube Service a call.His pricing is reasonable.He carries three grades of tubes-line/MM/MC.His MC graded tubes have been extremely quiet and dependable.
Thanks folks. I ended up buying a set of RCA NOS tubes through Vintage Tube Services. I had bought some stuff from Andy in the past, so felt comfortable with his suggestion.