Any way to reduce pre-amp noise floor?

Good luck finding them. They are somewhat rare and expensive. The majority of ones available now are pulls from old tube scopes, and old military test equipment. Remember, noise is a function of not only the s/n ratio of your equipment, but also the sensitivity of your speakers and gain as well.

For NOS the Amperex are my favorite 6922 followed by the Siemens. Supply can only go down and price most likely will keep rising so I'd say get em while you can.

I've been using current production Genalex Gold Lion 6922 in my CJ ART and have been very happy with them. Even though they are Russian, they sound more like the Amperex. The EH (sometimes Sovtek) is what CJ ships with. They are okay but I prefer the above for my tastes.

The JJ's have a nice tone and they are cheap but I'd have one or two get weak on me in short time. I did like them though so I would just buy a few extras with each batch of 10.

But so far the Genalex's are the ones that are doing it for me it tone and longevity. I buy them from Jim McShane at www.mcshanedesign.net.

Sdp6716,

Any tube can hiss or, worse, become microphonic, which sends a high pitched noise through your speakers.

I like vintage tubes myself and believe the expense and chance of getting a bum tube or tubes is worth it.

You can take your chances on Ebay. You will have good and bad experiences there. I see a lot of vintage tubes for sale on Audiogon, sometimes at good prices. Just hit the Tubes link under Accessories on the home page.

You can buy vintage tubes from tube dealers like Jim McShane, Upscale Audio, Tubemonger, Brent Jessee and more. Just google them. That is what I would recommend. You can discuss what kind of sound you are looking for and get recommendations from them and you can also request that the tubes be quiet. They don't need to be phono stage quiet though.

If you are happy with the sound of your current tubes minus the hiss, you can get new current production tubes that are quiet a lot cheaper. Talk to Jim McShane for those.

Thank you all for the info. I spoke with CJ directly and bought a new EH6922.

At the same time I asked about tube rolling with a 7308. They advised against. They said ok to swap but stick with 6922. I thought the 7308 was the same tube. Is this not the case? I definitely don't want to risk damaging my new - in warranty pre-amp.

I also am wondering about how quickly the last tube developed the hiss. It's only 200 hrs old. I've read about the high gain in the ET3. Is it going to go through an expensive vintage tube that quickly??

I have a dbx 3BX dynamic range processor that I have used in the past that can help lower noise floor during quiet passages if needed.

I find its not needed with most good modern gear that is inherently very quiet when working right. Tube pre-amps are more of a challenge in this regard. Good quality tubes in a good pre-amp to start with is needed to keep noise levels low comparable to most SS gear I have found.