Any way to reduce pre-amp noise floor?

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.

The 6922 is part of the 6DJ8 family along with the 7308. The 6DJ8 is at the low end, the 6922 is in the middle and the 7308 is the big brother. These tubes vary in their electrical characteristics but that stuff is over my head.

Most people consider them interchangeable and opinions vary on which sounds best in a given preamp, as usual. I would stick with what c-j told you. They probably have a reason for it.

That's the problem with tubes. They can make noise, die prematurely, etc. That's why the engineers came up with transistors. Any tube can cause trouble at any point in its life, but if you buy good tubes it shouldn't be a common problem. It's the price you pay for that nice tube sound.

There are plenty of 6922s to try though. If you want to try vintage tubes, the Amperex, made in Holland or the USA, is a popular choice. If you want current production, check with Jim McShane. Tell him what kind of change you would like to make to the sound of your preamp and see if he can recommend something that would work for you.

Whether you go vintage or current production buy from a reputable dealer. It will save you a lot of time and money. The good dealers are more expensive but their knowledge of tubes is worth the extra they charge. You have to learn quite a bit about tubes before you start buying them off Ebay or you'll end up wasting a lot of money.

There are good sellers here on Audiogon too. I can't vouch for anyone in particular, maybe someone else can.