Whats the best and quietest 12AX7 tube

Gedrrym5 gives good advice about Kevin. My experience with Kevin and the (French Mil) Mazda's is excellent as well. If you want the quietest and least expensive new tube, another option is the 12AX7 LP Sovtec. This is the ONLY Sovtec tube I like. It is a remarkable tube and a fraction of the cost of similar sounding NOS tubes. Other choices for an ultimate sounding 12AX7, is the Telefunken smooth plate. Be prepared to pay dearly for Telefunkens, as they are hard to find, and therefore expensive. Tele's are not necessarily the quietest tube around, but noise is more or less important, depending entirely on where it is used in a circuit. For instance, a Telefunken that would not be acceptable as a first stage gain tube in a phono circuit, could be the best tube available in a power supply, even if the noise numbers were not the best among the tubes you are testing.

David, the Sovtek 12AX7 LPS is the spiral version of the LP, some people have reported that after as little as 60 days that particular tube begins the tube rush (noise) you report. The good news is that either version is very cheap (LP or LPS, maybe $7.00?) so you can afford to replace the pair three or four times a year (if absolutely necessary) for about the price of a good dinner. I know that this is not a wonderful piece of advice, but I have the same problem with my phono stage, and I use Sovtek 12AX7 LPS in the first stage, the Madza's in the second stage and Telefunken in the other stages. I find that the first tube (after the cartridge) effects the overall noise level more than stages after it. When I get the "rush" you describe, I can usually replace the first tubes and be back as quiet as possible without replacing the more expensive tubes. And, thank you for your kind words.

David, I don't know if I can help, the comments from Drumsgreg are correct in that you should seek advice from Rogue. They know about their product much better than I. As far as Kevin, his advice is excellent, and he is probably not keen on promising a quieter set of tubes for your unit, when every factor is not under his control (or knowledge). I have found him to be accurate on sound of tubes, and totally honest in presenting product that is exactly what he says it is. The Penta people purchase tubes out in the market and resell them, exactly what Kevin does. The big difference is that Kevin tells you what you are buying, and Penta does not. It is difficult to choose (and later replace) tubes if you are not certain about what you got in the first place. My choice for NOS tubes as a replacement for the Penta 6SN7 would be the RCA black plate (same number) or if you can afford it the 5692 Red base RCA military tube. The 5692 is quieter, more linear and less prone to microphonics (Kevin can discuss with you). As far as the Phillips, I am not impressed with them. For the 12AU7, call Antique or Kevin and try the Amperex 7316, or Telefunken 12AU7. Both of these sound different from each other, both are great tubes, but you must listen. On the noise issue in general, ask Rogue if we are missing something here, is this an issue with many owners? What can they suggest as an approach to help you? I would not be afraid to call them and state your case. They may even offer you tubes to see if they can help you resolve this issue. One thing, the Sovtek 12AX7 tubes are generally very quiet, HOWEVER they do vary, unless someone has selected them for quiet, you could get a dog. I would ask the factory for a set that they are sure is "perfect" and if the problem persists, ask them why. If the issue becomes one of sound quality, the other tubes I have named are all better than what you have by a mile.

I purchased tubes from Ned at Triode as far back as five or six years ago. Yes, Ned does indeed know what he is talking about, but at last discussion, he was unable to provide some of the REALLY rare and hard to find tubes I was purchasing. IE: Telefunken 6922, Genelex KT66, Telefunken 6DJ8. All of these are EXTREMELY hard to find as brand new old stock. In fact, Kevin is the only person I have ever found to have NOS Telefunken 6922 that are the genuine article. If you do not need these tubes, my remarks are a moot point, however my respect for Kevin is in the fact that he has been able to deliver ALL the tubes I want, and at the absolute best quality available.