Jperry,
Short answer- This preamp really needs NOS tubes in the line stage.
I'm presently using what are suppose to be 60's Russian 6sn7's. I could live with these, but I asked Mark at Rogue Audio (how cool is it when the CEO answers the phone!) to send me a quad of Sylvania 6sn7's when they become available, and I'll keep the Russians as backup.
I put 40 hours on a quad of new Sino 6sn7's (long story) but that's all my ears could take. In my system, with mostly not very well recorded material (50's and 60's blues, R&B, and R&R) they sounded...harsh and two dimensional.
The phono board came with what might be Siemens or Phillips 12ax7's (triangle etched in the base at the center between the pins) in the first gain stage, and Sylvania 5963's (or 5814's) in output stage. I suspect that these were the original tubes from the year of manufacture (about 2000).
I checked my tool box (I'm a retired musician) and put in a pair of NIB 70's RCA 12au7's with good results. I also tried a couple NIB Amperex (yellow box made in West Germany)12ax7's in the first stage, but haven't had time for critical listening of that change yet. Those changes did reduce the noise slightly. I also have about six RCA and Japan NIB 12ax7's on hand, but I'm getting pretty tired of playing with tubes, and ready to get this sorted, and start paying attention to the music.
Short answer- This preamp really needs NOS tubes in the line stage.
I'm presently using what are suppose to be 60's Russian 6sn7's. I could live with these, but I asked Mark at Rogue Audio (how cool is it when the CEO answers the phone!) to send me a quad of Sylvania 6sn7's when they become available, and I'll keep the Russians as backup.
I put 40 hours on a quad of new Sino 6sn7's (long story) but that's all my ears could take. In my system, with mostly not very well recorded material (50's and 60's blues, R&B, and R&R) they sounded...harsh and two dimensional.
The phono board came with what might be Siemens or Phillips 12ax7's (triangle etched in the base at the center between the pins) in the first gain stage, and Sylvania 5963's (or 5814's) in output stage. I suspect that these were the original tubes from the year of manufacture (about 2000).
I checked my tool box (I'm a retired musician) and put in a pair of NIB 70's RCA 12au7's with good results. I also tried a couple NIB Amperex (yellow box made in West Germany)12ax7's in the first stage, but haven't had time for critical listening of that change yet. Those changes did reduce the noise slightly. I also have about six RCA and Japan NIB 12ax7's on hand, but I'm getting pretty tired of playing with tubes, and ready to get this sorted, and start paying attention to the music.