Different preamp, but I have the premier 14 and replaced stock 6GK5's with Mullards and the improvement is not subtle. Much sweeter, more bass, richer midrange. The 14 is absolutely quiet with both types of tubes.
CJ Premier 15 & 17LS Tube Suggestions
I have been using a conrad-johnson premier 15 phono preamp for about 18 months and just purchased the premier 17LS preamp six months ago. I am very happy with this pair except for what I consider to be excessive tube noise from the stock tubes. With the 17LS set to mid-range (50 on the display), I hear, what I think is excessive tube noise for units at this price range. I haven't had time yet to experiment (too much travel) with different tubes. I am looking for suggestions for low noise tubes (and sources of tubes) that would improve upon the stock tubes I am currently using. Any suggestions for different brands of tubes and where I can get them would be greatly appreciated. Thanks in advance for the help!