I've had a tube get noisy on my PL-L, I've order the tube kit b/c of the comments above on testing/specs/matching Nagra does.
On the side, I have tried a few other 12ax7's (The TJ Full Music 12ax7's are pretty nice-more detail/bottom end...brings the image forward somewhat). You do get a gain here or there, but seem to loose something here or there also. The stock tubes seem to be just about perfectly balanced on all parameters.
I think the Nagra tube kit is about $250. So if you buy a few 12ax7's doesn't take long to burn through $250 in NOS tubes...and be underwater in comparison...
Let us know what you decide...
On the side, I have tried a few other 12ax7's (The TJ Full Music 12ax7's are pretty nice-more detail/bottom end...brings the image forward somewhat). You do get a gain here or there, but seem to loose something here or there also. The stock tubes seem to be just about perfectly balanced on all parameters.
I think the Nagra tube kit is about $250. So if you buy a few 12ax7's doesn't take long to burn through $250 in NOS tubes...and be underwater in comparison...
Let us know what you decide...