Most Musical 6NS7 tube for a Preamp?

Out of the 6SN7 preamps above in your price range the deHavilland would be an excellent choice once modified.  How do I know, I have repaired and modified most of them.  In the deHavilland a toridal transformer replaced the original, V-Capacitors were an upgrade and Audio Note resistors were an upgrade, and tube sockets, etc.  The 6SN7 tube was a cheap CBS which sounded the best in that preamp.  I think you can fit a nice remote volume in there if it does not come with one.

As for the 6SN7 tubes (the deHavilland only uses one 6SN7) the NOS Tung-Sol black glass round plates were the most musical I ever heard - don't agree with the tube chart link in one of the posts above.  Did not work as well in the deHavilland as in other preamps, Ken-Rads are very good, RCAs musical but soft sounding, CBS sound excellent especially as they are so cheap.Tried the CN CV-181 and with the correct bias setting they sounded very nice, pretty balanced top to bottom but overall not my favorite.  Tried the Treasure WE 101D tubes and preferred the Full Music much better versus what others have said about them in the past.

Happy Listening.

BK,

What do those upgrades approximately cost parts and labor?

Thanks for tube tips too.

Have you any first hand knowledge of the LTA or Supratek products?

I’m using the Tung-Sol black glass round plates in my Audio Note pre. They are so pleasing to the senses.

Some good info...
http://www.dehavillandhifi.com/6sn7_vt.htm

Get a 6f8g and an adapter. It’ll blow your mind 

Having tried the top thirteen tubes, of this comparison: http://www.dehavillandhifi.com/6sn7_vt.htm, I have to agree, the Tung-Sol, round plate, w/oval mica, is a beautiful, neutral, extended at both ends, with excellent sound stage and precise imaging, tube.      The pair that I now have in my Carys, came out of three NOS pairs (from three different sources), however.     The other four all went intermittently noisy(crackles), after less than a year, each.      However; I’ll never regret the purchases.      They’re that good.      As some surveys mention; It’s good to mix tube iterations, even if the same brand, which retains the strengths of both, while not emphasizing any weaknesses.      I’ve tried everything mentioned (the top thirteen), in various combinations.     In combo, with the T-S, the best were the tall bottle, metal or black based, Sylvania 6SN7W and Ken-Rad (bottom-gettered), from the 40’s and this Sylvania: https://tubeworldexpress.com/products/vt-231-jan-chs-6sn7gt-sylvania-1944-v1?_pos=1&_sid=79a7fa3be&_ss=r, which gives me the best mid-Bass slam, without coloring the Midrange.      Those four tubes, in whatever position, offer the best sound stage, in width and depth, of any tried, in my system, not to mention, REALISM (ie: tone, dynamics, etc).      I’m staying stocked up, on the others, for when I’m out of (or can’t afford) round plates.      If by, "musical", you mean a warm, tubey, sound; try the other top tubes, on the above mentioned survey.      They all have good presentation, but- were a bit too warm, for my taste.      More opinions, which (of course) vary, per system/ear:   https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/    and:  http://digitalaudiodirections.blogspot.com/2012/06/6sn7-tube-comparison-part-1.html   Enjoy your journey!