2. amps-preamps
  3. 1253223387

Do tubes need break in / burn in?

I've bought a set of NOS JAN Philips 5751 tubes to replace JJ 12AX7 in my preamp. After the change, the sound has become worse. The soundstage depth is flat, and just less involving overall. Do the tubes need break in, and if so how long do I need to burn them in?
jylee
thorman
1,262 posts
 
Some equipment just do not respond well to 5751 tubes..It may well only be that case...Try a pair of Amperex Bugle Boys or Phillips Miniwatt 12ax7 tubes and you should be very happy.I have tried a few 5751 myself and always come back 12ax7's...Amperex,Phillips Miniwatt or Tungsram...
hifitime
715 posts
 
I agree with Cyclonicman.It's a different tube.Conrad Johnson
uses 5751's in some of their amp's,but they're designed for
for it.If your amp calls for a 5751,its a different story.Your
VTL 5.5 calls for 12ax7's I think.It should deserve some good
NOS 12ax7's though.I've had noisy JJ's that didn't get along
with some preamps too.Someone suggested RCA's.Bugle Boy's
sound nice at times too.
tpreaves's avatar
tpreaves
2,687 posts
 
I tried 5751's in my Rogue Audio Tempest and did not care for them.I used some NOS Sylvania and RCA 12ax7's with real good success.I then tried a set of Amperex 7025.They sound great and have taken up permanent residence in the Tempest.The music sounds more "real" to me,and isn't that what it's all about.They may or may not work for you.Give them a try,you might be pleasantly surprised.
More to discover