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Rolled some 12ax7's recently...

Hi All,
I went through my supply of 12ax7's recently and found some goodies.
I recently compared Bugle Boys to Telefunkens in the phono stage of my pre-amp. Interesting (to me, at least). I found the Telefunkens to be nice sounding; very clean and clear, very nice detail, over all a very nice sounding tube. The Bugle Boys, however, were magical! WOW! Timbre was so much more apparent. The soundstage depth and width increased; especially the depth. The music seemed to come alive and glow. It was much more captivating.
I found such a dramatic difference between two high quality tubes very interesting.
I have yet to try 10m's, and 70's Mullards that I found. I will report when I do...
By the way, NOS Sylvania's sound nice in the line-level stage. All tubes reported are vintage NOS. I match them with my tube tester. And, I do not change the volume setting between tube brands tested.
Any comments are more than welcomed! I appreciate any information on your experiences with 12ax7's. The price of some of these NOS is incredible; I am glad to have these nice examples in my collection!
Cheers.
bicycle_man
nsgarch's avatar
nsgarch
2,517 posts
 
Magnum, the reason audio people like the 5751 (or European 'CV' military) version of the 12AX7 is because they have been 'ruggedized' for military use -- which (as a byproduct) makes them free of detectable microphonics, especially the ones with the 3-mica construction. This is more or less important in audio depending on the application -- phono and microphone preamps being the most critical.

The fact that 5751's (generally) have a smoother presentation is just icing on the cake.
.
fishboat
245 posts
 
Abuck,

If you're looking for THE 5751 to put in your JD100 look for Raytheon 5751's...if you can find them. They won't be cheap, but I found them to be better than the GE blackplates and many of the other common 5751s.

Actually Amperex orange globes sound very nice the the JD100..the globes will be a reasonable-bit cheaper that BB and they sound the same to me. Make sure the Amperex tubes are made in Holland.

Never messed with TF's. I read something a while back that there were lots of fake TF's out there...or at least some made in West Germany vs East Germany & the East versions (TONS of them around) were sub-par vs those from the west...? Can't remember.
abucktwoeighty's avatar
abucktwoeighty
1,034 posts
 
Thanks Fishboat. I just purchased a pair of Sylvania JHS 5751 WA black plate triple mica's to try. These weren't inexpensive either!
fishboat
245 posts
 
abuck...yah..I have some of those. They get good reviews in various places on the web & they are good. Whether they are better than the others I mentioned depends on how each sounds in your system. Every setup is unique in many respects.
magnumpi205
504 posts
 
Ruggedized means stronger not better. All tubes should be checked for microphonics on an individual basis.
That would be like saying Queen Latifah is a better singer than Beyonce because she outways her by 100lbs.
Rugged makes a Marine not an opera singer.
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