12BZ7 ///12AX7

@lowrider57 I responded to the Q concering so called ~~Burn In Theory~~ over at my New Kids topic.
There i completely expose that scam and believe my comment is 
verifible , believebale, honest, fair, unbiased.
I put the final, last nail in 
~~The  Snakeoil Coffin* once and for all.
 @ Mulveling
Someone here on audiogon mentioned in a  post, he has tried Teles and Siemens , the Teles he found more on the ~~warm~~~ side, vs the highly detailed Siemens. 
I always go for clean/clean/details. 
I have Siemens AX's / RCA AX's /tall blacks, arriving this week. 
Look or a YT vid upload , late sunday night. 
The Mazada's , chome plates, , I recall havinga  pair, i did not like them at all.

My system now with new added silver sterling to speakerwires (16 individual wires total, = biwire 1 copper + 1 sterling 14 ga silver  = 2 X 8 = 16 insul wires,,,
and the wires are correctly employed = no criss crossing .
+ took out the E188's in the Lite LS9 Jadis clone pre and installed tyhe stock EH 12AT7's and that as well made a futher gain in details, but is more *beefier* sound, not as laid back/quiet,  as the E188's. Prefer the AT's overall. and so the AT's will remain.
My system has made some progess, and will report back on futher mods/critque.
Our goal here is to finda  path to Pure Class A resolution/highest fidelity. 
3 things , no 4 things are required
1) Patience
2) reserachreserachresearch
3) trial and error
4) $$$$$$$$

The Tele ribbed plates aren't as warm as the smooth plates - you may like those better. Surprised you didn't like the Mazdas, but systems change and optimal tube selections can change over time - are you sure they weren't the 5751 silver plates? Those were awful lol. 

Yes 5751, horrible, 
I am bidding on  a pair of Tele, 16 hrs left,,I am winning at $81,,,tubes pulled from a  estate sale, working ociliscope, look NOS 100%, I am at top $, doubt i win. 
Might try in 2 yrs to pick upa  pair.

I have tried Mazda 12AX7( S) silver plate with Sylvania 12BH7(A) in my Rogue Apollo’s upgraded to Darks at factory, actually on Mulveling’s recommendation. I am very pleased with the results. Currently, I am using  Mazda 5751 silver plate 3mica and like them. They sound more revealing, albeit not as quiet as the silver plate 12AX7S. I understand it’s a matter of personal taste, but am I missing something here?

@chinacat
The 5751 silver plates, as you mentioned, are very revealing. However in my system it was revealing to the point of being BRUTAL. Including an excess of high frequency energy. I liked the effect for up to 30 minutes at a time, but then it became too fatiguing to continue. The 12ax7 had the better, more natural balance. However the 5751 was very exciting at first, especially with certain recordings.

Then, of course every system and set of ears is different! To add some context, my Tannoy Canterbury GR speakers often don’t do well with upstream gear having any excess treble energy. I am glad you enjoy the tubes, regardless!