12BZ7 ///12AX7

Mahlerfan, do you give your tubes time to break in??
It seems like they go in and out of your amp pretty fast.

Try some "used test strong" Telefunken 12ax7 when you get a chance. They’re solid all-rounders, and relatively common on the 2nd hand markets. But favorite 12ax7, by a good margin, has been the Mazda silver/chrome plate. Unfortunately they’re rare and expensive ($350+ a pair), and they have a bit of extra energy up top - so won’t be ideal for systems that need a push towards a relaxed top end.

Also I like those RCA tall black plates pretty well, but think the Mazdas are much better.

@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.