12ax7 vs 5751


hi all,
i need some advice. i`m very new to tube amplifiers and i`ve been doing some tube rolling.

i currently have a pair of grant fidelity matched psvane 12ax7t`s in my amp which sound fantastic.

what i`d like to know is which are the better tubes, 12ax7`s or 5751 tubes. i`ve been looking at forums and there are folk out there that say 5751 tubes are better than 12ax7 tubes.

can i have your thoughts on this please and also which are the good 5751`s to go for.

i really like the psvanes but if they can be bettered i`d go for it as my next line up of replacement tubes.

my amp is a yaqin mc100b. the tubes i have installed at the moment are.....
2 x psvane 12ax7t`s
2 x brimar 6sn7gty/cv1988`s
2 x sylvania 6sn7gtb`s
4 x electro harmonix kt88eh`s

many thanks in advance guys.
grayf
No experience with those tubes, but I just put Amperex NOS Bugle Boys12AU7s in my Primaluna Dialogue1 and Wow! Wow! Wow! Just like the old song, "What a Difference a Day Makes," what a difference a tube makes! Huge well- layered sound stage. Tone, timbre, airy, clear, detailed yet sweet, fuller with more weight, I'm really enjoying the overall musicality of these tubes. Now, I must find another pair of these for backup. These replaced RCA Clear Top Side getter which were very good. Also put in Yugoslavian Telefunken 12AX7s, slightly bettered the the Canadian NOS Telefunken 12AX7s rebranded Northern Electric that they replaced.
Mikirob
Sounds good. Hope I have similar results with the 12at7's. After that I am gonna replace the tung-sol 12ax7 with the GE triple mica black plates.
Mikirob,
Amperex made a 12AU7 variant in the early sixties called 7316. When I tell you they do what the other Amperex do only a lot better, believe me. The problem is that a lot of people other than myself really like them and the price is quite high. As if the regular Amperex 12AU7s didn't cost enough already.
@ Grayf and Mcpherson. Shuguang made a 12AX7 a couple of years ago that I actually liked. It was called the 12AX7 C9 or 9th edition it was clean and accurate with a good strong signal, not warm but really very good. Then they stopped making them for some reason and now you can only seem to get the 12AX7 B8. I never understood what happened, but if you can find them (C9s) buy them you'll prolly like them.
hiya guys,

mac i`ve no experience with amperex tubes but let us know how they sound when you get them.

i`m keeping an eye open for the c9`s mechan. i thought i`d found some on ebay but they turned out to be the 12ax7b`s.

does anyone here have any knowledge/experience with mullard M8137`s? i`ve heard great things about these. i`m putting them on my shopping list when i have the money.

meanwhile i`m still enjoying the golden dragons immensely in my amplifier. i had the volume up quite high for a while yesterday. they sound wonderful and detailed. i forgot to mention the bass. the bass is amazing with lots of detail and depth and texture. i don`t feel i`m left wanting for anything.