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
PS, if your price is right I will pick up Agon fee. I don't quite know how to do that , but I wll find out provided either of you want to sell the Sylvania or GE.
Mikirob, the comment about the GE's was the OP's, not mine (although I agree). I was quoting Grayf in order to explain my recommendation of the Raytheons which I think would be more to his liking. I do have a pair of GE's, but they are not for sale; sorry.
thats fantastic advice guys. going to the bank tomorrow to see if i have enough funds to buy them. the treasure kt88 tubes are breaking in quite nicely. they sounded very upfront when i first fitted them in and they`ve smoothed right out now. they still only have 52 hours on them so they still have a fair way to go yet. and i had more fun this morning with all my neighbours out again! i listened to it quite loudly! amazing sounds!