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

Showing 17 responses by mikirob

As far as your KT88s, also better better brands out there, some warmer than EH.
Second Andr, Joes Tube Lore gives a great summary. I have Sylvania 5751s Gold black plate that made a huge difference in one of my amps; but always trust your own ears.
Joe states all that in his Lore article; but if you are new to tubes it is a good, worthy place to start.
Andr, well stated couldn't agree more; love those Sylvania's, have them in one of my units. Like you, I tube roll them out periodically, for instance, roll in the GE for Neil Young or other guitar stuff...
Joe' Tube Lore basically says what you posted above, no one really disagrees with what you have stated; but for a newby to tubes, Joe is a good starting point in order not to go broke. There are many tube gurus out there, Jim McShane, Kevin Deal at Upscale, Brent Jesse and so forth, consult with the folks who have solid reps, or someone you know and trust to help with advise and to narrow your search. The Tube Store has also been helpful to me, as well as the others mentioned above.
Yes, when you change out the EH KT88s you will get more improvement.
Best of luck in getting the best out of your system.
Congrats, you found that special tube synergy with your system. So many folks never make it.
Grayf, first, I'm happy for you that you are having a good time tube rolling, learning, listening and so forth; but, I have a small piece of advise, be careful where you buy tubes from. For example, on Audiogon there are some excellent tube sellers with stellar reputations and had you bought those KT88s from say, Trelja, Grant Fidelity, Jim McShane or some others, you would have been enjoying them for weeks already, be careful my friend, so far it seems like you have had good luck. In the UK, Watson sells very good tubes among others. Best.
GrayF, yeah, sell me the Slyvania 5751 and GE pair, that way you replenish some of your investment. That is one of the great pleasures of tube rolling, you can usually recoup some of your money if a certain tube doesn't work out.
Thanks for the info GrayF. If you decide to sell the Sylvania give me a shout out. Best!
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.
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.
Mechans,
I have often wondered the same things, hence, never bought from him. I want ongoing communication and if I fast pay desire fast ship...tubes appear to be good, even if top-tier cost. I've scored some real bargains here on the A'Gon.
The Holland tubes are reputed to sound the best. That has been my experiece with 12au7 Bugle Boys.