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
Mcpherson,
Thor has a very very good reputation. If you can get the British tubes into the pre it will make an obvious improvement. I happen to use a highly Modded AE-3 by AES a sub brand of Cary. It is a simple pre which uses 6SN7s, they have great, mellow tone, and are highly linear. It doesn't hurt that I put some very fine, metal base Sylvania 6SN7 "Ws" in it. Thor power amps use EL 34s and would appear to be a really good choice. I have a variant of EL-34s in my power amps, the tetrode 6CA7 fat bottle by EH, which sound really big and powerful. My amps, BTW, are Opera Consonance Cyber 800 monoblocks. The inputs tubes are OS Tung Sol 5687s and Mullard 2493s a 6922 variant. My speaker cables are Jena Labs entry level, which are an all copper braid. The combination is magical.
I have 2 pairs of 5751 RCA and Sylvania, all test very good. I think they are RCA Triple Mica Black Plate, from 1960's.How much do they go for.
I just bought a pair of Rca 5751 triple mica black plates for 70usd. It's my single input tube and I love it. I've read the Sylvania's are supposed to as good but I have no experience with them.
I have Tung-Sol long plate 5751's, GE triple mica black and grey plates, Sylvania gold 3-mica grey plate, 2 mica RCA black plates, and more, but the only 5751/12AX7 slots I have are in my driver board on my power amp. I find that some of the lesser tubes can sound a little stuffy, but all of these that I listed sound pretty damn good. The Tung-Sols seem to be the cheapest (when you can find them), so that's what I use regularly. My driver board is also designed for 5751's; I've found that 12AX7's just don't sound as good in the circuit. I did enjoy 5751's in place of 12AX7's in the guitar amps I used in the past.

Grayf - I got a quad of the treasures in the mail two days ago. I think they sound as good as my NOS Siemens, Svetlanas, and RCA branded mullards fresh out of the box (and apparently there's about a 400 hour break-in window). I think you'll enjoy them.
hi all

i did some extended listening yesterday evening at a much more decent sound level. i found the ge 5751`s a little too warm for my set up. all the detail is there just too warm. my amp is already on the warm side so i guess the ge`s were too much for it. they`re a little noisy too with pops and crackles coming out of the speakers until they`ve warmed up so i`m definately sticking to the telefunkens for now. i will try them again once i get the treasure kt88`s and all the other tubes to see what gives me the best sound.

Mcpherson the k.t. tunstall cd is a very very good recording indeed. it`s the best cd i`ve heard so far and thats saying something! i thought dave gilmours cd was good if not the best but k.t. tunstalls is even better! when i get the treasure kt88`s i`ll have another listen to the ge 5751`s and if they`re still not suitable we can do a deal if you like ok. i got them for $60 but because they`re a little noisy i won`t be asking the same as what i bought them for so at least you`ll be able to see if they`re more suited to your set up without breaking the bank. i thought about your set up when i was listening to them yesterday evening. my amps just too warm to get the magic out of the ge`s.

talking of those kt88 treasure tubes i can`t wait to get them. not looking forward to the lengthy breaking in though but i`m sure they`ll be fun all the same. i`ll do a more in depth review of them too when i first install them right the way through to be broken in. there`s reviews out there for them but nothing much in the way of in depth reviews, so keep dropping by on this thread there`s much more to come guys!
Dear Reynolds853:

I think the rib plates have a smooth sound, which to me means the sound isn't edgy. I just think rib plates provide a little more musical information around the edges of notes than the smooth.

This has also been my experience with Telefunken ribbed v. smooth. I also find the ribbed to be a bit punchier. I prefer them.

Best,
Bill