12ax7 vs 5751

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

Ohnwy, yes I have tried (own) 7025's. They can be very good. I particularly liked the Raytheons. Having said that, and with all due respect to some of the comments above, there is no way that one can make a general comment about the superiority or inferiority of a particular 12ax7 variant without making it in the context of a particular circuit. My phono pre uses 12ax7's. I have tried (own) just about every NOS brand and variant of 12ax7, and as was the case after similar experimentation with various tube types in other pre's and amplifiers my conclusion was:

There are specific brand 5751's that can be magic in a particular circuit compared to all other 12ax7's or 7025's; and vise versa. In the case of my current phono pre, while some variants can sound very good (Raytheon 7025, Sylvania Gold 5751, and even the very rare CBS industrial 7729), when all is said and done, the best FOR ME and IN MY PRE are the Telefunken smooth plate 12ax7's; hands down.

In all my years of playing around with tubes I have heard nothing that definitively tells me that (for example) ALL 5751's sound better than all 12ax7's, or 7025's, etc, in a particular piece. IMO.