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
I have tried 7025s only briefly. I found them to lack the delicacy transparency and detail the 5751s gave me. I didn't try many because they seem to be a favorite of the Guitar amp guys who drive up price and make good ones quite scarce. I know I tried RCA but don't recall others. The major differences in Telefunkens are smooth vs ribbed plate and early vs later. Also the holy grail of 12AX7s is the ECC803S by TFKN. I own some 802 and 801S but sadly never lucked into or afforded the 803S.The early smooth plate 12AX7s seem to be the preferred tube but not by everyone.
ok the telefunkens i have are the ecc83 smooth long plates with halo getters. no idea what year they are and they have the diamond stamp underneath. i did look into those ecc803s but they were pretty much out of my price range, but yes i`ve read that they are the best ones to go for, but i think the telefunken ecc83 are more than good enough. the ecc803s are much harder to find too. there`s a pair on ebay i`m watching just to see how much they go for. the difference in sound from the smooth plates and ribbed plates are supposed to be.....smooth plates = accurate sounding, ribbed plates = warm sounding. i opted for the smooth plates because the black treasure kt88-z`s that i have on order are warm sounding and i don`t want an overly warm sound from my amplifier. the sound i`m getting at the moment is accurate with a hint of warmth which i`m loving.

i had more of a listen earlier. listened to adele and also steve hillage "green". adeles voice sounds very natural. her voice has a natural dryness which the telefunkens preserve perfectly and some of her tracks have amazing bass drive. those tracks are extremely pleasing to listen too as i`m sure my neighbours can vouch for the bass!!!

listening to steve hillages green cd is just amazing. the highs are so extended. more so than the ei elites! there`s only one track on green that i don`t really like that much (too hippyish lol) but at the end of the track the last 30 to 40 seconds there are some mindblowing high frequency sounds, well these telefunkens produce these highs with such beauty and accuracy. it literally makes your eyes widen in sheer surprise and awe! these high frequency synthesiser notes hang amazingly in the soundstage and actually move around and these tubes make it so easy to follow. i think magical is the word i`m looking for.

onto dave gilmours cd on an island. on this disc he wrote a song called smile, a very poignant song about loved ones lost. without going into it i lost family members between 2005 and 2007 as well as having to have my dog put to sleep. these tubes bring out all the emotion and i couldn`t help but blub big time! this is probably the most beautiful track i know on any cd with beautiful lyrics that will help anyone who`s been bereaved come to terms with their lost ones. thank you mr gilmour for that! my favourite track on this cd is the very last track called "where we start", and oh my god the guitar tones are just so seductive now and to die for!!! i just cannot stop listening to this track and i bet the neighbours know every last second of this track lol. the sound effects all the way through this cd are just so clever and amazing to listen to. i recommend this cd to all. i think it`s his best work ever but thats my opinion and i must admit i have emotional ties to this cd.

in a way, as much fun as this has been with tube rolling i`m so looking forward to concentrating on the music. thats not far away now. i am a little wound up with the length of time i`ve had to wait for the ge 5751`s and the black treasure kt88-z`s but i`m sure the wait will be worth it. (i gotta learn to be patient lol)

the ecc83`s that i have here are more than good enough!
god there`s always something i fotget to add which is always important too lol. the noise floor. it`s lower on these tubes than the ei elites which is low enough as it is. it makes for a super impressive listen. hard to describe too. it`s like notes are produced from darkness. this is an aspect that i just love. it`s also the very reason i`ve ordered the black treasure kt88-z`s. these are supposed to have that in spades! another reason why i`m wound up with all the waiting lol. i did warn my postman earlier when signing for the telefunkens lol. told him not to deliver anymore post unless he has my parcels lol. he thinks i was joking!!! muwaaaah ha ha ha lol
a quickie update, i contacted the shop in hong kong about my kt88-z`s. they should be here next tuesday. customs have my tubes and have just released them. they had them ages too grrrr! no sign of my ge 5751`s though but to be fair it states in their advert it`ll take 20 to 25 days so hopefully they`ll be here next week too
I have not read every post in this thread, so I will apologize ahead of time if I am repeating any previous comments.

I have Rogue M180 monoblocks that for a year or so I used with Silverline SR17.5 bookshelf speakers. I used the 5751 with them and it was great. I eventually acquired some Silverline Bolero floorstanding speakers and the 5751 didn't work well with them at all. The sound was just, well, blah. I replaced the 5751 with a Telefunken rib plate 12AX7 and the system was dramatically improved. With that substitution the tube compliment in my amps was Telefunken rib plate in the 12AX7 signal tube position, RCA 12AU7 tubes in the driver position. I have since replaced the RCAs with Telefunken rib plate 12AU7s.

I also have a pair of Telefunken smooth plate 12AX7s. I put them in the signal tube position and both me and a buddy noticed that the leading and trailing edges of transients were slightly smeared compared to the rib plate. I prefer Telefunken to all other tubes I have auditioned and/or used in my system (the others being RCA, Tung Sol, Amperex). But to me the smooth plate Telefunken is slightly warmer than the rib plate. Both are very, very clear, but I preferred the dynamics and crispness of the rib plate, and once they break in, mine were NOS, they are actually quite sweet. Smooth, clear, dynamic, fast.

Also, in my headphone amp I have a smooth plate 12AX7 and smooth plate EL84s, but I plan to replace the 12AX7 with a rib plate - it's on order and should be here soon. We'll see how that goes, in that application the smooth plate may be the ticket!

Anyway, back to the original question, I think the 5751 is a great tube, but I've been very happy since moving on to the Telefunkens.