12ax7 vs 5751

Grayf,

Are your 12AX7 Telefunkens ribbed or smooth plates? Also, if they are new old stock, I found that after around 30 hours or so my Telefunkens started to break in and added a nice sweetness to the sound.

I made the switch to tubes about three years ago. I am fortunate that I frequent a stereo shop here in town that has been around since 1947. I'm friends with the owners and they let me bring home all sorts of tubes to audition. It really is great how the sound of a system can be tailored, and you are doing what it takes to do that with your system. And please keep your updates coming. I enjoyed the process of dialing-in my system and it'll be interesting to see where you take your system.

hiya reynolds,

unfortunately the telefunkens are seconds so i guess they`re broken in plus i have about 50 hours on them. they are the smooth plates. i wish there was someone local to me to get tubes off or to swap. i`ll break in the kt88`s then do some proper evaluations of all the 12ax7`s and 5751`s. i`m really excited at that prospect! i only swapped the telefunkens yesterday because everything sounded a little too forward for my ears. i`m very sure the changes will be a plenty before the kt88`s are broken in.

things have changed quite dramatically since yesterday with the kt88`s aswell. everything sounds a lot more solid all round. the sound seems darker with very deep bass. voices also seem to have created more atmosphere too and are even clearer. there`s a ton of detail too. the soundstage is very large and very solid. the best imaging i`ve heard yet. if they stayed sounding the same as they are now i`ll be a happy man but i`m currently on just 28 hours so there`s still quite a journey with these to come. i`m loving the bass i`m hearing! i`m hoping i`ll have about 150+ hours on them by next sunday. it`s funny but i keep thinking the sound couldn`t possibly get any better and then it goes and gets better! amazing! the worst i`ve heard these kt88-z`s was last night. voices sounded a little shut in but that didn`t make them sound bad though. they sound very open today. some of the sounds i`ve heard are also hard to describe aswell. i told my friend the kt88`s turned up yesterday and he`s straining at the leesh to come around for a listen but i`ve told him to wait a couple of weeks. he had a cheap valve amplifier many many years ago and loved it. i think i`ve stirred his passion up again!

i just had a rare stroke of luck! it`s sunday evening here, and all my neighbours are out! i put on dave gilmours cd on an island and played it above my normal listening levels and as a real bonus, for the whole of the cd not even a car drove past let alone a bus! how amazing are these kt88-z`s!!! i`ve just been blown away by them! the bass is tremendous and so beautifully rounded. on one track ("take a breath") the bass growled. the atmosphere on each song is amazing! the tones dave gilmour gets out of his guitars are pure magic. my favourite tracks on this cd are the last 3 tracks "smile" "a pocket full of stones" and "where we start" are in a different league through these tubes. closely mic`d voices through this system are scarily real!!! on "a pocket full of stones", the start of the track is just gilmours voice accompanied by a piano, this sounds truly haunting now. incredible amounts of atmosphere and emotion and he sounds so isolated. his voice fills the soundstage and you can pin point the location of his voice. on the last track "where we start" his guitar has a smooth warm feel and he has that amazing ability on certain notes where needed to get that sheen that hits the spot with all of us and these kt88`s pull that off with such ease. there`s not only massive amounts of information on a disc that these tubes can extract but also massive amounts of information within the notes being played themselves. you seem to get it all, texture and tone!

on saturday i likened listening to these tubes to having the main lights off, candles on with a warm fire glowing, well i stand by that even more so now. it`s like watching a dark scene on a bluray disc through a stunning television being able to pick out all of the pleasing brighter detail while still being able to see all the various darker details and shades with the greatest of ease. these are remarkable tubes, and to think they`re only 35 hours old!!! how much better are these gonna get???!!!

need some advice. there`s a pair of SYLVANIA JHS 5751 BLACK PLATE TUBES triple mica square getters for sale fairly cheap. are these good tubes to fo for? they don`t have gold pins, just normal ones. thanks guys

Yes, those are good tubes I'd snap them up if I were you. That being said, you seem to prefer the 12AX7's to the 5751 in your setup (though that might change when your Treasures have completely broken in). If you get them and decide you still prefer the TF's, you'll be able to find someone to take them off your hands (I would).