12ax7 vs 5751

treasure tubes kt88-z

got `em!!! i got them this morning. i fitted them and left them for 20 minutes or so then set the bias. left them another 20 or so minutes then checked the bias again and then to the good stuff! from the off these are an upgrade! very open sounding. i can already hear the top end is extended. my 1st and so far only track i`ve listened to is k.t. tunstall silent sea off the eye to the telescope cd. her closely mic`d voice sounds just incredible and incredibly real! the weight and texture to her voice is just right and mind boggling! she`s right there in front of me. soooo much detail in her voice and the sharp intake of breath you hear in between her lines! i couldn`t help listening to this over and over! the bass is deep, detailed, darker, warmer and textured. acoustic guitars have realistic tone, weight and that zing that acoustic guitars have. you can hear each string being plucked. the noise floor is extremely low on these and the back ground is silent. after installing these, the first thing i noticed was the lack of low level buzz coming from my speakers. if i put my ear up to the speakers i get a just about audible deep hum.

the soundstage is pin point accurate and the seperation of the musicians is very freaky. lots of air between the musicians! the soundstage is less deep but by no means flat. it`s much easier to get that sense that the drums are behind the singer. you also feel you can almost see the performers. you can also hear k.t. tunstals lips close and open as she`s singing and her voice actually sounds like it`s originating from her throat. by the way her voice on this track will leave you needing a cold shower!!!

the most amazing thing here is i have about another 298 hours to go before they`re broken in! and the sound is said to improve! wow! i`m off to do some more listening to my other favourite cd`s. my plan now is to fully break in these tubes then do one last tube roll between all the 12ax7`s and 5751`s before i make my final choice of tubes for this amp and system. so far i have to tell you i`m amazed at this sound coming from my speakers. more to come later today guys. this is just the initial "straight out of the box" review

another update.....

i had the telefunkens in this mix and and the sound was amazing, extremely clear, forward, immediate, weighty with a hint of warmth, pretty much like someones turned the main light on and you can see everything clearly and solidly.

well i had an idea. i don`t mean to tube roll this early on in the experiment but i read somewhere that the psvane 12ax7-t`s have a synergy with the kt88-z`s, so i swapped them out. in went the grant fidelity matched 12ax7`s. now it`s like someone switched off the main lights, lit several candles so you can still see all the detail but with more shading and more darkness in between, then lit a log fire! WOW! on a seduction level i`d score this mix as a 20 out of 10!!! you get all the detail but accompanied by the sexiest warmth ever! the forwardness has gone and replaced by naturalness with a sexy warmth. the bass is deep, detailed, punchy, slammy when needed, textured and all accompanied by a sexy warmth. voices are just plain sexy!!! the highs are sweet and clear and extended. the bottom end is extended too and accurate. it`s accurate all the way through the frequencies. there`s an amazing dark pleasing background that allows instruments to work their magic on you out of thin air. seperation in the soundstage is 1st class. all this with not quite 5 hours on the tubes! i`m in lurve already and i think i still have heaven to come! these tubes work extremely well together and so far it`s a matter of taste between the psvanes and telefunkens. but saying that, there`s a very long way to go and all tubes are going to get their chance to do their thing once the kt88`s are fully broken in but the psvane 12ax7-t`s will be staying in for the duration of the break in. this is a jaw dropping set of tubes gracing my amplifier so far!

Second the Phillips Miniwatt 12ax7 recommendation. Very good tube in my phono pre. A little brighter and more aggressive than my Teles, but not thin like some others, and with good body.

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!