12ax7 vs 5751

Another thing about the 5751s is that they were designed for the military, so they are very rugged, long-lived, and low in noise. I had the great fortune of picking up a pair of NOS Sylvania Gold 5751s about 14 yrs ago and they now reside happily in my Jolida phono preamp.

another quick update and the best one yet! when i was tube rolling i tried the brimars and the rca vt231 together. i had the brimars in v1 and v4 and the rca`s in v2 and v3 on my amp. they sounded pretty awful! well i didnt realise that swapping them around would bring a massive difference! this weekend i put the brimars in v2 and v3 and i put the rca`s in v1 and v4. wow the sound is so clear!!! i wish i discovered this when i first tried them. i`ve lost the warmth i had with the brimar/sylvania pairing but now i can see much further into recordings. all the subtle sounds that were hardly noticable are now much more prominent. recordings are very clear sounding and tonally more realistic. the soundstage is solid and believable. the detail is amazing! the bass is very full, detailed and has this extra punch. my amp sounds completely different now! i can`t believe how much clearer the overall sound is. i heard the most subtle details that i`ve never heard before on david gilmours cd on an island this weekend just gone and the sound effects throughout his cd are just incredible! listening to adeles cd 21 the 1st 2 tracks now have so much drive. the seperation of individuals is just awesome too. i could still do with more depth to the soundstage though. i really am sure it`s the psvanes restricting the depth of the soundstage but i must say, changing the brimars and rca`s around have hugely widened the soundstage though. for the first time the sound goes way beyond the width of the speakers which i have to admit messed with my head at first! anyone that has this amp really ought to try out the brimar/ rca vt231 combination. this is seriously good stuff!

As far as your KT88s, also better better brands out there, some warmer than EH.

hiya mikirob, i`ve had those on my mind too! i`ve liked the ehkt88`s in there but when i bought them i`d only done limited research into all the tubes. i`m doing a much more in depth research now. i ordered a matched pair of ge5751 black plate d getter 1950`s tubes today. once they`re sorted i`ll start researching the kt88`s. i wont rush my research like i did when i first got the amp. this has been such a fantastic learning curve researching all these tubes and reading other peoples experiences with different tubes. i still can`t get over the differences made by swapping the brimar/rca vt231 combination. i honestly didn`t think there`d be any difference at all by swapping them around in v1 v2 v3 v4 positions. that was an eye opener for me! all my neighbours were out earlier today so i was able to crank the volume up! i`m endlessly impressed by what i hear now. the only thing i think this amp lacks now is soundstage depth and i`d like to inject a little warmth into it. not much just a little.

i ordered a pair of ge5751wa black plate d getter tubes and a matched quad set of shuguang black treasure kt88-z`s. the ge`s are coming from china and the black treasure are coming from hong kong so i guess i`ll have a bit of a wait.

i`m excited to know how these will fair along with the brimar 6sn7gty cv1988/rca vt231`s combination. the brimar/vt231 combination have so far opened up the sound extremely on my system. at some point in the future i`ll be ordering the Sylvania JHS 5751WA Gold Label triple mica blackplates but i`ll have to start saving! i`ll also see how i get on with the ge5751wa`s first.

meantime, the sound is still improving on my system so i guess the brimars are still breaking in as they are nos tubes. i still can`t get over the huge difference they`ve made in my system. i`ll update next when the tubes i`ve ordered arrive. the only thing i`m not that thrilled about is the break in time for the black treasures. 300 hours!!! they`ll take forever!!!