12ax7 vs 5751

i did some rolling to and forth between the ei elites and the telefunkens today. there really isn`t much if anything between them. the telefunkens definately have a wider soundstage. the sound seems to go beyond the speakers which i really like but in pretty much all other area`s i couldn`t really tell the difference. the ei elites, one side is slightly microphonic but again it doesn`t really effect the sound performance at all.

i have my pioneer bluray player plumbed into the amplifier and watched shrek earlier. the sound was really good. music scores in the film sound excellent and voices throughout the film sound very natural. of course there`s no explosions or the like in this film so i can`t comment on stuff like that plus i have to think of the neighbours! music on this film certainly has some punch though!

by the way i`m from the uk and had our first snow fall today! i`m praying it stays for at least some of the week so i don`t have to go to work lol more listening time for me hopefully!

describe microphonic

Mcpherson,

No worries, it's certainly not a silly question. I'm not confident that I can answer your question about the brightness of your system to total certainty, but I can perhaps explain my earlier comments a little more clearly.

I want to make sure that my comment about the slight smearing is in the proper context. I was comparing Telefunken rib plate 12AX7 to Telefunken smooth plate 12AX7 in the signal tube position of my Rogue M180. The driver tubes were held constant with Telefunken rib plate 12AU7. The Telefunken were already my favorite tubes for detail, dynamics, speed, tone, and certainly clarity. The comparison between the smooth and rib plate is really getting down into the small details, I like either one better than anything else I've had in my system, and I could live happily with either of them and never look back.

We were listening to acoustic guitar with the rib plate 12AX7 first, then swapped it out for the smooth plate. After a few moments we realized that a little bit of information had been lost in the sound of the strings in the trailing edge of the notes. At the edges of these notes the rib plate was more convincing, the smooth plate just very slightly fuzzy. But as I mentioned before, I could live happily with the smooth plates.

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. I was on another thread where the discussion included RCA tubes (which I used before moving to Telefunken) and one someone commented that Telefunkens were a little brighter sounding than RCA, so perhaps changing tubes could help you. I moved to Telefunken because I was hearing dynamics and clarity. I've never had to battle brightness in my system, and I made the change too long ago to remember that aspect of the RCA sound. But along those lines, RCA is warmer than Telefunken, and Mullard is warmer than RCA. If the other Audiogon member's comment is indeed correct, then maybe changing tubes could solve the problem of brightness in your system.

You didn't mention anything about the rest of your system other than the Focal speakers - do they have beryllium tweeters?

I asked the guys at the stereo shop today about your questions. Several comments were made, but there wasn't too much discussion, so I'll just relay the comments: (1) Focal are bright sounding speakers, (2) yes, it is possible to reduce brightness with a change in tubes, but they would need to know more about what is in your system, (3) would first be looking at your interconnects or speaker cables, (4) wondered if you had silver cabling in your system as that can sometimes add brightness.

As far as tube microphonics, if you google “tube microphonics” you'll get plenty of hits. But you don't want any microphonic tubes in your system. I had a very microphonic tube in my preamp once and just touching the volume knob was amplified through the speakers.

i have a bus route that goes straight past where i live and the road is uneven a little. when the bus goes over the uneveness my flat shudders! one of the tubes picks this up but its onlt very slight and you have to be pretty close to the speaker to hear it. it`s like the tube is vibrating. i tell you something that helps in this case is using sorbothane feet under the amp but my amplifier is pretty heavy (30 kilo`s) and i think i`ll need to purchase extra sorbothane feet. they`re very cheap and you can get them off ebay. i have them under my cd player and my bluray player too. amazingly they made a difference to the picture on my bluray player. don`t ask me how but the picture is sharper. i thought it was me but everyone thats been around here has noticed the difference too! they helped under my cd player too with the soundstage. it just seems more focused. not bad for a cheap upgrade! if i didn`t have them under the amplifier i`m pretty sure it`d be a nightmare to listen to. not sure if those tube dampers work. i might give them a go unless anyone reading this can advise otherwise.

Mcpherson please feel free to ask any question you wish ok. if i can`t help then i`m very sure others will like reynolds for instance. like you i`m a newbie to tubes aswell so any information is valuable. tubes are expensive enough without making costly mistakes. all the tubes in my amplifier are in there for a reason. i`ve done endless research on each tube as to what their sound characteristics are and kind of gambled buying them. i`ve been very lucky so far in my mixing and matching and each tube i`ve added has enhanced the sound out of my amplifier. my treasure tubes kt88-z`s look like being delayed further now because of this snow as probably will the ge 5751`s aswell :( i`m dying to fit them all in!!!