12AX7 variant as quiet as 12AD7?

[Audiovet]

Relevant perhaps is that with many modern tubes, even some 'specials', I found an almost unacceptable spread in characteristics; occasionally up to 40%! While not directly related to hum, I would not be surprized to find a variation in hum between same numbered tubes, even same brand. I have not had too much experience of that (meaning hum induced noise in ECC83s) but as said. Even if you have found a solution, it is always a good idea to have heaters elevated to about 60V to common. (Not so relevant with d.c. on heaters, as well as may be impractical depending on the heater power supply design.)

 

[peterh]

Per your recommendations, I did get a trio of JJ ECC83s. I can tell you that they are quieter than the 12AD7. While they lack the euphonic qualities of some of the other new production tubes, their tonal balance is hard to fault, and they really seem to get out of the way of the music.

Congrats!
I also observed that most JJ ECC83S are fairly close to spec and with small unit-to-unit differences.

There is such a thing as new production tubes from western democratic countries !

 

[GuyNoir]

Relevant perhaps is that with many modern tubes, even some 'specials', I found an almost unacceptable spread in characteristics; occasionally up to 40%! While not directly related to hum, I would not be surprized to find a variation in hum between same numbered tubes, even same brand.

I know that is one of the reasons many people are reticent to use contemporary tubes. When I was new to the hobby (a few years ago), I bought a quintet of Sovtek 12AX7WA from a reputable dealer, but one of them hummed loudly. Then bought another five Sovtek 12AX7 LPS...again one was a hummer. I didn't know enough at the time to send them back for replacement. I suppose I should have paid for noise screening. I really loved the resissue Tung-Sol that I got recently - they were very lively and dynamic - but all of them were subject to hum. I've also read more than a few times that no current production tubes test stronger than eighty percent. One would think that manufacturers would screen tubes and improve quality control, as I'd be happy to pay a bit more if they were uniformly good.

I would happily fill my gal with NOS Tungsram or EI if had the loot, but for now, at $10.00 a pop for quiet, transparent tubes, JJ has my attention.

 

[GuyNoir]

Well, just to prove that one's sound memory can be shiite, I put an RCA LBP in V1 and some Hitachi 12AX7a in the other positions. Holy hell, that line up positively wiped the floor with the JJ's.