How about 12SJ7?

[Ryan Chang]

I just found a vendor who has 12SJ7 tubes with pre-amp schematic. He
says
that 12SJ7 is for military use and has good sound. Should I believe him?
What' are the advantage and disadvantage of 12SJ7?

[Vernon Brown]

The 12SJ7 is a 12v filament version of the 6SJ7. I wouldn't want to us a
pentode in a preamp. All those electrons bouncing off of the screen and
suppressor grids make too much noise for a low level amp.

[Marc Stager]

Vernon Brown wrote:
>
> <skyfla...@bbs.ntu.edu.tw> wrote:
> >
> >I just found a vendor who has 12SJ7 tubes with pre-amp schematic. He
> >says that 12SJ7 is for military use and has good sound.
> >Should I believe him?
> >What' are the advantage and disadvantage of 12SJ7?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Actually, you've been listening to these tubes for years. They were
used extensively in the electronics of the legendary Ampex 350 tape
machines.

The classic Blue Notes, Orbison, Presley, the vast majority of late 50's
early 60's recordings were made with these tubes as tape head preamps,
not too different than RIAA phono preamps (NAB vs. RIAA curves).

The 12SJ7 with metal housings are reputed to be slightly more prone to
noise than the glass tubes.

You might find 12SJ7's make a really fine preamp.
____________________________________________________________________ MS