wrote in message
...
I have a Fender reissue model guitar amp in for service. It has 2
Fender 12AX7's that are microphonic. These are Chinese manufacture. I
have replaced them with 5814's which is some sort of 12AU7 type just
to get the amp working. There is no more microphonic problem, however
the amplifier sensitivity is now somewhat lower so perhaps that may
have a bearing on this. I realise that I have no 12AX7's in the shop
at all and would like to buy several, two for this amplifier and two
or three for stock. I was looking at NOS and JAN types online and
would like to go with either but I suffered real sticker shock when I
noticed the prices. I don't have much faith in the Russian or Chinese
tubes so I was hoping that someone could offer some advice as to a
source for good preamp tubes either new or tested used, and ones that
I don't have to worry about microphonics. Thanks, Lenny.
I've had some complete junk Chinese tubes, e.g. power output pentodes that
burned the cathode resistors on the first use due to internal shorts. I've
had good luck with Russian tubes however, the Svetlana ones seem to be very
good but you must make sure they're the St.Petersburg manufactured ones and
not the Sovtek ones; see the bottom of this page for more information:
http://www.amp-fix.com/biasing%5B1%5D.htm
Martin
--
martindot herewhybrowat herentlworlddot herecom