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.