67 Vibrolux Reverb noise issue

[Pater Familias]

I just received shipment of a 1967 Fender Vibrolux Reverb in mostly all original condition with only a cord change and a few caps and such.

Sounds glorious but does have a white noise issue that sounds like static on an old radio. In fact, it almost sounds like a radio does when the signal is static'y but waxing and waning in and out.

I think it's something in the Normal channel, because if I turn the Normal Vol to 0 the sound stops. I hear it whether I'm plugged in to either channel or not plugged in at all.

I live in an old house and no doubt have dirty power, but since the Vibrato Channel's nice and almost dead quiet I figure it's in the amp.

Bad preamp tube? Bad Volume Pot? What do you guys think?

Thanks for any help.

[martin manning]

The usual suspects are preamp tubes, especially the first one (try known good, quiet ones, or swap V1 and V2), poor contact at the pins (try retensioning the socket contacts and use contact cleaner such as Deoxit on the pins and insert and remove a few times), and noisy carbon comp plate load resistors. There are other possibilities but that's a start.