[Hammarlund] HQ-129-X Mixer Noise

[Frank Barnes]

I'm new to the group and have an old subject which I'm sure has been
discussed multiple times.   I've restored an HQ-129-X and I really like
it.   It was a lot of work to bring it back!
I really like the quality and love the 3-IF system.  I'll use it mostly on
40M CW and for some general SW listening.
However it seems to have a lot of "noise" - sort of a background hash.
 More than some other receivers I've used, including my Halli S-40B.
Disconnecting the antenna eliminates the noise so I think that means I'm
hearing noise radiated from power lines, appliances, etc.

Am I hearing mixer noise?  I've read about replacing the 6K8 mixer with a
very expensive 6SB7Y (requires some rewiring).

Does anyone have advice regarding quieting the mixer noise, other than tube
replacement?

I'm also interested in replacing the RF tube with a better one - 717A?
6AC7? 6BZ6 mini?  Any advice/experience?

-- 
Frank Barnes
W4NPN
Chapel Hill, NC
Grid Square FM05
Cell 919.260.7955