[Collins] 51J4 audio improvements??

[Paul]

Hi Group,

I am the proud new owner of a very nice 51J4 with 1.4, 3 and 6KC filters
installed. The rig is all original and in very good shape (for it's age). I
went through it last night and cleaned all switches and contacts and it is
now working much better.

I am comparing this radio's audio to my Racal 6790 and yes, it is 40 years
older than the Racal, but I was expecting a little nicer audio from it. It
may just be the nature of the 6KC filter as well. I am going to do an
alignment on it over the holidays but I have a few questions.

How good can the audio from this radio be? I have use GPR-90 and R-390 and
find they were much more musical. This one may just need a good alignment
too. Can I pull out a mechanical filter and just feed in to out with a .01uF
cap? The xstal filter may be enough for hi fi listening.

Any other improvements I could make to the audio quality? BTW, I will be
trying to take the audio from the diode load to bypass the final audio
stages as well.

Look forward to your replies.

Merry Christmas!

Paul