Art Harris wrote:
"Tom Holden" wrote in
message
[snip]
Why would the designers add the buffer? What performance
comparison should I make between the A and the B model
to assess whether it would be worthwhile to retrofit a
similar buffer to the A model? I can say that I have not
noticed any dramatic difference with my usual listening
habits.

They obviously wanted to provide some isolation and/or
impedance
matching between the oscillator and the mixer. It's a
good engineering
practice, but may not have much practical effect. If you
don't notice
a difference, then don't bother retrofitting.

The oscillator is an emitter follower, too, so I doubt that impedance
matching is the objective. What would the increased isolation achieve? Would
it preclude mixing of 1st IF energy in the oscillator? Should this be of
some benefit for intermodulation products?

Tom