[Boatanchors] Question About Receiver Design - Crystal Controlled Converters

[whitebear1122 at comcast.net]

I'm looking at Byron Goodman's HB67 receiver in the ARRL Handbook 1965.  His
design uses crystal controlled converters for 40-10 ahead of an 80 meter
receiver.  I see this is single conversion on 80 meters as it bypasses the
converters, then double conversion on 40-10.

 

What are the advantages and disadvantages of this configuration over the
other receiver designs where the local oscillator is changed to mix 80-10?  

 

Thanks. 73 Scott WA9WFA