[James Romeyn]

In OEM form my 3-ch amp had small 42k pot wired at input (on the rear panel) for channel level trim.

As suggested by the importer I removed the pot from the circuit.  Obviously, removing 42k increased the input impedance significantly above the OEM 24k-Ohm spec.   

I suspected the sound might improve by re-connecting the 42k resistance across the input (no wiper) and I was correct.  The upgrade was quite huge.

Is there any reason to suspect performance might improve replacing the pot resistance with with a fixed resistor of my preferred variety (Dale)?   

[*Scotty*]

I would try a PRP brand resistor,it is just a little bit better than than the Dale. I suspect the pot is a carbon film type and either the Dale or the PRP should have a little lower grain. You could also try a Mills non-inductive resistor as well.
Scotty
 The PRPs are available from Parts Connexion

[James Romeyn]

Thanks, Scotty, especially for the PRP recommendation! 

Have you ever heard a difference between a parallel resistance such as described, pot (no wiper) vs. fixed resistor?
 

[*Scotty*]

I have not run into a situation like you described but when adjusting the offset out of a differential input via a small trimmer pot I have then replaced it with a fixed resistor to good effect.
Scotty

[James Romeyn]

Thank you sir!   

I shall report results to class later!