Tweaks for B&K?

These people modify amps.
http://www.musicalconcepts.com/mus_con.htm

I haven't tried them but they have an excellent reputation.

Mods to my ST-202

The Main thing was it was forward Bias'd to run more in Class A(Change the output resistor values) which takes away any veiling associated with the amps signature.The Transformer was changed to a better one.The CAps and Resistors were chnanged also.Star Grounding was used along with all the wiring changed.Better Binding posts were put in.I also changed the AC cable.

Something I was told which would also help is Bypassing the protective fuses.