No heater hum here...

Here is a pic of the guts of my 18-Watt Lite IIb build. Note that I did NOT twist the heater wires and they are NOT tucked neatly into the corner of the chassis. All I did was make sure they are as parallel as possible around other signal wires and most importantly all other wires cross them at 90-degree angles and don't touch them.

This amp has ZERO heater hum...

Google pictures of Soldano amps. They take it to the extreme... the wires are run parallel but they are also about 1" apart.

Discuss if you like below....