Quote Originally Posted by mister_e View Post
Unfortunately i don't have anything like that here to test, but Maybe the PWM have to be smooth first...

what happen if you place a big capacitor (470 & up) in parallel with the motors?
Tried both high (1000uf) and low (100uf) - the loco won't move

Quote Originally Posted by mister_e View Post
What happen if you place a capacitor (few uF) on the mosfet gate pin? (transistor base)
Tried, 1uf to 10uf. with a 1uf the growling was less noticable, but the slow speed control became less. Increasing this to 10uf and the loco had almost no ability to crawl.

Quote Originally Posted by mister_e View Post
What happen if you use a variable voltage regulator (or PSU)? instead of PWM?
Don't know as I don't have a varible regulator to hand.. what would be the advantage of using one over using a pot accross the supply with the wiper connected to the base of the NPN tranny ?