[bakon_boy]

Wondering how you can add voltage control to a toroidal PSU like a KL-6020? I know you can remove coils but I am hoping to basically add a dial to reduce the voltage by up to 20V.

I am wondering if you can add one of these on the AC side to in turn control the voltage on the DC side. Or maybe theres a better way.

I have a basic understanding of electronics but this stuff goes way over my head. So any insight would be welcome.

[doorknob]

I doubt that the control to which you linked would be satisfactory.

Rather, a Variac or similar autotransformer would do the job. Something like this:

TDGC ? 3KM Variable Output AC Convertor (Metered Variac) | Automation Technology Inc

(I'm only guessing that the link that I gave is for an autotransformer, but looking at it more closely, I can't be certain that inside the housing it is actually a Variac clone, instead it could be a switching unit which might be less satisfactory than a true Variac.)