I'm using the standard DC power jack, the one that measures 2.1mm. I had also built a tonepad version with the DC power jack. It is a design that people seem to question because it's a PNP transistor with a negative ground. It's VERY noisy, but the tone is phenomenal. Do you think the power source is the problem? I've heart the Rangemaster is really noisy anyway; the presence of a band could probably mask the noise...the TV at moderate volume does!