[sdiy] the dreaded SH-101 hum

[media at mail1.nai.net]

>I have three power supplies of varying quality (one is
>very good) but they all put out the AC hum (and did so
>before the MIDIJack installation).

Have you considered a nice linear power supply instead of a wallwart??  I'm
thinking a three-legged regulator would be an improvement, but you can buy
a 723-based supply, such as a Power One, for about $35.