I built this for those of you who have guitars with single coil pickups or indeed anything that picks up mains interference up (that annoying set of speakers in my bed room for example) anyway this little device reduces the mains hum by several orders of magnitude
it is adjustable between 45Hz and 90Hz so just put it before your amp or whatever and adjust the trim pot till the hum goes away.
it uses the same Texas Instruments TLC071 OP-AMP as I used in the last project for pretty much the same reason
