There are lots of circuits on the net for 3 band EQs but I wanted something a bit more powerful than the usual 20+dB/20-dB things on offer so I went on eBay and bought some grey market MC3340P attenuators from china and made this thing.
I made mine for a send/return loop in a very simple valve amp I have but it's perfectly capable for hi fi audio.
it's worth noting that this works very well if you turn the knobs slowly because they aren't actually in the audio chain - they are part of the voltage control architecture of the chip
It's also worth noting that it will work on 9 volts if you want to make it into a guitar pedal.
