Simple pre-set eq!

[Bill Mountain]

Here is an easy pre-set eq curve to play with.  I took this from an old Sunn Coliseum 300 head.  I really liked the "Contour" switch and I searched out the schematic to see what it actually was.  I've used this to sweeten the sound of a few pedal projects but I never found a permanent place for it.

It was described as a 6 dB boost at 50Hz and 4kHz and a 3dB cut at 600Hz.  That's not necessarily what the frequency graph shows but its close enough.  This is probably best suited to bass but I'm sure the values could be tweaked for guitar.  

If you turn the 10k resistor into a 10k pot you'll have a bass control and if the change the 6.8k into a 10k pot you'll have a treble control.  This circuit single handedly sparked my interest in active filters.

You can eliminate the buffer and put this circuit in the feedback path of a non-inverting stage (with necessary modifications) but you won't be able to go below unity in the midrange which is part of this circuit's charm.

Have fun!

[WGTP]

Cool.

[wavley]

Neat!

[Bill Mountain]

I had thought about making an EQ pedal that was just this guy with a bass control.  It sounded great on the breadboard but other projects came along that demanded my attention.

[Bill Mountain]

I wanted to bump this because it got kind of buried and I really like this circuit and want to make sure some more people see it.  I may try to fit it into a CMOS design I'm working on.

[pinkjimiphoton]

thanks bill!!

"ethel was a tree growing outta his shoulder"....


classic.