Simple eq circuit

[nee]

Greetings!

I want to build a pre-amp for my acoustic guitar, firstly to bump up the gain a little, but also I'd like to add a simple mid cut control. I've found the pick up usually requires a few dB of cut in the 600Hz - 800Hz region. The design of the preamp itself is no problem for me, but I wonder if someone can point me in the right direction for incorporating the eq? Ideally both the eq band and amount of cut would be adjustable.

Thanks!

[zyxwyvu]

This should get you started:

http://www.geofex.com/Article_Folders/EQs/paramet.htm

[nee]

Thanks for that link. So, reading that, putting a simple twin-T mid-cut circuit in a preamp would most likely have too broad a bandwidth to be useful?

[zyxwyvu]

Thanks for that link. So, reading that, putting a simple twin-T mid-cut circuit in a preamp would most likely have too broad a bandwidth to be useful?

It depends on what you want it to sound like. You can try the bootstrapped twin-t (second to last image), and tune the Q to get the sound you want. If that doesn't do it, you can go for either a graphic eq (complicated to diy), or a parametric eq, which is mentioned in the same link. You would only need one frequency, so you can get rid of some of the circuit that is in the pictures.

[dschwartz]

you could try this..
http://www.diystompboxes.com/smfforum/index.php?topic=71716.0
replace the mid pot for a 250KB pot and the mid scoop is more pronounced