3 band eq pedal?

[benallison]

I found this schem for a 3 band EQ on the site:

http://www.mitedu.freeserve.co.uk/Circuits/Audio/3band.htm

But apparently it needs a buffer if i want to make a pedal out of it. Could I get away with just dropping in one of these?

http://www.muzique.com/lab/buffers.htm

Maybe the 4th one down?

And, if I'm building this into a pedal, like a DS-1, do I still need a buffer, or do can i just drop it in before the volume knob?

[Mark Hammer]

If built into a pedal (which it often s) the preceding stage should take care of all the buffering needed.  If standalone, then yes a buffer such as the one shown would do the trick.

[aron]

There's also this forum:

http://www.diystompboxes.com/smfforum/index.php?board=21.0

[wampcat1]

I like this one best for an active eq -  http://www.geofex.com/Article_Folders/EQs/greq.gif

bw

[stm]

It has been discussed on several occasions here that the textbook single-opamp three-band Eq is very attractive at first sight, yet in practice has several drawbacks such as: strong band interaction, inability to modify band frequencies without messing with the other bands, and cutoff frequencies inadequate for guitar use--who wants 20 dB of cut or boost at 20Hz and/or 20KHz?  Remember, there's no free lunch!

Guitar amp tonestacks offer another simple alternative which is better suited for guitars, however most of them won't allow mid frequency boost, and there is no simple or definite "flat" control position.

The two circuits linked below are good alternatives, have their frequency response tailored for guitar use, bands behave well with respect to each other, and offer a flat response with all pots centered:

http://www.aronnelson.com/gallery/main.php/v/STMs-Circuit-Ideas/Modified_Sans_Amp_GT_2_equalizer_with_midband.png.html
http://www.aronnelson.com/gallery/main.php/v/STMs-Circuit-Ideas/Three_band_Eq_non_interacting_bands.png.html

Both circuits need an input buffer for standalone use.

[Morocotopo]

I can say that I used the second schem linked by stm and it works perfectly, does just what he says. Try it!

Morocotopo