EQ + Distortion Pedal

[PoopLoops]

Hi all, this is my first (2nd actually) post here.  My Roland Microcube doesn't have any EQ settings and my current distortion pedal (Line6 Ubermetal) still has a lot of gain even when distortion is set to the minimum (It has EQ on it when activated).  So I thought I could do a better job than some 2-bit well-educated electronics experts. 

I found an EQ schematic some time ago (credit goes here



So the problem I have with this one is that it only has on/off switches for setting EQ. I'm not 100% on what is going on here, but I assume that replacing the switch + 1Mohm resistor on the LO and HIGH parts of the circuit with a pot will let me control the boost.  But, if I were to replace the switch in the MID section with a pot that connects both parts to ground, I could control the boost and cut.  So if I were clever I could just use that same setup for the LO and HIGH sections for more control.  Is any of that correct?

Also, I have no idea how to change the peak frequency.  I know it's down to the RC of it, but I'm not sure how this stuff works.  I'm not 100% with op amps.  Is it basically cutting off all other frequencies and then boosting the whole thing?  So for the LO booster, it's a low pass filter, so it cuts off higher frequencies, but then does the op-amp boost everything back up, in essence amplifying the lows and restoring the other frequencies back to their previous (input) values, and continued with the MID and HI boosters?  Sorry if I'm not making any sense, it's getting kind of late.

On this page is an alternate schematic for a parametric EQ circuit (3rd and 4th pics down) that works with LC circuits as opposed to just RC ones.  It seems a bit "cleaner" in that the parts are almost like modules instead of one steady flow of circuits.  Also, I can figure out what is going on a lot easier in this one.  L and C create a band pass filter and the Pot between them determines how much of a boost or cut you get to that specific range.  The 10k pots right before the op amp control volume.  I'd rather go with that one, but I have no idea what op amps to use in this case.  We pretty much just used 741's for everything in class. :p  I know those aren't exactly good for anything fancy, so I have no idea what else to use.



Lastly, I'd also like to add a distortion circuit to this thing if I could.  I could either go all out and have 9 knobs for the parametric EQ or keep the resonant frequencies static with static bandwidths and have 1 knob each for lows, low mids, high mids, and highs (volume only) or 4 knobs that are lows, mids, highs, and bandwidth.

Gah, anyway, I don't now what kind of distortion circuit to use.  There are so many to choose from and I'm not 100% sure on what a lot of their specifics are (Fuzz Box isn't very descriptive besides implying fuzz).  Just basically looking for something that will let me play some blues all the way to metal, but not to the point where it is *real* noizy like fuzz is.  Is that something I would just get to set, or does it really depend on the circuit?

Thanks a lot to anyone who managed to survive this post.  Sorry for making it so long.