Semi parametric EQ for Dr Boogie : looking for suggestions and comments

[ricothetroll]

Hi,
I built a Dr Boogie for my guitar player a few months ago. I recently borrowed it to him and it appeared obvious to me that, as a lot of people here, the tonestack is pretty non effective. As I already had hole for those 6 pots fitted in enclusure, I decided that I could use this room to implement a parametric EQ, kinda like in the Boss MT2 (maybe that's the only thing I like about that pedal).
While simulating the MT2 tonecontrol, I didn't find it very satisfying because it has a lot more ability to boost than to cut bass and trebles. I then decided to add a classic, studio-like, parametric EQ. For Low and Trebles, I modified the active Baxandall found here :
http://sound.westhost.com/dwopa2.htm#baxandall
For the parametric Mid control, the low-mid stage of the Calrec PQ1549 EQ from Gyraf :
http://www.gyraf.dk/gy_pd/calreq/calr_eq.gif
It's based on an active state variable filter, as described in "The Art Of Electronics" from Horowitz-Hill, page 276.
The resulting schematic is here :
http://www.wuala.com/ricothetroll/public/DrBoogieEQ_schematic.pdf/ (click on "Télécharger 'DrBoogieEQ_schematic.pdf' sur votre ordinateur", or maybe something like  "Download... on your computer")
And here are the results for the simulations :
http://www.wuala.com/ricothetroll/public/DrBoogieEQ_Low_Shelf.pdf/
http://www.wuala.com/ricothetroll/public/DrBoogieEQ_Hi_Shelf.pdf/
http://www.wuala.com/ricothetroll/public/DrBoogieEQ_Mid_fixed.pdf/
http://www.wuala.com/ricothetroll/public/DrBoogieEQ_Mid_variable.pdf/
Before building it, I'm looking for your opinions and suggestions for eventual further mods. If the project looks viable, I'll do a PCB, keeping Gaussmarkov's layout for the "preamp" part (Eagle files are available on his website) as people seem to be happy with it, and adding the EQ part near it. I'll post the whole project files here then of course.
Best regards.
Eric

[WGTP]

The tone section of the Boss Rod10 might work, if not similar. 

http://www.aronnelson.com/gallery/main.php/v/KHE/Boss_ROD10_Schematic.jpg.html

[ricothetroll]

Hi !
Yes that should also work ! Though the topology isn't exactly the same : the Bass/Treble is a modified James stack and the mid section is the same as in the Metal Zone (simple RC bandpass instead of state variable filter). If mine doesn't sound well I'll try that one (I'm not very fond of Boss pedals  )