Hi Beros,
As I am reworking some wah projects, here is a good occasion for me to ask you some informations about what you've done here - if these infos are available, indeed :
1 - the Q's seems to like BC107/8/9 - exact type ? Have you measured the Hfe of Q1 and Q2 ?
2 - the inductor looks like a Fasel (or may be a copy ? You find a similar one in look in the today's standard GCB-95), have you measured the self-inductance (mH) and DC resistance (Ohms) ?
3 - have you added a serial and/or a parallel R to modify its Q factor ?
4 - is it a wide-band wah (suitable for... everything) or a narrow one (talking wah) ?
5 - is it a sharp one ? - I mean the treble kills ans the bass is moderate (acceptable in lead), or is it a smooth one, with nice bass, smooth high and smooth transistion (acceptable in rhythm and... everywhere if you want to save your ears)
For example, it is clear that the today's GCB-95 is a great seller, but I personnally feel that it gives a too much agressive, piercing tone. Moreover, there's nothing very different with the 1996 or 97 version I have. I had also a JH-1, but it was a too narrow band wah to be OK in rhythm wah sounds. In comparison, my 70's Colorsound Wah Wah is neatly more multi-purpose, so is my 70's Shaftesbury HA-9P.
Here's a pic showing the inductor of a 2010 GCB-95 :

And for the fun, my Colorsound Swell Pedal DIYed in wah pedal - works nicely to my taste, but the coil is too much vibration sensitive-noisy that I will have to do something on it or sadly replace it. Its brand is "Adjustoroďd Barnell & Co", and it is a 600mH / 70 Ohms inductor :


Thanks in advance for your technical help, Beros
A+!
I am searching - so that's the reason of my precise questions !
A+!