I would imagine that that you install the volume and tone before the psycho knob, the diagramme is from the CB Gitty website
I would wire it in between the vol/tone pots and jack.
I'm assuming that the psycho knob circuit is input sensitive, meaning it will perform differently at different input levels. If that's the case my thought is it would be better to run the pickup output straight to the psycho knob and wire the tone and volume pot after it. That way the psycho knob circuit is always getting the full direct pickup output and theoretically should have the same sound at any volume setting. I'm certainly no electronic genius and may very well be completely wrong.
It's basically a effect circuit. And most guitar with onboard effects are wired after the pickup vol/tone controls like the way pedal effects come after the pickup controls(if any).
I'm starting to think that wiring the effect before the vol/tone controls would change the level/intensity of the effect more than the pickup, which isn't a bad thing. I see on the schematic that Pickedmoor Jon posted, that there's a area at the bottom labeled: Level. That would be an ideal place to add a Level/Intensity pot to control the strength of the effect in the circuit. That way you could adjust the pickup with your original controls and possibly adjust the effect.
I'd love to see a detailed pic of one of these.
I would disconnect the wires at the jack on your guitar, solder/attach them to the effect and then wire from the effect's output to the jack. Then if you could add a pot for the level, that would be awesome.
If you were good at hacking and soldering without destroying a board, you could remove that block and wire in a pot for extra adjustment benefit.
On the back of the board, there's 3 points to solder the block in. You could remove the block and solder wires there for a pot. Find the ground first and run that to the back of the pot and the 3rd lug. Then just wire up the other 2 to the 1st and 2nd lugs. If it doesn't work well, reverse the 1st and 2nd lug wires and it should work fine. You would probably need a B2k to B10k pot.
I'm an electrician but not great with electronics yet. I'm also from the UK so we call things by different names, let me see if I get what you are saying. Remove the 10 Kilo ohm variable resistor from the QDD2 board, solder wires from those connections to a new pot of the same value. This will adjust the distortion intensity rather than having a fixed intensity on the overdrive setting of the psycho knob (QDD2), have I got that right?
On a basic electronics question (as I said I'm a newbie to electronics). A VR or pot has 3 legs, the Input, the fixed Output and the Wiper (variable value resistance) What would the Ground be connected to? I can see that you want an adjustable voltage/amperage so that takes care of the input and wiper but what is the third leg for? Is the ground just for attaching to the chassis of the pot to the QDD2 ground or Guitar?
Thanks in advance to any and all who can help.
Your simply replacing a fixed resistor with the variable type.
The ground goes to lug #3(looking at the bottom of pot-lug will be the one on the far left) which also usually gets grounded to the back or side of the pot and added to the guitars ground circuit.. The far right lug is #1 is signal in. The middle lug #2 is the wiper.
BTW: if your a lefty - change out lugs #3 and #1 for ccw rotation.
Hope that helps. The fixed position might be best, try it first. Then If you would rather be able to adjust for certain use, you know how to do it. Cheers
I've done a bit of looking around and found these drawings, it gets us a bit closer.