Update!
I've done some poking around and some barnyard engineering, and I think I would have to concur with what
@bowanderror said earlier in the thread. Short answer is I believe the Bass pot needs to be wired lug 1 to Treble lug 1, and Bass lugs 2+3 to Mid lugs 2+3.
In order to try to figure this thing out, I de-soldered all of the EQ pots and the caps and resistors that make up the tone stack. All parts tested fine out of circuit. I attached some jumper wires at the start and finish of the EQ section of the board, and rebuilt the entire tone stack using alligator clips. I really wish I had a breadboard, that would have made this much easier.
First test I ran was just jumping over the EQ section of the circuit and testing it that way. Tone was pretty much identical to my bypass tone, just much louder due to the Volume control. I then patched in my alligator EQ with the bass pot wired as per the schematic. This produced the same issue I have encountered as well as
@almondcity, bass knob not really doing much until maxed out, which at that point it causes a huge bass cut. I then swapped my clips around to how I stated above and things seemed to work more effectively. Minimum rotation on the pot was still a large bass cut, but you could hear the frequencies coming back as I rolled the control forward, especially early on in the rotation. This was more noticeable when playing bass as opposed to guitar.
So I had made headway on the issue, but I was still curious as to if I was on the right track or not. I decided to hop on to the Duncan Tone Stack Calculator and just look at how the thing was supposed to behave. I plugged in the values from the schematic and here is what I found.
Bass Control
My graph above is showing Mid and Treble controls at 50% rotation, and then the Bass control swept through 0%, 25%, 50%, 75%, and 100% rotation. What is interesting to me is where the control is manipulating the most frequencies at. From 25% rotation through max, things are only really changing below 100hz, but the first 25% of the rotation is flattening out all the way up to 400hz a fair bit. So to me it seems that the Bass control is not actually doing a whole lot on its own past that first 25% of the rotation. This all seems to jive with my findings that the early part of the control was changing the sound more noticeably, as well as it being easier to hear when playing bass.
Mid Control
Again, my graph above is showing Bass and Treble controls at 50% rotation, and then the Mid control swept through 0%, 25%, 50%, 75%, and 100% rotation. The Mid control looks to scoop and flatten fairly consistently and seems similar to the behavior of the control in real life.
Treble Control
Same deal, my graph above is showing Mid and Treble controls at 50% rotation, and then the Treble control swept through 0%, 25%, 50%, 75%, and 100% rotation. The Treble graph and real life control seem to behave in a similar way as well.
"Flat EQ" settings
I was playing with the sliders on the calculator and wanted to see how flat I could set the EQ. You will see here the graph of the EQ with all knobs at 50%, and the other mostly flat line is Bass and Treble at 0% and Mid at 100%. While not a completely flat response, it is pretty close. I hooked up my test circuit again to see if I could replicate this. Sure enough those knob settings provided a significant loss in volume, which was easily brought back to unity with some help from the Volume control, and the tone was practically the same as my bypass tone.
All in all between my real life tests and the EQ graphs, I think I have convinced myself that swapping the Bass pot wiring is going to remedy my issues and the circuit will be functioning as intended. I am thinking that maybe with the pot being audio taper and the wiring being backwards was sweeping through the most responsive resistances of the control too quickly, so the control seemed to not be doing much of anything to the ear. I just need to order a new pot since I cleaned the old one with some Deoxit and it now spins way too freely for my liking. Oh well, might as well get some parts for another build while I'm at it!!!
