After the frantic soldering fest that was The Pagey Project, I figured it might be time for a nice, simple DIY wiring project. At the suggestion of tonefiend reader JH, I played with variations on the 2-band tone control that appeared in some G&L guitars. And I am over the moon with the results!
This circuit, sometimes called “PTB” (for “passive treble and bass”) combines a standard treble-bleed tone knob with a bass-cut control. The latter has a huge effect on the way distortion pedals and amps respond to the pickups, especially with humbuckers. Cutting some bass makes the pickups sound cleaner, airier, and more dynamic (i.e., less compressed). To my ear, the bass pot is not so much a tone control as a clarity knob.
Check out this brief demo video:
Savvy stompboox builders emphasize the importance of filtering the guitar signal as it enters the effect. And if you’ve built or modded your own fuzz/overdrive effects, you’ve probably discovered how the importance of the input cap’s value. This cap filters out lows. Too large a value, and the tone gets flabby/sloppy. Too small, and it gets thin/shrill.
This tone circuit lets you make similar adjustments from the guitar. And as you can hear in the demo, there’s more to it than just nixing lows. With fewer lows bombarding downstream amps and effects, the signal becomes brighter, cleaner, and livelier. At times you’d swear you were adding highs rather than just removing lows.
This arrangement works great it three-knob guitars, provided you can live with global volume and tone controls for both pickups. Alternately, you could modify it for a four-knob Les Paul so that there are two volume pots and global bass and treble controls.
Here’s the original schematic provided by JH:
I actually prefer how it sounds with three 500K pots — the pots you probably already have in your humbucker guitar. In other words, you can probably mod this circuit without buying anything extra, except maybe some wire and solder.
Here’s a (literally) sketchy wiring diagram I drew up:
Please do like i didn’t the first time I tried this, and note that the bass control capacitor is a .0022uF, not a .022uF like the treble cap. If you’d like a little more treble cut in the fully counterclockwise tone-knob position, try substituting a .033uF or a .047uF for the .022uF.
This circuit also works great paired with single-coil pickups, the way Leo intended. But it seems even more relevant for humbuckers, since low-frequency control is so much more an issue than with brighter single-coils, like classic Fenders or G&L’s signature MFD ceramic-magnet pickups.
This one stays in the guitar! 
Leave a Reply