G&L PBT wiring

[xaxxat]

Anyone have any drawings/pics of G&L's Passive Bass Treble circuit?

[line6man]

If you're talking about the passive bass and treble controls common to G&L basses, that's nothing more than a standard tone control, plus a capacitor in series with the signal path, with a 1M pot parallel to the capacitor.

There is a schematic of it somewhere. I'm on my phone, so I'll have to search for it later.

[Stealth]

Here you go.

[xaxxat]

I ran across this pic. Is it not a L-1000? It looks quite different from that schematic.

[xaxxat]

This one is different too.

[Stealth]

Both schematics are, from C3 to the output, functionally the same. To change how the bass sounds when the treble control is fully open, use a 250K VR3 for a vintage one with less treble, and a 500K VR3 if you want a modern tone with more zing.

C3 is probably there to give a bit more growl to the tone (a lower resonant frequency) even with VR3 fully open, and R1 gives it a generally brighter tone with more resonance (a higher peak). As for the SW1/C2 combination, that gives the series mode slightly less muddiness.