ok, i played around with it a bit more.
now, the front pot is volume for the front pickup.
the middle pot is volume for the back pickup.
the back pot has no effect whatsoever. pulling the pot gives more midrange.
inside the electronics compartment, there are two pots, that can be turned with a screwdriver.
one is the gain pot of the preamp.
but what the other one does is not clear to me.
it seems to boost the bass, but in all settings. i mean pulling/pushing the pot in the front: it all has the bass boosted then.
can someone please explain all that to me ?
Trim pots & DIP switches: [Invalid or Expired Link Removed]
Control knobs: [Invalid or Expired Link Removed]
Relevant text in the box to the right of the pix:
PCB: TB-05B
Master volume, Pickup balancer
Treble: +18 dB/-6dB at 5.5kHz
Bass: +16dB/-6dB at 90Hz
(TB-05B controls)
3 position gain dip-switches
*When turning #1 to the on position
(in case of turn #2 & #3 off)
Output would be a reduction of 80%,
34mv ~ 38mv
*When turning #2 to the on position
(in case of turn #1 & #3 off)
Output would be a reduction of 40%,
62mv ~ 70mv
*When turning #3 to the on position
(in case of turn #1 & #2 off)
Output would be a reduction of 30%,
78mv ~ 86mv
*When turning #2 & #3 to the on position
(in case of turn #1 off)
Output would be a reduction of 50%,
54mv ~ 62mv
Middle trimmer: +10dB/-6dB at 400Hz