New amp problem: treble pot not doing anything

[art_lessing]

Well I went and bought a 1982 Fender Concert II Head for $647.00. I am really happy with the sound of it. Although the treble pot on the clean channel doesn't seem to do much. Is this normal for this V-T-Bass tone stack for this amp? Everything else works great...and the tone of the clean channel sounds pretty damn good. I just am concerned about this treble issue. I can't seem to really roll much if any off.

DQ

[Jazz P Bass]

Looking at the schematic, the tone stack appears pretty straight forward.
It uses a 250pf capacitor.

Does the 'Bright' switch do anything as far as increasing the Treble?

concert_ii_83.pdf

[art_lessing]

The bright switch makes bright. The presence knob makes it present. the bass knob closes/opens path for the bass signal, the treble knob just doesn't seem to close off the treble signal in any position (0-10). So am I correct in assuming that the treble knob should make it go from muffled @ 0 to crystal clear @ 10? or is the stack more subtle than that? this is all in channel one by the way. Channel two works perfectly awesome.


DQ

[52 Bill]

So am I correct in assuming that the treble knob should make it go from muffled @ 0 to crystal clear @ 10? or is the stack more subtle than that?

There isn't much difference in nearly any Fender tone stack, so the treble control should work in a similar fashion to the one in the other channel.

The pot may be broken or it may have a cold /broken solder joint, etc.

[Mick Bailey]

The TB control is similar to the other channel, but with a fixed 6.8K mid resistor instead of a 10K pot, so should behave roughly the same as having the mid control on the 2nd channel set to 6.8/10.

If the treble pot does very little, but there's a good level of bass and mids, you may have the treble-side pot lug disconnected (the fully CW end looking from the front), an open 250pf treble cap, or bad joint on that side.

You should be able to meter out the circuit to check.