6 points to tonestack calculation
1. identify low and high pass filters
2. identify series and parallel filters
3. identify the Volume Attenuation
4. identify basic pathway the signal in to the signal out
5. Understand phase shift and amplitude
6. Understand the math for series and parallel filters
The following diagram shows the classic Marshall / Fender tone control circuit.
In a Marshall or
Fender amplifier, this is usually installed between the 2nd and 3rd 12AX7
amplification stage. You might choose to place this somewhere in the
"multi-variant" pre-volume arrangement, or just before the phase
splitter stage. Experiment! Probably the only completely inappropriate place to
install this circuit is just after the input jack, because the gain there is so
high that you'd never be able to wire it in a way that wouldn't pick up a lot
of noise. Note that the Bass control is wired counter-clockwise from the
schematic.
Fender Marshall
R1 = 250K R1 = 250K
R2 = 250K R2 = 1M, log
R3 = 10K
R3 = 25K
R4 = 100K
R4 = 56K
C1 = 250 pf C1 = 250 Pf
C2 = 0.1 uf C2 = 0.022 uf
C3 = 0.047 uf C3 = 0.022 uf
