Carnage
Mar 11 2004, 14:05
Excuse my ignorance, but when designing a baxendall bass tone control to add in an audio power amp (with a 741 pre-amp feeding a 384), how do the values of the 2 resistors, 2 capacitors, and potentiometer define the bandwidth and centre frequency?
Thnaks
Rigapada
Mar 13 2004, 23:53
The formulae required for calculating the gains and points of inflection are given in the Linear Data Book of National Semiconductors:
Let R1 be the two resistors on either side of the pot, and C1 be caps connecting the tap to the end points of the pot, which is R2
Max bass gain~(R1+R2)/R1.
Point of Bass inflection ie point of rise of gain from 0db is 1/2piR1C1
Point of max gain reached at is 1/2piR2C1
for typical values of R1=11k, R2(pot)=100k, C1=47n,
Max Gain=20db @32 hz, inflection starting from 320 hz.
Rigapada