Audio Engineering

784 Chapter 27





In

C 5

R 1 R 2

C 1

22 n

C 7

10 u

C 8

10 u

C 3 C 4

C 6

C 9

R 6

R 4 R 5

R 3

47 K

C 2

22 n

2.2u

22 K 22 K

220 p

220 K

U1A

Boost

Boost

Bass Cut

Cut

VR2

100 K

VR1

100 K

Treble

10 K 820 p 820 p 10 K

1u

V

V

V

V

4

(^231)
8
TL072 Out
Figure 27.17 : A simple tone control circuit.
Mic/line Full EQ Main mixbuses
input
Insert
point
Main fader
Figure 27.16 : Insert points.
27.6.2 Insert Points
After the channel input amplifi er, insert points are usually included. These allow external
(outboard) equipment to be patched into the signal path. Note that this provision is usually
via jack connectors, which are normalized when no plug is inserted ( Figure 27.16 ).
27.6.3 Equalizers and Tone Controls
At the very least, a modern recording console provides a basic tone-control function
on each channel input, like that shown in Figure 27.17. This circuit is a version of the
classic circuit due to Baxandall. However, this type of circuit only provides a fairly crude