Gain Trim Resistors; Figure 7-Tone Control Switch Installed And Wired To Bass Control, Treble Control And Pcb's (Green Wires Called Out In The Assembly Directions Are Blue In The Pictures Above) - DYNACO PAT-4 Assembly Manual

Gain Trim Resistors

A gain trim resistor is a bit of a two-edged sword. The 1210 Ohm value is about the
lowest value that should be used. It reduces the gain, but it also increases the loading on
the output stage. The net effect is positive...if indeed you needed less gain, then the 1210
resistor drops the gain, increasing the SNR for the high level stage.
Here is a table of other values for the gain trim resistors, and their effect on the flat gain
of the high level stage.
Gain Trim Resistor Value
Open circuit
22K
10K
6800
3300
2200
1210 or 1200 Ohms
The unmodified high level stage has about 21 dB of gain when driving a high impedance
load and the volume control is turned fully clockwise.
Figure 7-Tone control switch installed and wired to bass control, treble control and PCB's (green
wires called out in the assembly directions are blue in the pictures above).
Gain Reduction
0 dB (e.g. no effect)
1.53 dB
3.02 dB
4.08 dB
6.7 dB
8.46 dB
11.23 dB
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