In an amplifier, does the gain knob boost or attenuate the input signal?
It could be either when determined by marketing. Two common configurations are shown below.



simulate this circuit &ndash; Schematic created using CircuitLab
Figure 1a: Fixed gain pre-amp with preceding attenuator. 1b: Variable gain pre-amp.

1a is simple but has the disadvantage that the noise from OA1 is constant even with the input turned to zero.
1b has the advantage that as the gain is reduced so is the noise.

(Gain in the example circuits is -R2/R1 or -R5/R4.)