Assertion: amplifier's control | /r/HasProperty | reverb tone and level controls
Facets:
value: to add further control
type: PURPOSE
Source sentences:
text: Controls include a Normal volume, Top Boost Volume, Treble and Bass controls, Reverb Tone and Level controls, Tremolo Speed and Depth controls, a Tone Cut control (to add further control over the higher-frequencies), a Master Volume, and a Standby and Power Switch.