Assertion: amplifier's circuit | /r/CapableOf | introduce tone controls
Facets:
value: for treble
type: PURPOSE
value: for bass
type: PURPOSE
Source sentences:
text: About this time, the "Top Boost" (or "Brilliance") feature became available as Vox's optional addition of a rear panel-mounted circuit that introduced an extra gain stage and tone controls for bass and treble (as opposed to the single "tone" control of earlier AC30s).