No, just turning the switch on the sub off might do what you suspected, i.e. lose the bass. You still haven't identified your receiver, but you have to set it so that there's either no sub or a "pure" etc. mode which sends nothing to the sub. If the receiver is sending bass out to sub, but the switch on the sub itself is turned off, there's nowhere for the bass to go.

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Enjoy the music, not the equipment.