The de Lisle Amp-Speaker Selector (Version 1) was designed as a studio tool to conveniently route the output from any of the connected amplifiers to an isolation cabinet. Alternatively, a single amplifier can be paired with one of up to three individual cabinets. Signal and ground connections from the amps are isolated, and as a precaution, the unused amps see a load. Similarly, when used as a cabinet selector, jacks with no cable inserted will be switched to an internal load. So, one can use a single cabinet or two cabinets without worrying about switching to an open cabinet jack.