From Whirlwind:The only A,B A+B switch with patented noiseless optical switching.Functions as a 2 to 1 or 1 to 2 switch.Operates with 9V battery.The famous Whirlwind Selector is the only A/B A+B box that provides totally noiseless switching between channels. Send one guitar to two amps or use it the other way around to select between two guitars into one amp. Whichever way you use it, the Selector is the best channel-switching device money can buy.The Selector can be powered by either a 9-Volt battery or DC adapter. Older models have a 3.5 TS power jack (tip positive) and use DC adapter T401-ND. To insert a battery, simply remove the 4 screws from the bottom of the unit and clip a 9-volt alkaline type battery to the battery clip. Replace the bottom and screws.On the Selector are three 1/4” jacks, one 2.1mm DC jack (center negative), two LEDs and two footswitches as outlined below.I/O PORTA 1/4” jack that should be used for input from a musical instrument when the unit is being used as a 1-in, 2-out device, or as an output to an amplifier when the unit is being used as a 2-in, 1-out device.A and B1/4” jacks that should be used as outputs to an amplifier when the unit is being used as a 1-in, 2-out device or as inputs from musical instruments when the unit is being used as a 2-in, 1-out device.A/B (Switch)When pressed, toggles the I/O port between “A” and “B”.BOTH (Switch)When pressed, engages the A and B channels simultaneously. When pressed again the selection returns to the channel indicated by the flashing LED. The BOTH feature is not recommended when using 2-in, 1-out connections.LEDsIndicates which jack is selected for output or input. When the BOTH feature is engaged, one LED flashes and one is fully on. Toggling the A/B switch will alternate which LED is flashing to indicate the channel that will be active when the BOTH feature is turned off.
