how would I get power to a rack tuner? Im thinking of getting a korg one. Does it plug into and outlet then go in the rack, or do you loop it through the effects or other jacks on the actual amp head? Plus, to tune, do you need to unplug your cables from your head then put them in to the tuner? Alot of shows I see, the bassist has the white face Korg tuner that has a red block that goes back and forth while playing, in a rainbow shape. thats what im looking for.