When I connect the inputs of my two amplifiers, a strong hum occurs. This is a common inquiry in the technical sections of relevant specialist magazines. The solution to this problem is provided by the Palmer Y-Box. A FET input circuit converts the high-impedance guitar signal while simultaneously forming the driver circuit for a transformer that transmits the signal to the output without ground reference, thus eliminating a ground loop. Operation with a 9V battery is recommended.

The PGA03 Y-Box can also be used as a cable driver for long cable lengths. Additionally, the signal from output AMP2 can be switched with a phase inversion, which is often necessary when paralleling two out-of-phase preamps or power amplifiers.