The buffer is powered by a +9 -+24 adapter and has an TRS (1/4 inch Jack) input and output sockets and a power connection. Other instruments can also benefit from the use of this device. It has a lot of overload protection headroom, which depends on the power supply: +9V for a guitar, +12 – +15V for the keyboards, and +24 – +27V for a high gain line level source. Why is it called a guitar buffer then? A guitar is a complex and demanding instrument and the buffer effect is very obvious when used on a guitar.