PRS Guitars and John Mayer have teamed to develop the J-Mod 100, a single-channel guitar amp with switchable gain stage and effects loop. It uses four 6L6 power tubes, four 12AX7/ECC83S preamp tubes, and employs separate/dedicated circuit boards for the preamp section, power section, front-panel controls, bias jacks, and effects loop. Other features include controls for Volume, Tone, Treble, Mid, Bass, a Bright switch, and a Presence control that boosts the high-end in the power amp. The effects loop and gain stage can be controlled by the footswitch. Read more at prsguitars.com.