This is a rare Martin-branded version of the DeArmond R15 amp, dressed in its own distinct styling to set it apart. With two volumes and a single tone control, one might expect something along the lines of a Tweed Deluxe, but this amp truly has its own unique personality. The interaction between the two volume controls is especially distinctive, opening the door to some great and interesting tones as you experiment with the levels.
Internally, it has had the power cord and electrolytic caps replaced, along with a handful of resistors/caps swapped for modern equivalents. A plate-to-plate snubber cap has also been added, helping tame oscillation and smoothing out some of the unwanted upper top end. See the circuit photos for more details. The speaker is a period-appropriate Jensen P12Q from 1962. Overall, this is a fantastic vintage piece that really needs to be played to be fully appreciated.