The original Supro 16T circuit design is similar to other single-ended Class A amplifiers from the period, but subtle differences are present. The filter network following the first stage rolls off bass and treble content where the tonestack of a Fender Champ or Princeton normally resides. The Supro's single Tone control is placed after the second pre-amp stage. Thus, more high-end signal is present to drive the second stage. Also, there is no use of negative feedback to reduce distortion. This circuit produces a wide range of sounds that do not sound much like the Fenders, Voxes, and other famous names; it has it's own character and identity.
More information about the circuit can be found on the Runoffgroove website.