The Imperial Accordion Company of Chicago was one of Estey's biggest distributors of Magnatone and their own rebranded accordion amplifier, the Tonemaster. Imperial was given special input into some of the amplifiers designs that Estey built for Gasparetti (president, Imperial).
Among the founding organizers of Imperial were Carlo Gasparetti, Merico P. Malatesta, Italo Sorbellini, and Felix Vitello. Gasparetti remained a key figure in the distributorship and for the Tonemaster amplifiers. In the mid-sixties, Imperial was the distributor for Illinois (north of East St.Louis) and Wisconsin. Other amplifier builders, like Lo Duca in Wisconsin and Noble in Chicago, might have worked order through Imperial in those days.
There were several Tonemaster models built by Estey, including models based on the 213 as well as the big 260. Gasparetti even sent a small Estey built amp to Italy where one of his Italian manufacturers used it as a basis for an Italian Tonemaster amp (these are easy to spot as the transformers are not Woodward-Schumacher units).
Estey built Tonemasters were mostly identical to their Magnatone counterparts between 1959 and 1962. In 1963, Estey started to incorporate some design changes that made them somewhat distinct
The 214 might have first appeared as early as 1959 as a 213 without any real circuit changes from the Magnatone 213. When Estey replaced the Magnatone 213 with the 413 in 1961, the 214 became a 413 circuit. The 413 circuit added a mellow/normal/bright switch to the pre-amp and replaced the 12AX7 oscillator, which paralleled both triodes with a single 7 pin 6AV6 triode oscillator.
The 214 got a solid state rectifier at some point, probably in 1963 when Estey engineers eliminated the tube rectifier from all Magnatone branded amps. This 214 was a 413 circuit with two diodes in place of the 5Y3. The hole in the chassis for the rectifier tube was blocked off with a plate. I'm not sure if the first filter capacitor value was increased or not. I think they bumped it to the 40/30/30 cap can that the M10 used, but I'm not sure. If anyone has an original 214 with an SS rectifier, please contact me.
Eventually, the 214 became the 96-10041,
The Tonemaster 381 was based on the 280, and then later, the 480. Evidently, Gasparetti had no use for reverberation on accordion amps, because whne the 480 adopted reverb, he had Estey build the 381 as a 480 stereo amp without reverb.
Imperial contracted with the Italian instrument maker, Crucianelli, to build accordions, guitars, and basses under the name "Tonemaster". The instruments were very well built and maintain their playability 50 years later.