Ace Electronic Industry Inc (normally known as Ace Tone) was a division of Sakata Shokai Limited of Osaka, Japan. They produced a portable organ(the GT7) and several drum machines. There is a relevant connection between Hammond and Roland here somewhere, as AceTone products are too similar to Hammond and Roland products. The GT7 organ was a clone of the Hammond X5, and the Rhythm Ace FR-2L is a clone of the Auto-Rhythm from Hammond and rumour has it that AceTone became Roland. A further confusion set in because in the UK Ace Tone products were distributed by Bentley Pianos in Woodchester, Glos. who always stuck their badge on the products, and sometimes Ace Tone drum machines are known as the Bentley Rhythm Ace rather than the Ace Tone Rhythm Ace.
Ace Tone was the predecessor to Roland. They made quite a number of combo organs during the 60's, and are one of the more well-known combo organ brand names. They may also be related to Whitehall - look at the stop tabs on the TOP-5 and compare them to the Whitehall 6640 - they're almost identical. I understand that the vibrato on these is excellent. Ace Tone also had a relationship with Hammond. They were largely (or, perhaps entirely) responsible for the early portables, the X2 and X5. You can read more about the history of Ace Tone at the Keyboard Museum. Here's some more historical info, as ferreted out by fellow Combonaut, Micke L: "First of all, Ace-tone was just a tradename used on the various electronical organs and NOT a company (although I read that back in 1974, Kakehashi re-marketed the Roland SH-3 monophonic synth under the Ace-tone name! so apparently he still owned the right to the name)
Ikutaro Kakehashi was not only the founder of Roland (in 1972), 12 years before that he'd already founded Ace Electronics Industries in Osaka. He was to be responsible for the development and design of the Ace-tone combo organs but eventually left the company in 1972 (the very same year he founded Roland). But before that, in 1968, he'd founded Hammond Japan, a joint-venture of his Ace Electronics and the Hammond International Company. From what I understand this company built and released the Ace-tone GT-7 portable organ as early as 1971, some 3-4 years before they built the Hammond X-5 organ for the Hammond company in the states! (which in fact would mean that the Hammond X-5 was sort of a "copy" of the GT-7 instead of the other way around...) but by then Kakehashi was running the huge Roland enterprise.
After Kakehashi had left Ace Electronics in '72, the firm continued to build organs and synths, though I don't know whether these as well were marketed under the Ace-tone name, but I don't think so."
According to Peter Forrest, the first AceTone organ was a spinet, with model number TO-1. He suggests that perhaps "TO" stood for "Transistor Organ". I'll take it one step further, and suggest that "TOP" stands for "Transistor Organ, Portable". Sounds good, anyway. The TOP models seem to be of two different families. The TOP-3 was available as early as 1965. The TOP-5, 7 and 8 look very similar, and probably came out shortly afterwards. Then in 1968-69, the TOP-1 and TOP-9 were introduced. The TOP-6 probably came out around the same time, but didn't appear in the 1969 brochure.
There was an Ace Tone TOP-1 in the movie "Godzilla and the Smog Monster". It's in a Japanese hoedown (?!) scene. (thanks, Jeffree, for this tidbit) And there might have been one in Alex's living room in the movie "A Clockwork Orange" (thanks to Barry for this one)