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)

TOP-1 TOP-3 TOP-5 TOP-6
TOP-7 TOP-8 TOP-9 GT-7

TOP-1

The entry-level model from the 1969 series.  A sharp looking organ, the TOP-1 seems to be the more common of this later series.

Controls: 

The Bass section may be switched to extend the treble section (with the Double Bass tab, I think).  The Treble tab adds brightness

1969 List Price: $410.  Check out the 1969 brochure page below.


TOP-3 aka Phenix

Not very flashy, with its grey painted exterior, but a decent looking starter organ.  In a 1965 ad, it was billed as simply "The ACE-TONE Portable Electronic Organ".  Retail price: $385

Controls: 

Check out the unusual system for storing the legs:


TOP-5

One of the more common combo organs is the AceTone TOP-5.  A fairly limited instrument in many ways, it does seem to have the bare-essentials required of a good combo organ.  

Just read these glowing reviews from two satisfied TOP-5 owners:

"I think [the TOP-5] nails a great combo sound for recording and performance. Granted, if ... you're looking for a lot of variability (if you were going to play it all night, say, and wanted lots of different sounds for lots of different songs), then it would probably be too limited. But if you're looking for a great, strong, clear combo sound, then look no further than the Top-5.  On top of it's sound it's also very small, and also reliable. I bought mine and it worked then and works now, and I can't say that about very many of my instruments. It's the Toyota of the combo world: not too much glamour, but when you get in, it starts and gets you where you're going."

"The more I record, the more I find my Top-5 is my organ of choice... The Top 5 may not sound 'Good' by organ standards, but I find in the context of a mix, it more often sounds "right". The few sounds that it can produce, are all the sounds that one needs...I LOVE MY TOP 5!!!"

Controls

Now compare the TOP-5 stop tabs with those of the Whitehall 6640:

TOP-5: Whitehall 6640:

They just look too much alike


TOP-6

Sort of a cross between the TOP-1 and TOP-9, but with sliders instead of tabs, and only Flute and String voices. It did not appear in the 1969 brochure, with the TOP-1 and TOP-9, and may have been introduced later.

Controls:

(thanks to Jim for the great pictures!)


TOP-7

The TOP-7 adds multiple footages (16', 8' and 4') over the TOP-5.  
(Thanks to the DDCT Ranch for the photos and info)


Controls:

The first two tabs, labeled simply "Flute" and "String" are rather unusual.  They produce the same voice as the other Flute and String tabs, both in a 16' footage, and both with Sustain added.  Oddly enough, however, they do not sound at all for the first 19 keys.  Only the 2nd "C" on up are affected.  Very strange. (Thanks to "lotuz" for this tidbit)

TOP-8:

Top-o-the-line, the TOP-8 adds two Sustain voices (or maybe two decay times, I don't know) to the TOP-7's features.  I don't know if the Sustain tabs operate in the same manner as the TOP-7.

Thanks to Blair for the following information on the TOP-8.

Controls: 

The bass section is fixed, cannot be switched to treble.

Here's a review from a TOP-8 owner:

"...the two sustain tabs and the vibrato are the most distinctive features -- the overtones from the sustains practically create their own music if you pump the woodie through an old Fender or Musicman tube amp and let 'em rip -- really amazing. The vibrato on most AceTones I've used is just the best ever, when it's got separate speed and depth controls. They basically just went too far in both those parameters, so you can get unearthly howling siren-stuff. Fun for the whole family, and the neighbors too.  The Top-8 is also much much more flexible than the Top-3 and Top-5 (the other two AceTones I'm familiar with) tonally, for a couple reasons. You've got a selection of footages on the tabs -- 16', 8' and  4' -- and a wider range of sound options.  AceTones can tend to have a sort of "honking" sound, endemic to the cheapo combos, that's limiting to what you can do as far as grittiness; the Top-8 has the grittiness, though. Combining all the String footages with the 16' Flute, and ignoring all the other reed/woodwind hoohah, gives a really intense, cutting sound with lots o'grit. Also, using just the 8' Flute tab with the two sustains gives you a unique early-synth staccato kind of sound.   I'm not going to try to describe it, although I remember someone describing it as "drops of water falling into a pool" or something equally great. Obviously, for more traditional combo applications (i.e. retro garage stuff), a Continental or Farfisa is what you want -- there's no denying that those are as good as it gets within the genre. But for a weirdo like me ... the Top-8 offers more opportunities to mess with tones and minds. Rock and Roll, and all that."


TOP-9

Definitely the "TOP" of the line.  Tilt stand, 61-note keyboard, 18-note bass section, switchable to extend the treble section. 16', 8' and 4' treble voices, 16' and 8' bass voices, optional bass pedals, and sustain!. A real hummer!

Here's some additional description, courtesy of Barry Carson: 

"It was advertised in October of 1968.  It had 61 keys, 18 of which are gray and could be used 'to produce both bass and normal sounds plus crush cymbal sounds if desired'. It really says 'crush', whether they spelled 'crash' wrong or if it really sounded like a crush cymbal, I cannot say. The other keys are regular white ones and played flute, 'cello, trumpet, and string sounds at 4', 8', and 16'.  It had a 'bass attack' feature, and it looked kind of like a FAST 4 except that it swiveled up and down like a Farfisa Professional or Fender Contempo.  A bass pedalboard was available. It didn't say how much it cost, but that it was priced 'realistically'"

1969 List Price: $725


GT-7

Looks like Ace Tone's answer to the Hammond Porta-B, though I'm told it's actually set up more like a T-100. I wouldn't even consider this a combo organ (a bit too much "wood" for my tastes) except for all those pretty colored stop tabs across the top, and, of course, the extra cool Ace Tone name.

The following historical info was provided to me by the owner of the organ pictured:

"The AceTone GT-7 was made by Sakata Shokai (Sp?) in Osaka Japan. Shortly after it was marketed in the U.S. Hammond started marketing combo and portable organs made by Sakata Shokai with the Hammond name. The X-2, X-5 and B-200 were all japanese made. I have obtained parts for my organ both from Hammond and directly from Japan. About that same time the AceTone organs disappeared from the U.S. market. I presume this could have been part of the agreement with Hammond. There were several relatively nice spinet organs made with the AceTone name that had some nifty touch controls. I don't remember for sure but I think they may have had Hammond-like drawbars. I saw them at a dealer in Dallas in the early 70's."