Thompsonic TS-33 - stereo electronic keyboard   digital squarewave keyboard with many sound controls & great accompaniment

This quite rare squarewave keyboard is one of the most interesting MC-3 successors, because it has real 8 note polyphony, a very simple synthesizer and permits more manual control over the sound than other keyboards based on the DSG-MC-3 soundchip. IMO it is the most professional behaving instrument in its hardware family; also the great accompaniment has many variations.

(Note: This keyboard sounds great, but don't buy one of these so far your only intention is to get a keyboard with faithfully imitated natural instrument sounds. Remember, this is a squarewave instrument and though many of its sounds sound not even remotely like what is written on its buttons, though bought with wrong expectation it may disappoint you.)

main features:

The bizarre case style reminds rather to 1950th aeroplane or soviet military technology than a music keyboard. This is its synthesizer section; the 4 "wave form" icons to the left are totally nonsense; genuinely these should be plain squarewaves with different pulsewidths. This is the PCB; note the 2 identical DSG sound chips right to the CPU.



The control panel design and case colour of the Thompsonic TS-33 resembles much the Fujitone 6A, thus it was likely a close predecessor although it had no FM sound, but it has already the row of 4 metronome LEDs (1 red, 3 green). Like with the 6A, unfortunately also here the grey on grey control panel writing is very badly readable under non- optimal lighting conditions. I bought my specimen in very poor and dirt stained condition on a flea marked; someone apparently had replaced the original internal speakers with wrong ones (brand "Tonsil")  those rumbled loose around in the case because they didn't fit to the original screw holes. One speaker is even oval instead of round, but I hotglued them to their intended place. Also the battery compartment cables were missing and the "A.B.C volume" potentiometer was broken.

The sounds and operation of the TS-33 behave basically very much like my Letron (MC-3, see here), thus I will describe in the following only the different features of the TS-33.

Unlike the MC-3, the TS-33 has only 8 OBS preset sounds, but the so-called "synthesizer" provides 16 sounds (including louder versions of the 8 preset ones). Although this wannabe "synthesizer" only permits to combine 4 OBS preset waveforms with 4 OBS preset volume envelopes (i.e. 16 sounds in total) and thus does not deserve this term at all, it provides a nicely intuitive realtime control by its OBS buttons, those also affect held notes. Also the transposer and pitch buttons can be used this way. When the synthesizer mode is enabled (by pressing the "synthesizer" button), the produced sound is independent from the selected OBS preset sound button. Like most buttons on this instrument, also the "synthesizer" button can be toggled in realtime to switch held notes back and forward between the current preset and the synthesizer sound. The icons above the synthesizer "wave form" buttons are nonsense; they show something that looks like a triangular waves with different amplitudes, although they in reality change the pulse width of the squarewave tone.

The sustain button adds a quite long release phase to the notes which makes the "piano" sound ignore the key press duration. The vibrato from the vibrato button stops in the release phase of sustained notes. When sustain is switched off, all sounds stop almost immediately after releasing the key. The "stereo" button switches the stereo chorus on and off, which adds a different sort of vibrato to the sound (that doesn't stop after key release), similar like a rotary speaker simulator. But this one is not based on analogue panning like with other squarewave keyboards, but it is generated by the soundchips and also halves the polyphony, likely because it doubles all main voice notes to generate the chorus effect. Instead of panning there is only a sort of spatial stereo.

A bit strange is that pressing the "stereo" chorus button always switches off the synthesizer (despite its LED stays lit), although the synth can be re-enabled with its button while the chorus stays active. Also the normal (faster) vibrato stays disabled so long the stereo chorus is active. The synth also sporadically turns off the same way (typically after a few minutes) without any obvious reason; it might be that capacitance effects by missing pull-up resistors on the data lines from the CPU to the 2 DSGs cause data mess that in certain situations overwrites the current timbre data in internal sound chip registers and thus resets them to default, but I haven't verified this yet. Strange is also that unlike the preset sounds and rhythms, the "synthesizer" can not be enabled during the demo musics (despite it provides basically only a set of 16 preset sounds and thus does nothing complex).

The base drum of the TS-33 sounds much duller and thus more realistic than on my other DSG based keyboards (likely it is muffled by capacitors). Unlike the MC-3, the 12 OBS rhythms here have each an intro, fill-in and ending that is also accompanied by the accompaniment, and even 2 different accompaniment styles (usually a simple and a complex one) can be selected and toggled by the "variation" button. Similar like with early Casio squarewave keyboards, the bass and chord voice can be cycled through 4 timbres {piano, guitar, synth 1, synth 2} by a button, which also works in realtime with held chord notes (synth 1 & 2 are organ tones without sustain). And thanks to its 2 DSGs this instrument also permits reasonable main voice polyphony during accompaniment, and the great accompaniment still permits versatile play techniques and accepts non- chord key combinations like the MC-3. The only lacking feature in comparison to it is the missing "manual bass" button. Also the lots of red LEDs are gone, but instead it has the nice 4 LED metronome row that flashes in complex patterns during rhythms.

This instrument was also released as "Fujiya MC-33" (seen on eBay) and MC-33 (by Medeli?), thus the genuine name of this hardware class is "MC-33", which corresponds to the CPU type label. Also a version with the brand First was released. With its 8 note polyphony and many changeable sound parameters this seems to be the yet most professional squarewave hardware I found among MC series keyboards (originally created by Medeli?). The only still unprofessional feature is the rather annoying battery warning, that plays 2 notes after 100 seconds of silence (also with AC- adapter).
Condor MC-9000 (eBay photo)
Another instrument of this hardware class is the large fullsize keyboard Condor MC-9000 (I asked the eBay vendor about demo melodies etc.), which has detachable speakers and was also released as Monacor MC-9000, Trend Line MC9000, Tristar MC9000 and Kamosonic F5 (or S5?). Also a GPX version was made. An eBay vendor claimed that the Trend Line version came out around 1993. 
Bizarre is that an MC-9000 variant with smaller, non- detachable speakers was released as Fujitone 6B (case design like Letron MC-103, button style like Letron MC-3), which is totally different from the "real" (later?) Fujitone 6B model (aka MC-6B) that employs the same FM hardware class like my Fujitone 6A; it was also released as HBATEC MC-9A. Likely a direct successor of the Thompsonic TS-33 hardware class was the Letron MC-103 (with FM sound, but almost identical operating concept).

 removal of these screws voids warranty...    
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