via
this auction"Up for sale is a rare Maestrovox tube synthesizer keyboard instrument, one of 17 known to exist, and a unique model. These first went on sale in 1952. Much information on these, including schematics, can be obtained by visiting the following website, which belongs to the granddaughter of the inventor of the Maestrovox:
http://www.debbiecurtis.co.uk/id99.html
This Maestrovox is a special instrument because the keyboard's facade (rocker switches, entirely black paneling, etc), is imitative of the Clavioline, while it still maintained the same speaker/ amp cabinet as the regular Maestrovox Consort model. It has mounting stand. I think the way this Maestrovox was supposed to work is that you place the speaker/ amp cabinet on the ground, which brings the keyboard to playing height if you are in the sitting position. Quite a unique, cool set-up.
This Maestrovox is cosmetically in very good condition. The keyboard itself is in excellent condition. The speaker/ amp cabinet is missing its original grillcloth (a green replacement grillcloth has been mounted to the front with thumbtacks), and the tolex if pealing in a few places.
This Maestrovox MIGHT be completely functional, but my power converter does not provide enough wattage to adequately test it. It runs off of 220V/240V, because it was invented in Australia, and the only converter I could find locally that would support that voltage was at Radioshack, and it only could provide 44W of power, which is only enough for a small appliance (I have included a picture of the converter I used to test it). So, because of that, the Maestrovox could not be properly tested. From my albeit insufficient testing, the upper two octaves definitely worked, and the lower octave did not work. That is likely a simple fix because the Maestrovox, like the Clavioline, used three-octave dividers to derive all the pitches from a single top-octave tone generator. The sound is somewhat weak, which is also likely due to the insufficient wattage. It could even just be a bad tube, or perhaps the lack of power resulted in only two of the octaves working during testing. Why did Maestrovoxes, Claviolines, Ondiolines, and Solovoxes have only 36 notes? Because adding a 37th note would have required a fourth divider. This Maestrovox has an octave switcher with three positions immediately to the left of the rocker switches, and two tuning knobs on the left and right side of the keyboard front. The same thing happens one each octave setting: the lower octave of the keyboard does not play anything. With the schematics, it should be very easy to bring this to perfect functional condition, if it is not functioning perfect already when properly powered (I'm not able to test it sufficiently, as described below).
Further information on the history and function of portable and mountable tube synthesizers (namely the Clavioline, but also the Maestrovox, Ondioline, and Solovox) can be
found hereAnd
another Maestrovox-related webpage"
via this auction
via this auction
This Maestrovox MIGHT be completely functional, but my power converter does not provide enough wattage to adequately test it. It runs off of 220V/240V, because it was invented in Australia, and the only converter I could find locally that would support that voltage was at Radioshack, and it only could provide 44W of power, which is only enough for a small appliance (I have included a picture of the converter I used to test it). So, because of that, the Maestrovox could not be properly tested. From my albeit insufficient testing, the upper two octaves definitely worked, and the lower octave did not work. That is likely a simple fix because the Maestrovox, like the Clavioline, used three-octave dividers to derive all the pitches from a single top-octave tone generator. The sound is somewhat weak, which is also likely due to the insufficient wattage. It could even just be a bad tube, or perhaps the lack of power resulted in only two of the octaves working during testing. Why did Maestrovoxes, Claviolines, Ondiolines, and Solovoxes have only 36 notes? Because adding a 37th note would have required a fourth divider. This Maestrovox has an octave switcher with three positions immediately to the left of the rocker switches, and two tuning knobs on the left and right side of the keyboard front. The same thing happens one each octave setting: the lower octave of the keyboard does not play anything. With the schematics, it should be very easy to bring this to perfect functional condition, if it is not functioning perfect already when properly powered (I'm not able to test it sufficiently, as described below).
