Kawai KMA-37

Electronic Organ

This little keyboard is peculiar. Essentially, it has some of the basic features of many electronic organs (two tone settings, vibrato, and basic rhythms), but a small range of 37 keys that makes it smaller than any typical "combo organ" keyboard, as well as most home organ manuals. I think it is possibly a late 70s-early 80s model, based on such things as the fake wood veneer and metal case materials, analogue chip-based circuitry, and buttons resembling those of larger Kawai home organs of the early 80s. It seems as well that this is a very uncommon unit, since I have found only one other reference to it online aside from those I have made myself (see the Link section). I have even contacted Kawai, but it seems they are just as confused about its existence as I am.

Features

  • 37 full-sized keys (C4 to C7 / 3 octaves + semitone)
  • completely polyphonic (all notes can be played at once) analogue tone generation
  • 2 tone settings with on/off buttons {flute, organ}
  • non-adjustable vibrato with on/off button
  • 5 rhythm patterns from built-in "rhythmer" unit {metronome, 2/4, 3/4, 4/4, 6/8}
  • tempo control for "rhythmer"
  • volume controls for "rhythmer" and overall volume
  • single built-in oval speaker
  • 2 1/4" output jacks {ext out., headphone}

Trivialities

  • 8 single-sided PCBs, using all through-hole components
  • multi-chip design, featuring
    • 3 TI TMS3615-25NS tone generators for 13 frequencies each (28-pin shrink DIP)
    • Sanyo LA4230 6-8W power amplifier (12-pin SIP)
    • 7815 and 7915 positive and negative voltage regulators, respectively (+/- 15V)

The Hardware

The build quality is surprisingly good, especially for a unit that would have likely had comparatively limited functionality even when new. The casing is made of mostly wood and metal, with the metal top cover being held on by 8 screws driven into wooden mounting blocks. The likely reason for having so many screws is due to a carrying handle mounted to the metal cover on the back of the unit. On the back can also be seen the builder's plate, the two outputs, and two peculiar rectangular holes (what would these be for?) The "EXT. OUT" does not interrupt the internal speaker, while the "HEADPHONE" output does. Why this unit would have both external and headphone outputs is a good question... what would have been the intended purpose of this keyboard?

More peculiarities can be found by looking at the bottom of the instrument. Towards the front, there are two brown plastic pieces mounted in a similar horizontal arrangement to the rectangular holes in the back. These are slotted and would appear to have accepted metal mounting "hooks", perhaps? Near the back and in the middle horizontally, there is a metal bracket that looks like it could have slotted onto a bar or something. It seems that this unit would have probably had a very specialized mount, perhaps attaching it to a larger unit?

Removing the eight screws and carefully moving the metal cover out of the way reveals the insides:

The small oval-shaped internal speaker can actually produce a pretty decently loud output, thanks to the Sanyo LA4230 6-8W amplifier chip. However, at least on my unit, there's a fair amount of buzzy distortion at high volumes, so I generally just use the headphone output (which cancels the speaker) through an amp. The internal wiring is very neatly arranged and tied with clear plastic strips, and most connections between boards are made with plug connectors, which would make removing (or replacing) boards during servicing quite easy. Of course, finding replacement boards today is impossible, considering finding another of the same instrument is impossible. Luckily, though, the boards feature a lot of easily replaceable discrete components. Even the generator chips seem to be potentially available online: three TMS3615-25NS capable of generating 13 frequencies each.

Again, there are still many confusing aspects of the unit. It is basically a 37-key electronic organ with very limited tone settings and basic rhythm, with excellent build quality; quite an odd combination of features, really. What was the original intended purpose of this keyboard? It's too limited in tone and range for most professionals to perform with. Perhaps it was made as an inexpensive practicing unit, but if so, why such a high-pitched range (C4 to C7), and why such high build quality? Also, what about the unusual mounting points on the bottom, and the rectangular holes in the back? These questions may never be answered, to the inevitable disappointment of millions...

The Sounds

The "flute" tone is relatively mellow and uses triangular waves, while the "organ" tone is brighter and closer to a sawtooth/ramp shape. Having both tone buttons pressed in at once combines the two. The vibrato is very basic, with a medium frequency, but with not a high amount of "depth". In fact, it's easy to forget that you've turned on the vibrato once it's been on for a while, since it is so subtle.

The "Rhythmer" is a neat little rhythm unit, also very simplistic. There are 5 on/off buttons for selecting the rhythm pattern: metronome, 2/4, 3/4, 4/4, and 6/8. Buttons to the left override buttons to the right, however the 6/8 button doubles the speed of all rhythms no matter what. Each beat consists of a burst of noise controlled by a simple volume envelope (sounding similar to a snare drum), with the downbeat also including a "blip" of low frequency content, adding a sound similar to a bass drum.

This thing really sounds great when used with some overdrive/distortion. I especially like to use it with my homemade "Valve Caster" tube overdrive, which has fairly low gain and gives a "buzzing" sound, but the KMA-37 can also produce interesting sounds with high-gain distortion such as that produced by the Hardwire TL-2 pedal.

It has been used (mostly in conjunction with the Valve Caster or Hardwire TL-2 distortion, among other effects) in numerous JCS releases from the group S.F.A.T.B.H.S., including The Day We Saw Toast On Jeasus, Third, Third II, Vivaldes Hit's Volume II, Colonel Salt's Bandly Bands Band Band, Songs From, and The Age of Nusic. As well, it has been used with overdrive and wah on Jesse Acorn's release Demos, or perhaps not...

.:Music Technologies Group:. - Southern California Music, MIDI and Electronics - The only online reference to the unit I've been able to find. Basically, some guy repaired one in 1990.

If you notice any errors or have additional information that you would like to add, please contact me!


Last Updated: 7/21/2016