GPM MC-5000

GPM

(FM keyboard with accompaniment & programmable rhythm)

This keyboard is another strange MC-3 successor. Despite it has the same case style and button layout like an MC-3, it has no simple squarewave sound anymore but a 2 operator FM sound chip with quite warm and noble sounding timbres.

Apparently this thing was technically a close predecessor of the great Fujitone 6A (aka MC-6A) because the sound is very similar. But the operating concept is much like the MC-3, and it still has the great programmable drum pattern ("custom drummer"), although this one is a bit more restricted than on MC-3. The percussion of the MC-5000 is made from 5 typical electronic sounding FM drums. The MC-5000 has 24 preset sounds and 16 preset rhythms (both selected through semi- OBS buttons those each alternatingly select between 2 sounds / rhythms when pressed twice), and the rhythms have intro, fill-in and ending, and each 2 accompaniment variations. The accompaniments are nicely arranged, although they sound fairly establishment and contain nothing really unusual. At least they accept also disharmonic key combinations and not only those few ones considered "chords" by the establishment. The sounds are 2 operator FM timbres those sound quite warm, smooth and noble, although not necessarily realistic. This way the sound generally reminds more to classic expensive home organ or e-piano timbres than to the rough and noisy sample stuff found on cheap modern tablehooters.

Important is not to confuse this instrument with the MC-3000, which has the same case but contains normal MC-3 hardware.

main features:

49 midsize keys (very responsive)
polyphony 9 notes (only 6 with rhythm, only 3 with accompaniment)
stereo (quite loud 10 cm speakers with some bass)
24 semi- OBS preset sounds {piano, clarinet, bassoon, mute trumpet, violin, duck, metallic synth, jazz organ, bagpipe, flute, pipe organ, horn | e. piano, oboe, harmonica, slap bass, cello, synth brass, chimes, e. organ, handsaw, wood brass, tuba, saxophone} (each button selects 2 sounds alternatingly)
16 semi- OBS preset rhythms {rhumba, waltz, march, disco, pops, swing, tango, big band | bossanova, jazz waltz, rock 'n'roll, 16 beat, salsa, reggae, samba, slow rock} (each button selects 2 sounds alternatingly)
rhythms with optional intro, fill-in & ending pattern
main volume slider
separate slide switches for rhythm- and accompaniment- ("A.B.C. " = auto bass chord) volume (each 5 steps)
5 plastic drumpad buttons
5 percussion sounds {closed cymbal, open cymbal, conga, snare, base} of classic electronic FM style
programmable(!) rhythm pattern (up to 16 steps "custom drummer")
auto- accompaniment in single finger chord or fingered (=normal) chord mode (manual chord keyboard split with rhythm off). (Chord sound depends on selected rhythm.)
variation button (alternative accompaniment pattern)
sustain & vibrato buttons
transposer +/- buttons (-12 semitone steps)
tempo +/ - buttons (16 steps)
lots of red status LEDs
sound generator based on 2 operator FM
CPU "SC-MC-5, 142205" (42 pin DIL) + separate FM sound chip "MC 9003" (24 pin DIL, likely same like in Fujitone 6A)
demo melody "Aloha Ohe" (cycles through multiple sounds & rhythms)
jacks for AC- adapter, headphone and L & R outputs

This was the broken amplifier IC KA2206.

notes:

Like the Letron MC-3, also the GPM MC-5000 has a lot of red status LEDs to indicate the selected preset sound and rhythm, although these ones are round, small and quite dim in comparison to the rectangular Letron ones. But there is no LED to indicate which of the 2 sounds or rhythms per button is currently selected, which limits their use. Like with a classic Hammond organ, the keys are very responsive, thus you can easily play glissandos on them. Thanks to the separate sound chip, the MC-5000 can be certainly easily modified with the same simple FM synthesizer upgrade like my Fujitone 6A. (I haven't analyzed the hardware further yet.)

Attention: When I bought my MC-5000 on a flea market, the power amp IC ("KA 2206") was toast, thus the instrument played only through 1 speaker while it hummed badly and the IC ran very hot. After replacing the thing, it played perfectly. Possibly a kid had just plugged the AC- adapter into one of the speaker jacks and fried the amp this way, but this instrument generally plays very loud already at only 1/3 of the volume slider way, and the amp IC is powered by the full voltage of the AC- adapter, thus I recommend to set the power supply voltage not higher than necessary (at medium volume only 3V on my unregulated adapter) despite the instrument has a "DC 9-12V IN" label at the jack.

The preset sounds of this instrument seem to be a real subset of the Fujitone 6A sounds (see there). They have the typical 2 operator FM timbres and most are not programmed really realistic but resemble more classic home organ or e-piano timbres since most have very simple envelopes or contain unrealistic vibrato. But they don't sound unpleasant but have quite warm and noble sounding timbres (less rough than my Yamaha PortaSound FM keyboards) with nice bass range. Unfortunately the MC-5000 features none of the really freaky tekkno noises of the 6A, but mainly acoustic instrument imitations. But there are at least some wahwah- like synth organ timbres ("metallic synth", some brass sounds); also "duck" is no water bird voice but a synth brass sound. The "bagpipes" sounds not at all like expected, since its sonorous woody tone has a too slow attack rate and a strong tremolo (4Hz). The "handsaw" is a spring- like resonant metallic timbre that slowly fades silent. The "synth brass" has a slow attack phase and fades silent. The "chimes" has a thin metal timbre (like a clock chime) with long sustain. The "piano" resembles a Rhodes while the "e. piano" has a brassy timbre, sounds duller and has vibrato. The vibrato of the "vibrato" button mixes with the given one of in some timbres (both have different speeds), and also intensity varies with the actual preset sound, which makes nice textures with some timbres. The "sustain" button sets the sustain (release phase) to a fixed duration of 1 second, which can be shorter or longer than the default sustain duration of that sound. Great is also that (like most FM keyboards) the timbres are time- dynamically playable, i.e. the timbre of notes changes depends on how long a key is pressed, which provides a relatively expressive playability despite the keyboard is not velocity sensitive. Unlike with the MC-3, the preset sound buttons of the MC-5000 are no really good realtime sound control, because they always stop held notes when sounds are switched, and only a very quiet sustain stays audible for a second. Due to its separate FM sound chip, also this instrument can be likely easily modified into a simple FM synthesizer, like I did with the Fujitone 6A (and thanks to the programmable rhythm it may be even more interesting to change the percussion this way).

The percussion has the typical electronic FM timbre known from the OPL3 "MIDI synth" of early PC soundcards, which is different from the MC-3 percussion. But like the latter (see there), the MC-5000 has still the same great "custom drummer" feature to program your own drum patterns. Unfortunately a small but annoying flaw makes this one way less versatile, namely the user pattern always selects here the accompaniment of the preset rhythm it was programmed with, thus you can not intuitively switch to a different accompaniment anymore, but only select the preset rhythm with the desired new accompaniment and then manually re- enter the entire user pattern again, which is unacceptable for live performance. A strange detail is that without rhythm the polyphony reduces by 2 channels as soon any drumpad is pressed; to achieve full polyphony again, you have to press the "percussion off" button (same like "demo", plays demo when pressed twice). Such a "percussion off" button exists also on the Fujitone 6A.

The accompaniments are nicely arranged, although they sound brave and fairly establishment and contain nothing really unusual. Interesting is only that there is a "variation" button, with that you can switch back and forward to a second (usually more complex) accompaniment pattern (e.g. with additional arpeggio). Such a button exists on the similar looking Penrod AJ-430, although the latter has squarewave sound (like MC-3) and different patterns. The Fujitone 6A otherwise has no variation button. The individual intro, fill-in and ending patterns (the latter 2 with accompaniment) are a nice detail, although also establishment. Fortunately the fingered accompaniment accepts also disharmonic key combinations and not only a few establishment chords.

Regarding the CPU type label, also an MC-5000 variant called "MC-5" may exist, which appears to be the genuine name of this hardware class (e.g. MC-3 keyboards (like Letron MC-3) also have "MC-3" in their CPU name). A technically direct successor of the MC-5000 was released as Fujitone 6A (aka MC-6A), which has a spacey case design and 100 FM sounds with many great grainy tekkno noises. Another close successor was the fullsize Letron MC-103 (very similar accompaniment).

*removal of these screws voids warranty...*

	back