Testron CL-60910, Elta HS4242
Testron CL-60910
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CL-60910
(squarewave keyboard with warm C64 sounds &
great accompaniment) |
This instrument sounds very similar like the Letron
MC-3, but has a much warmer timbre and a wonderful responsive and
versatile programmed automatic accompaniment. The case is bronze colour
and has the German label "ELEKTRONISCHES KEYBOARD" ("electronic keyboard").
It was also released as Elta KE-5 and Elta CL-6091. A black
case version was released as Plantron DP88, as Pantera PM88
and as Eastec ER-460 (seen on eBay).
(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:
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49 mid size keys
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polyphony 4 notes (only 1 note with accompaniment, 3 notes with manual
bass)
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stereo (2x 2W amp with 10 cm speakers)
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combined rhythm/ accompaniment fader
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12 OBS preset sounds {piano, trumpet, guitar, accordion, harpsichord, oboe,
music box, violin, clarinet, organ, electric piano, funksynth} (squarewave
with digital envelopes)
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12 OBS preset rhythms {pops, country, big band, disco, latin, slow rock,
reggae, bossanova, march, rock'n'roll, 16 beat, waltz}
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5 percussion sounds {base drum, tom, snare, open and closed hihat} of unique
electronic style.
base & tom |
= low & higher squarewave blips |
snare |
= shift register noise |
open cymbal |
= unique electronic metallic timbre (low- res waveform sample??, or
2 mixed squarewaves?) with truncated decay and audible end click. |
closed cym. |
= dto. with shorter envelope |
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auto- accompaniment in "single finger" chord or "fingered" chord mode (when
rhythm off = manual piano chord keyboard split).
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manual bass keyboard split (e-bass sound instead of accompaniment)
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sustain, vibrato and rhythm fill-in buttons
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transpose buttons (-11 semitone steps, works only in "fingered" or "single
finger" chord mode and affects only main voice)
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tempo buttons (14 steps?)
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lots of red, round status LEDs
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demo melody "For Elise" (bad sounding monoto)
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main CPU "NEC D7507CU, 234 8735AY003" + separate squarewave soundchip (crystal
clocked). This sound IC sounds and looks like the "Letron" DSG, but it
is a genuine Yamaha YM2163. It has digital envelopes (with a little zipper
noise and end click) and the following pre-mixed sound output lines:
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main (4 voices or 1 voice with accompaniment on)
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accompaniment (3 voices = organ- like tones without envelope)
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e-bass (monophonic)
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snare or open hihat or closed cymbal (monophonic)
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base or tom (monophonic)
All sounds beside snare and hihat are squarewave based (with different
pulse widths and envelopes) and sound much like a C64. The soundchip apparently
internally re-assigns the same tone generators to different outputs due
to in accompaniment mode only 1 voice remains at the right keyboard section
for melody play.
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jacks for AC- adapter, headphone, cinch L & R outputs
modifications:
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2 separate pots for bass and chord volume added. Important is to place
them in the line of given resistors (cut a trace for this). Don't choke
the signal current by shorting AC- wise against ground because this would
destroy the unique warm analogue timbre of this wonderful instrument.
It would make sense to replace the crystal with a coil/ capacitor oscillator
to make the instrument tuneable.
notes:
The CPU is made by NEC, those also manufactured most of the early Casio
keyboard ICs. Unlike the Letron MC-3,
the Testron CL-60910 always uses a piano- like envelope for chords.
Depending on the rhythm volume slider position, the chord distorts at the
beginning, which creates a warm sounding sort-of dull fading "wah- wah"
filter envelope. The accompaniment has very interesting arrangements those
vary depending on how many chord keys are pressed, and it does not restrict
you to play establishment's standard chords. Thus e.g. the "country" accompaniment
can make great disharmonic horror/ thriller music by pressing adjacent
keys.
When rhythm is off, this instrument also provides a sort-of key split
feature; in "manual bass" mode you can play a monophonic e-bass at the
left (accompaniment) keyboard section and the 3 note polyphonic main voice
at the rest, while in "fingered chord" mode you can play a 3 note polyphonic
piano sound to the left, and the monophonic main voice to the right. The
vibrato is unusually fast. Unfortunately all tones of this crystal clocked
instrument are detuned by about -0.75 semitones and there is no trimmer
to adjust tuning. Like with many old keyboards, the 12 OBS sound buttons
can be also pressed while keys are held down without stopping their notes,
thus theoretically they may be usable as a realtime sound control for arpeggiator-
like timbre changes. Unfortunately the CPU polls the buttons only with
about 4 Hz, which makes them respond much slower and less precise than
with the Letron, and also the silicone rubber buttons are a bit
awkward to press quickly.
Apparently the direct successor of this instrument was the Elta
KE-6. A possible predecessor was the ABA-88.
Elta HS4242
This is a simplified and shorter variant of the Testron
CL-60910. I am not sure about the original name of this keyboard,
since the main model plate is missing and there is only the brand name
Elta
and a small paper sticker "HS4242/89" at the bottom; the "/89" likely indicates
that it was released in 1989.
This instrument has only each 8 preset sounds & rhythms, but the
same lovely accompaniment like the Testron, although the bass sounds
less impressive since it uses here a very similar squarewave timbre like
its main voice. Likely a separate bass sound filter was omitted here to
reduce cost. Also the sound chip is not a genuine Yamaha one.
different main features:
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37 mid size keys
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only 1 speaker (mono)
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only 8 OBS preset sounds {piano, accordion, trumpet, guitar, music box,
harpsichord, oboe, clarinet}
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only 8 OBS preset rhythms {pops, big band, disco, country, rock 'n' roll,
16 beat, waltz, march}
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no rhythm/ accompaniment volume control
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no sound/ rhythm indicator LEDs
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bass sounds simpler and less warm (likely by the lack of a separate filter)
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no demo button
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CPU= "NEC D7507CU 234, 8734AY007, Japan" (40 narrow pin DIL) + sound
chip "CR-3163, 8932A" (24 pin DIL)
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jacks for AC- adapter & headphone
eastereggs:
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Due to the same CPU, the omitted OBS preset sound, rhythms and demo buttons
can be certainly re- added as matrix eastereggs.
removal
of these screws voids warranty... |
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