The preset sounds are made from multipulse squarewave with simple capacitor envelope, thus despite most don't sound realistic at all, they have a great own electronic style. The "piano" has 4 seconds sustain and unfortunately ignores key press duration. "violin" is made from a semi- sonorous multipulse timbre. "organ" is the famous black and sonorous droning multipulse squarewave timbre with 4 seconds sustain that attempts to simulate a metal pipe organ rank. Also "horn" has that sustain. The "banjo" is made from plain squarewave (i.e. unrealistic dull) with 8Hz mandolin ring. "music box" is the typical high pitched plain squarewave musicbox timbre with 4 seconds sustain. "guitar" is a harsh timbre with that sustain. The vibrato button adds a 6Hz vibrato to all sounds (by modulating the clock oscillator).
The percussion are all made from either squarewave or shift register noise with grainy digital envelope and have a wonderful Atari POKEY style. The cowbell (squarewave with digital envelope and zipper noise) sounds like a bottle hit. The snare uses a very rough and impulsive hissing shift- register noise (like a historical videogame's MG shot), the hihat uses a quieter hiss. The base is just a quick fading squarewave. These percussion in spite of their basslessness sound incredible vigorous and are an as outstanding sound discovery as the nowadays so well known and everywhere imitated TR-909 base drum.
A bad habit of this instrument is that the PCB traces under the slide
switch contacts are just solder coated (not gold plated) and though tend
to oxidize. Especially the power switch badly suffers from this and makes
the instrument howl by the increasing resistance.
circuit bending detailsThe synthesizer DIP switches basically do the same like the sound select buttons; important is only to wire a diode in series with each switch to prevent unwanted matrix problems when pressing other buttons. Also the drum pads should be upgraded with each such a diode to prevent mess.
The clock speed is set by an internal 50 kOhm trimmer. My pitch control replaces the trimmer with a 220 kOhm pot. The CPU's clock "output" line (originally the trimmer edge pin?) I have additionally connected through another 22k log pot and a capacitor to GND to achieve a 2 level pitch/ speed control (coarse and fine). From the CPU's clock "input" line (originally the trimmer wiper?) there is a resistor connected through a capacitor to +5V. From the vibrato output pin of the CPU a 2nd resistor connects to that capacitor to modulate the clock speed. I wired a 4.7 MOhm pot in parallel to this resistor to make the vibrato depth controllable. Important is to use separately shielded cables for all lines to the additional pots, because they bear HF signals and make the instrument howl badly when left unshielded.
The rhythm from the CPU is going through a 5.6k and a 10k resistor to the amplifier. I replaced the 5.6k resistor with a 4.7 kLog pot (clockwise input at the CPU, wiper output at the 10k resistor) to control the rhythm/ organ volume balance.
The envelopes of the 2 main voices are controlled each by a 22nF (or µF?) cap against +5V. At each voice I wired [a 1M log pot in series to a 4.7µF electrolytic cap] parallel to the 22nF cap to make the envelope fade slower. Also I added [a 1M log pot in series to a 2.2k resistor] in parallel to the 22nF cap to permit to make the envelope shorter and sound harder. Since it is much more comfortable to control the same parameter for both voices with a single pot, I used 2 stereo potentiometers instead of 4 normal pots in a way that the same function for both voices is controlled by one stereo pot.
With a power supply the instrument hums badly and can easily burn out when PSU voltage is set to high, thus I replaced the 1A diode from the 9V input jack with a 7805 voltage stabilizer which I equipped with each a 1A diode in the input and output line, and [2 diodes in series] in the GND reference line to rise the output voltage to about 6V, which corresponds to the battery pack voltage.
Attention: I have only very incomplete draft schematics of my modification, thus this description might be partly inaccurate or even wrong since it is based on them.
This instrument may be hard to find on eBay because it has usually no model name printed on it, but they don't seem to be rare; I saw yet many specimen sold as toy keyboards there; it was also released as GPX MC-2000B (see here what the direct predecessor Elite MC 2000 looked like) and another was claimed to have the brand name Treton. I was e-mailed that also a variant CX500 exists (only 3 step volume sliders, louder sounds brighter). The normal version has a black, rectangular case, the speaker left next to the keyboard. Above the keyboard are (from left to right) 3 vertical grey sliders, 2 fields of green and some yellow rectangular buttons, then the mike jack and as the most recognizable feature a row of 4 red, slanted, oval and lens- like shaped drumpad buttons, but the button colours may vary. Typically the box is labelled "portable electronic keyboard". The case of this instrument is a close imitation of the Yamaha PSS-30, which looks almost identical beside it is shorter and has no drumpads. A Danish/ Swedish variant with different button colours and no microphone jack is known under the brand name "Music Time". It has instead of the microphone volume a rhythm volume slide switch and also the power switch looks different. In USA the EK-001 was apparently also released as an electronics hobbyist kit with a slightly different case as Stereophonic EK-900 (despite only 1 speaker); its speaker grill had vertical instead of horizontal grooves and it was likely also sold in Germany as assembled version (both with different button colours, seen on eBay). A very different looking variant (round speaker to the right with square drumpads below) was released as Superb Sound EK-210 and another one was likely the Unimax keyboard (white case with 29 midsize keys, semicircular blue speaker to the left, white handle to the right, buttons yellow and knobs red - seen on eBay). Other case variants include the Elenco EK-900 (with blue rectangular drumpads & sliders, speaker to the right) and Music Designer CX-500 (told by e-mail).
Possibly the EK-001 is one of the instruments those were once also released under the Fujitone brand. Above the drum pads stands "custom drummer", which seems to be typical for a series of certain squarewave instruments (made by Medeli?). Also instruments with differently coloured EK-001 case variants (e.g. yellow, red or white) were made, those often contain My Music Center or My Song Maker hardware variants (seen on eBay).
A direct predecessor of the EK-001 was apparently the "Grand Prix KB 893" (see here), which had exactly the same case (besides some buttons and only 3 drumpads) but contained the same hardware like the Pan Toys MC-7. A toy keyboard with similar monophonic sound hardware was the Playskool - Kid Keys PS-635.
The keyboard is very responsive; especially the white keys play almost like a sensor keyboard, which permits special play techniques. The volume switch can not be set lower than medium ambient volume. The company Crown is said to be the original inventor of the ghettoblaster (in 1970th), and in mids of 1980th they released one of the first cheap portable CD players.
This keyboard seems to be very rare; I never saw another one, nor any other Crown or Crowntone instruments yet. However the box of my Intersound - Guitar Star - Rhythm Guitar MT-7112 shows a version labelled Crown MT-7112.
Also this quite big and loud playing midsize tablehooter is based on Hing Hon EK-001 hardware; unlike the latter it has instead of the rhythm volume control a sustain switch.
|Bizarre is that the manufacturer's name has 3 different writings on the case; the logo spells "MeiKe" (abbreviated?) while the control panel writing says "MEIKER SERIESPRODUCTS" (note the 'R') and the "Quality Certificate" sticker at the case bottom even has a writing in a strange font that looks like "Meiskesgs" or "Meirkergr". I could imagine that the word "MEIKER" was genuinely intended to be "MEIKE ®", but the Chinese control panel designer didn't understand what an "®" sign is. Likely the genuine manufacturer is Meisheng (aka Miles), which belongs to Yongmei, the creator of the worst keyboards of the world (see Golden Camel 7A and Miles - Golden Camel-11AB). The name "MeiKe" possibly abbreviates "Meisheng Keyboards". Also my Golden Camel-11AB had a similar "Quality Certificate" sticker underneath, which is black and only says "Miles".|
Like those Golden Camel tablehooters, also the hardware of the MeiKe MK-320B looks like soldered together as piecework in a Chinese concentration camp, since it contains an incredible mess of loose cables. Also the keyboard keys employ instead of a PCB a row of sheet metal contacts with a zillion of hand soldered cables instead of modern silicone rubber contacts. And worst - the "DC:9V" AC adapter jack is also here wired parallel(!) to the battery compartment, thus any attempts to use it with batteries inserted may cause the batteries to EXPLODE (and also the microphone would certainly not survive to be accidentally plugged in here instead of the identical "karaoke" jack next to it).
This instrument was also released as DigiTone Expert (seen on eBay).
A likely direct predecessor of this hardware was the monophonic Yongmei MS-210B (same sound generator but different percussion). A successor of this thing was possibly the Miles 3738. Another great multipulse squarewave keyboard with fast (C64 style) arpeggiator sounds and synth features is the Yamaha PSS-100. Another instrument with great POKEY rhythm is the Creatoy keyboard.
This extremely rare keyboard is technically almost identical with the MeiKe MK-320B, but it includes an additional melody chip for 8 additional demos. The demos are primitive monophonic tooting squarewave monotos, but these very short melody loops can be abused as tekkno accompaniment. The extremely flimsy plastic case is the same like with Yongmei MS-210B.
warning: Never send a keyboard with this case through mail without multiple centimeters(!) of padding (styrofoam, firmly crushed paper, fanfolded cardboard or similar), because the plastic is brittle like glass and will unavoidably shatter into a zillion of pieces as soon they toss it around in the mail. (Older Yongmei keyboards original packaging contains no end padding at all and thus is absolutely unsuited(!) for mail shipping.)
A year ago I had ordered my first MS-110A specimen, which arrived slightly shattered at one side. When I reported that damage in a Deutsche Post post office, the spirt- nosed post office clerk smeared a few words across the damage report form (instead of filling out the entries), intentionally smashed the remains of the wrapped keyboard with a huge 20kg parcel on a trolley and sent it back to the sender despite I explicitly requested to sent it back to me after damage analysis. I never saw that keyboard again nor I got any money back. Later I fortunately found another specimen of this extremely rare keyboard on eBay; first the vendor indeed followed my instructions to pad the parcel ends very well etc. etc., thus it indeed stayed in one piece, but when I took it out, it turned out that despite outer parcel he had for no reason at all ruined the original box with brown adhesive tape - arrg! I managed to remove it without too much damage, but afterward he even gave me a negative rating because I did not immediately bike through the mountains down to the bank to transfer the remaining 90ct of postage. Why the #@*!% are sellers of rare Yongmei keyboards always such assholes?!?
The box has the same old style like with the first generation transistor tooter Yongmeis (see Golden Camel-7A), and like with these the box feature list is full of lies:
|In reality it has neither a "Stereo Effect" (the amp is mono) nor "Encircled Sound" nor " "Single Finger/ Fingered Chords" and only 8 instead of 10 "voices"/ preset sounds. Instead of "12 Demonstration Songs" there are only 8+1=9 demos. But instead of "37 Standard Accordion Keys" it has even 44 keys (but only 37 are real).||. o O|
|Made in Mei Sheng electronics factory Jiexi Guangdong China.||a blank sticker...|
|The jacks writing is in Chinese.|
|This thingy is the melody IC.|
The preset sound and rhythm names contain plenty of Engrish misspellings. The vibrato is named 'trill'.
|When the melody chip is enabled (switch 2 is on), the leftmost 7 keys select the demos. Any white one selects the next melody (and keeps it repeating when held), while any black key stops the melody and selects melody 1 again by resetting the melody chip. (Warning: The power LED dims a bit by black key presses, thus it may overheat the chip when pressed too long by a missing resistor thanks to the infamous Yongmei hardware bugs.) But genuinely the melody chip has only 2 button inputs anyway; the leftmost 4 white keys and switch 4 are simply wired parallel as melody select, while the 3 black ones are wired parallel as melody reset, thus they all do the same.|
The 8 melody chip demos are:
A direct successor of this instrument was the Yongmei
|removal of these screws voids warranty...|