SANKEIEntertainer

TCH-8800

 compact stereo set with warm analogue organ & rhythm

The odd Japanese 1970th compact stereo set contains a nicely warm sounding full polyphonic analogue organ with analogue rhythm. It has no accompaniment, but the 5 OBS rhythm buttons are combinable and there are many separate volume controls like on a mixing console.

The main voice is an almost envelopeless plain squarewave organ tone; instead of preset sounds there are only 2 octave settings, but it has a lovely ancient warm timbre and square vibrato. The 5 OBS rhythm buttons are combinable to get 31 rhythms in total, those have a typical analogue home organ appeal and can be switched at any time (nice for tekkno). All functions are selected through locking OBS switches, there are bass & treble controls and plenty of individual volume knobs. The tip of the rod antenna contains a small microphone for singing or recording on the built-in cassette recorder. The radio and cassette deck are nothing special and pretty standard for their era; at least you can adjust the record level, and like with a mixing console you can mix cassette, microphone, rhythm and organ together in various combinations. Although the organ main voice (not rhythm) turns off the radio, and as well radio as cassette have no own volume controls, all other combination work and you can also mute the channels individually with their buttons. The cheap plastic speaker boxes have too little bass for their size.
 
The instrument was made in Japan with the strange brand name Sankei, which I never saw before. But because such names are usually translations from Asian characters, they may later have renamed itself into Sankai, which is nowadays a Chinese company related to Yongmei and released cheap plastic tablehooters like the Sankai 01504H and 01870K. However this old Sankei Entertainer is still fairly heavy and not particularly waggly.

main features:

eastereggs:

notes:

This strange compact stereo set was likely built in mid or end of 1970th, since the full polyphonic keyboard hardware has no keyboard matrix and contains for each key still a synched oscillator with plenty of discrete components - a concept that was abandoned in later full polyphonic instruments (see e.g. Ramasio 892). Also the flat case shape is typical for 1970th; my father owns a black Schneider stereo set in the same shape (with record player and no keyboard) made in 1976. When I bought this thing on eBay, it was horribly dirty, like when it had spent its last 20 years in a hen stable. There were centimeters of caked dust and animal hairs inside, a loose metal part from the cassette recorder rumbled around and the PCB traces under the keys were full of smeary goo and partly corroded through because either the thing was operated after it had badly rained on it, or someone had spilled a corrosive drink on the keys in his cellar bar. But after thorough cleaning, patching rotten copper traces with soldered wires and replacing cassette deck belts and a missing screw, I finally got it to work. Only the ALC switch of the tuner does almost nothing beside slightly moving the needle of the tuning meter, and the potentiometers are still noisy.

Unique is that the antenna rod tip is a small microphone, however this has the side effect that unlike standard telescope antennas this one is not extendable, because the cable inside would likely make such a mechanism much more complicated to prevent twisting and properly wind up the cable. Another unique feature is the mains plug, which consists of a small US plug that is relatively firmly inserted into a small adapter for European sockets. The lightweight plastic speaker boxes are a cheap construction with too little bass for their size and a tubby midrange resonance that is particularly audible during keyboard play. (I own similarly lightweight RFT plastic speaker boxes with only 4W sine/ 6W music power rating (from a broken Europhon record player), those full range speakers have almost high-end quality and sound great when placed on the floor and running through a small tube amplifier.) Generally I would not recommend to turn this thing too loud, since neither these flimsy speakers look halfway robust, nor were average 1970th compact stereo power amplifiers particularly reliable. (I have repaired a dozen of them after teenagers or my father toasted the amp at full volume.) As usual with ancient analogue organs, all controls employ locking OBS switches and respond immediately, which permits plenty of live play tricks. Near the right front rim of the case bottom there is a fixture for an attachable knee lever (which my specimen is missing) to turn the organ voice louder and brighter. Bizarre is that at the case bottom there is a square black cover, which inner side has closed embossed marks for speaker grill holes. Apparently a predecessor with a single internal speaker or subwoofer at the case bottom (like in 1970th Bontempi keyboards or Casio MT-640) was planned or made.
The organ main voice is a simple plain squarewave toot, which has almost no envelope and resembles a wooden pipe organ rank or clarinet. But it sounds better than many other plain squarewave organs, because it apparently has a fixed capacitor filter per key that adds a tiny bit of sustain, and may also mix a small fraction of other octaves into the sound. When the main voice is enabled (it can be switched of, keeping only the rhythm running), you always hear a dose of the characteristic polyphony hum (like pressing down all keys simultaneously). Generally it sounds very archaic, sweet and warm, comparable with an undistorted plain Hammond organ timbre. Because the keys are filtered individually, you don't get the problem that high notes are muffled way too dull (which happened in various preset sounds of early Casio keyboards). The octave button is wider than all other buttons and behaves odd; so long it is up, you get the higher octave; when you push it down at the left end of the button, it will lock and the organ sounds an octave lower. However when you instead push it in at the right end, it will lock a little lower and make the sound additionally duller and quieter. I am not sure if this is a mechanical bug of my specimen or intended as a timbre variation. As a sound effect you can also push it in at the left end (sounds bright) and slightly trill on the right end to rhythmically toggle between bright and dull with a weak pop noise (pushing harder will make it lock at dull). The vibrato button adds a square 7Hz vibrato, which sounds nicely cheesy (speed and depth can be likely adjusted with trimmers inside).

There is neither an accompaniment nor automatic chord mode of any kind. The rhythms correspond to a typical analogue 1970th drum machine or home organ. Despite there are only 5 OBS preset rhythm buttons, they lock individually and you can press multiple of them to switch at any time between 31 rhythm variants without restarting the pattern, which is nice for tekkno. The rhythm volume control not only reduces rhythm volume, but also turns the rhythm duller. The "rhythm" button as well enables the rhythm track (with a pop noise) in the mixer, as restarts the rhythm pattern from beginning, which permits various live play tricks. The tempo can be set quite fast, but not extremely slow (which can be likely modified at the potentiometer).
 

hardware details

The music keyboard of the Sankei Entertainer TCH-8800 is based on typical 1970th full polyphonic home organ technology using Sanyo main ICs. These are the top octave generator LM8071, 5 frequency dividers LM3216 and the rhythm generator LM8972. Everything uses plenty of discrete components for filtering and analogue percussion.
yuckety-yuck... keys got stuck
sneeze - cough cough!

corroded key contacts		 main voice hardware vibrato PCB
On the keyboard PCB is a trimmer to tune the main voice; a small PCB connected to it contains the vibrato circuits with 2 additional adjustment trimmers. The frequency dividers LM3216 may output some additional lower octave notes (not tested).
The knee lever potentiometer can act as a volume pedal. cassette drive motor rhythm PCB

The Sankei Entertainer TCH-8800 seems to be very rare. However in 1970th various fullsize home organs with cassette recorder were made, and it also can be regarded as ancestor of the famous keyboard boombox Casio KX-101 (which uses its cassette deck also for data storage of the its sequencer).
 

 removal of these screws voids warranty...    
WarrantyVoid
back to tablehooters collection
  
 
back