Yamaha PSS-30, PSS-130 (small squarewave keyboard with unusual percussion)

Yamaha PSS-30

This small Yamaha PortaSound keyboard from 1987 (embossed case date) was apparently the model for the case design of the great Hing Hon EK-001. It has 2 voice polyphonic squarewave sounds, a few interesting electronic percussion and a monophonic sequencer that can be played to.
(photo from eBay, showing my specimen)

main features:



The main volume of this instrument was initially so loud that the sound distorted, and it could not be well adjusted with the too coarse 4 step volume control (possibly because there was an uncommon 6 Ohm speaker instead of an 8 Ohm one built-in). I added a 10 Ohm resistor in series to the speaker to reduce the volume. Fortunately the volume control at least steals no resolution bits from the sound envelope like the Yamaha PSS-20 did.

Despite the control panel layout of this instrument resembles very much the more complex Yamaha PSS-80, I found no keyboard matrix eastereggs those could hint the existence of its features in the PSS-30, and also the CPU is different. In a Yamaha chronology was claimed that the PSS-30 came out already in 1982 while the PSS-80 was 1989, but inside the case of my PSS-30 is a punched mark with "87" and {6, 7, 8}, thus I conclude that mine was rather made between 1987-06 and 1987-08. The case style also doesn't really look like from 1982, thus I think that was rather an error.

note: Several circuit benders asked me strange things because they apparently confuse this keyboard with something else. Thus to say it again here - this keyboard has absolutely nothing to do with FM synthesis, nor you can get any remotely interesting new sounds out of it by circuit bending. There are no eastereggs, and it uses one of the most stubbornly pre- programmed chips I ever found; all you can get by shitshots are boring things like playing demos with wrong instrumentation, make the instrument start at different rhythm tempo and so on. You may distort the analogue parts or replace the clock oscillator, but that's it.

The sounds are digital squarewave with audible zipper noise (similar like the Letron MC-3). The "electric guitar" is rather a thin organ with vibrato. Also the "violin" has vibrato. The "xylophone" is a short blip. The "banjo" includes a ringing mandolin effect. All tones are a little rough/ gently distorted and remind to friendly C64 SID sounds. Like with many old OBS keyboards you can hold a key down and bounce around among sound select buttons to rhythmically switch the timbre.

The drums are squarewave blips of different pitch. The cymbal/ hihat consist of an unusual digital waveform that has a metallic timbre with a lot of dull noise; its timbre resembles compressed air or gas flowing through a valve within narrow metal tubes. (This may be an extremely low- res waveform sample.) A similar cymbal has also my Yamaha MK-100. Although the keyboard is only 2 note polyphonic, the sequencer can be used to playback a 3rd monophonic voice while playing to it. (Rhythm does not reduce polyphony, but sequencer playback always starts the rhythm it was recorded with. The sequencer can not be used without rhythm, and always plays with the sound that was selected first during recording.)  The monophonic demo tune (Yankee Doodle) cycles through all sounds and can be also accompanied 2 voice polyphonic. Like with the sequencer, the user selected sound only affects keyboard play but not the demo tune.

Yamaha PSS-130

A midsize keyboard version of the Yamaha PSS-30 with foil buttons was released in 1986 as Yamaha PSS-120 and re- released in 1987 as PSS-130 (with different button colours).

An idiot at eBay sold this thing without photo, claiming in few words it would be a (never heard) "Yamaha Pss133" and "like new". I asked by e-mail if that was a typo, but he claimed the type was correct, thus I dared to bid for it as the only bidder. I won and he wrote he would only answer by phone. First only a granny answered, who knew not a brown smelly sausage what eBay is. When I finally reached her son(?), he told me that he had yet no own PC and still claimed the keyboard would be a PSS-133. But when it finally arrived I disappointedly found in the parcel the at that time very dirt stained PSS-130 (not just wrong model, but not even remotely "like new"), thus I gave him a negative eBay rating with explanation that he delivered the wrong model PSS-130 and very dirty. The sucker returned me a negative revenge rating, claiming that I lie and that it would be indeed a (likely never existing) "Yamaha PSS-133". Afterward he even had the impudence to request additional 2€ postage from me because he had accidentally written the wrong postage amount in his announce. But I strictly refused to pay these 2€, wrote him an annoyed detailed e-mail and reported the incident to eBay. =>When anyone is to stupid to describe his wares correctly on eBay, then he should piss off there and sell it on a flea market instead!

SER.NO. 1438029

A similar sounding but more advanced squarewave instrument was released as Yamaha PSS-80, which contains even a primitive synthesizer (4 buttons select timbre brightness and envelope duration).

 removal of these screws voids warranty...    
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