Yamaha PSS-7

Yamaha PSS-7 (pretty wavetable toy keyboard with unusual granular sounds)

This small "Young Yamaha" toy PortaSound from 1997 is possibly not the best sounding, but at least the prettiest of all Yamaha keyboards. It makes a lot of great granular tekkno noises including a quite unique sounding lo-fi keyboard drum kit mode. All sounds are made from wavetable synthesis based on low resolution samples.

main features:

32 mini keys (black keys are flimsy and may crack off easily when accidentally bent upward)
small built-in speaker (sounds thin)
main voice polyphony 2 notes (and 4 for rhythm/ accompaniment)
100 preset sounds divided into 3 groups with 1*5 and 2*10 sounds and each 4 variants per sound selected by a variation button:

"i1" = combo {piano, e guitar, saxophone, e bass, percussion}
"i2" = keyboard {e piano, harpsichord, organ, clavi, accordion}, strings {f guitar, violin, strings, harp, banjo}
"i3" = wind {trumpet, flute, harmonica, vibraphone, marimba}, effects {pig, cat, telephone, tv game, chorus}

30 preset rhythms ("bands", containing accompaniment) selected by 3 group buttons:

"b1" = cool {Top 10, Video Pop, House, Reggae, Jazz}, hot {Rock, Funk, Bossa Nova, Salsa, Surf}
"b2" = classics {Music Box, Gymnopedies, Für Elise, Siciliana, Polovtsian}, favorites {Musical, Merry- Go- Round, Pop Ballad, Lullaby, Waltz}
"b3" = showtime {Comic Dancer, Space Fantasy, Entertainer, Mambo, Lovely Alien}, funtime {Horror, Spy, Fanfare, Safari, Carnival}

tempo +/- buttons (16 steps) + "tap" button for intuitively tempo entry
volume +/- buttons (16 steps, reduce bit resolution badly)
"AWM" wavetable sound generator which uses many tricks with low- res samples and employs partly very complex algorithmic volume and pitch envelopes. E.g. the "cat" sound sounds really robotic because it is made of a sequence of many short waveform sample fragments. The sounds contain a small dose of aliasing noise.
CPU "Yamaha YMW-716C-D"
10 demo songs (nicely instrumented, but unfortunately most are quite short)
jacks for 9V AC adapter (polarity protected) & headphone/ line out jack

notes:

All button presses either play the selected sound or a low knocking bongo noise at maximum volume (not very loud). When batteries run empty, the instrument resets/ stutters as soon buttons are pressed, and due to the instrument starts always with a fanfare at the loudest setting and plays that loud bongo by pressing the volume buttons, this makes it sometimes impossible to turn it quieter before it freaks out. I tried to add electrolytic capacitors etc. to fix this but had no success.

Although it is nothing really great, this instrument contains many strange lo-fi sounds and preset sound patterns those can be interesting for tekkno. E.g. the very robotic animal voices (cat, dog, pig, cow) sound wonderfully synthetic, and also the noisy (Fairlight- style) low- res sample choir (called "chorus") sounds nice. There is a drum kit mode with very synthetic tekkno cymbals (made from a short looped semi- metallic waveform with decay envelope) and a strange snare that resembles a typewriter. When 2 keys are pressed with short delay, the drums make a great phasing effect. The ringing mandolin ("f guitar" 2) makes every 0.5s a rhythmical short pause. Some sound variations include an echo effect and there are many strange monotos (melody loops) those can be melodically played on the keys and some of them are well usable for tekkno. E.g. "tv game" 3 is a gritty falling pitch glissando siren, and there are even 3 drum patterns those can be rhythmically played on the keys (same note pitch). But unlike the echo on the predecessor Yamaha PSS-6 here the main voice preset sounds ignore the tempo setting. The timbres are a little rough; especially the plain squarewave tone "tv game" reveals in high notes noticeable aliasing noise.

(The full sound set list can be found in the manual of this instrument, downloadable on the Yamaha Manual Library site.)

The internal fixed- key accompaniments otherwise doodle so stubborn that besides "safari" they are of almost no use for playing any real music on it. I really miss a sort-of long "space bar" key below the entire keyboard to switch between main voice and chord mode during play, or at least some user preset functions, but however, the thing is just a toy and was likely simply invented to let kids improvise to a given background monoto for learning to play/ tinkle together with a virtual band and get the feeling for triggering preset patterns to a preset accompaniment rather than playing own music on it. The access to the sounds is also everything but OBS; group buttons need to be pressed multiple times while the actual sound is played by each of these button presses - this makes sound switching during live music performance almost impossible. Despite all this the PSS-7 is a quite inspiring thing with many unusual sounds. Interesting is that the squarewave preset sound is called "tv game" here, and there is also a style "video pop" that reminds to a typical jingling NES or GameBoy background music; this proves how much the unforgettable sound of historical videogames has already found its way into the mainstream.

The 10 demo melodies are:

Mickey Mouse March
Little Brown Jug
Mission Impossible
Chopsticks
Jingle Bells
Pop Goes the Weasel
Gallant Pig
Awarding an Honor
Kissing Santa Claus
Over the Rainbow [very bluesy]

Most demos are extremely short, and there is not much difference between these and the "bands" (accompaniments), of those many also constitute monotos (repeating short melody loops) except that the demos mute their main voice when the player plays to them on the keyboard.

A 4 note polyphonic midsize version of the PSS-7 was released as Yamaha PSS-14 and PSS-15; beside it has 2 different demos, it behaves identical. Due to the PSS-7 has a diodeless keyboard matrix (with narrow and difficult to modify carbon trace contacts on the very small main PCB), its CPU would be anyway incapable to sense more than 2 simultaneous key presses without problems. Due to there are 18 places unoccupied in the keyboard matrix, I initially thought that the PSS-14 would have exactly the same CPU with a diode equipped matrix and an additional diode somewhere to tell the CPU to activate the 4 note polyphonic mode. But I didn't found out how to activate this mode and there also seem to be no other keyboard matrix eastereggs. Later someone told me that his PSS-14 has a slightly differently labelled CPU "YMW 716D-D"; I am not sure if it is just a different revision number or if this causes the polyphony difference. Later I bought my own PSS-14, which turned out to have yet another CPU and also 2 different demos.

The direct predecessor of the PSS-7 was the Yamaha PSS-6. Strange is that despite it is older, it had a way higher sample quality and 15 very long and complex orchestrated demo melodies (but it sounds also more establishment and has no great tekkno noises); likely the resolution was reduced because Yamaha eliminated the separate ROM IC (found in PSS-6) to cut down the costs. Another nice tekkno mini- keyboard with wavetable sounds is the Casio SA-5 (and its better midsize variant SA-35).

*removal of these screws voids warranty...*

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