PS-6100 (1984)
The birth of a new concept
Release Date: 1984
Introduction
In early 80s, portable digital keyboards with built-in speakers, preset (non-editable) sounds and automatic rhythms or accompaniments were relatively new, but not uncommon. In those years, Yamaha released their first line of home electronic portable keyboards, the PS series, which was the direct antecessor of the ultra-famous and successful PSR line. But mostly, if not all, of those keyboards were conceived as low-end, even toy-like entertainment devices unsuitable for any “serious” or professional use. Professional electronic music equipment was eagerly expensive those days, and required an investment of several thousands of dollars, so this was not the target of entertainment keyboards for use at home, or indeed, anywhere.
But in that context, Yamaha, who already had their line of professional synthesizers and had a big success with the new (back then) DX series, decided that it was a good idea to release an auto-accompaniment keyboard with the same technology of their professional synthesizer line. So they designed and released in 1984, shortly after the DX7 and even before other models such as the DX21, DX27 and DX100, a high end home keyboard, the PS-6100. The original price was almost the same as the DX7 (220,000 yen, whereas the DX7 was 248,000 Yen), so this gives an idea of the level of the technology involved in it. So the intention was clearly to offer more than just a “mere” home keyboard.
Looks and design
The design and form factor also reveals that the PS-6100 was a high-end product. The control panel folds, so you have to open it when in use, making it significantly bigger, and when not in use, it can be fold back, revealing a clean and stylish design, at the same time that it’s better protected against dust and possible accidents such as hits from falling objects and the like. It has also an ingenious system for the music rest, as it’s hidden inside the top panel and you can unfold it when needed, and then fold it back again when you’re done. Also, as it’s fixed to the panel, you cannot get it lost, unless you break it 😉
The keyboard is quite long due to the speakers, placed at both sides of the keys, but when folded, it's quite slim, both in depth and in height. While not being a light keyboard, it’s not a very heavy one either. It’s built mostly in plastic instead of metal, but it feels solid and sturdy, and the sense of build quality is certainly there.
The panel does not have any led or LCD screens, but you have individual buttons for nearly every function and their descriptions are self-explanatory, so a screen isn’t really needed. It could have been nice to have at least a segment led screen for the tempo, though.
The connections also reveal that this is quite a “serious” keyboard. One thing I really like is that it has an internal PSU, and that the power cable is detachable (it has a two-pin IEC connector for the power). Many “professional” keyboards of that time (including the DX7) and even from several years later had an attached power cable, much more uncomfortable and prone to suffering accidents. On the rear you’ve also got midi in and out (but not thru) terminals (which is remarkable given that it was a very recent standard back then), stereo line outputs, a line input, a foot switch input (not only for sustain), an expression pedal input, tape connectors (for saving and loading data), and a knob for adjusting the pitch. On the front side there’s also a headphones’ plug.
The keyboard feeling is good, and it has aftertouch (no other Yamaha’s arranger would have aftertouch until several years later), but oddly enough, it’s not velocity sensitive. In fact, this is the only model I know that has aftertouch without being velocity sensitive. Even more strangely, the aftertouch only works with “solo” voices (more on this later), which are monophonic. This is a severe limitation for the expressiveness of the keyboard, and it’s a pity. Also, for a keyboard of this level and price, there should have been pitch bend and/or modulation wheels, but they are absent.
The slim and sophisticated looks of the PS-6100 become more evident when the lid is closed
The hardware
If we take a look at the hardware specs of the PS-6100, we soon realize that they were quite impressive for that time. The synthesis engine is based on the YM2164, also known as “OPP”. It’s not the same chip as the DX7’s YM2128 (OPS), and does not offer its 6-operator, 32-algorythm FM synthesis capabilities, but it’s not bad at all. In fact, the OPP was used in several “pro” models such as the DX-27, the DX-21, the DX-100 or the FB-01, among others. The OPP provides “only” 4-operator, 8-algorythm FM synthesis, and it has a polyphony of 8 voices instead of 16, but on the other hand it’s also 8-part multitimbral, as opposed to the DX7, which was monotimbral. The OPP, just like the OPS, is based only in sine waveforms, but still can provide a quite ample variety of sound timbres.
But the interesting point is that the PS-6100 contains not one, but two OPP chips, for providing a total of 16 voices of polyphony. Moreover, the drums and percussion sounds are not generated by FM synthesis, but they are PCM, thanks to the YM2154 (RYP4) chip, which was used in some of the RX line of Yamaha’s drum machines, such as the RX-11 and the RX-15. So, in sum, it could be said that, from a hardware point of view, the PS-6100 is like having two 4-Op DX synthesizers and a RX drum machine in a single package. Not bad at all for a “simple” home keyboard!
Sadly, and despite this great potential, it seems that Yamaha did everything they could to avoid any possible “serious” or “professional” use of this keyboard. I suspect that they wanted not to compete against their own line of professional models and they wanted to stress a clear separation line between “hobbyist” and “pro” keyboards, but IMHO they sacrificed too much, especially considering the high price tag of the PS-6100, which was much more expensive than a DX-27, for instance. Some of those shortcomings or limitations have been already pointed out, such as not having a velocity sensitive keyboard, the absurd limitations of the aftertouch, or not implementing pitch and modulation wheels, but there are others.
The sound
The PS-6100 has three different melodic parts, which can be individually turned on and off in every possible combination and have their own independent volume slider: “orchestra upper”, “orchestra lower”, and “solo”. The “orchestra upper” and “solo” parts can be played throughout the whole keyboard range, whereas the “orchestra lower”, as its name suggests, are for the lower part of the keyboard, with three selectable (but fixed) split points. So, when all three parts are active, the keyboard is in both “spilt” and “dual” mode: one sound for the lower part and two for the upper part. Each part has its own sound palette, so you cannot select an “upper” or a “solo” sound for the lower part, or vice versa. There are a total of 18 preset sounds for the “upper part”, another 18 for the “solo” part, and only 6 for the “lower”. The “solo” part is the only one that can respond to aftertouch (you can switch it on or off), but this part is monophonic, no matter whether the other parts are active or not. Indeed, the “upper” and “lower” parts not only not respond neither to velocity nor aftertouch, but moreover, this keyboard does not even respond to velocity via midi in (!), and this is a severe limitation for expressiveness. On the other hand, though, there is an independent “sustain” switch for each part (two of them for the “upper” part, in fact), and “ensemble” and “chorus” effects for the “upper” part, which seem to be analog and sound pretty warm and good. This is the only available effect, as there is no DSP to provide reverb, delay or whatever (they weren’t common until late 80s/early 90s, anyway). There is nevertheless a “melody plus” feature which adds two or three harmonization notes to the melody when playing accompaniments.
The preset sounds are not editable at all, nor new sounds can be added. Most of them are (try to be) emulations of “real” instruments, rather than synthetic or experimental sounds. This may be understandable in a keyboard focused in entertainment rather than in music production (it’s not a synthesizer and it was not marketed as one), but the great problem here is that FM synthesis was still rather new then (the DX7 was released just a year earlier), and Yamaha just didn’t acquired the necessary expertise to design good FM sounds yet, so in general terms the presets sound very artificial and dull, and do not show the real potential of the 4-Op FM sound synthesis. Even considering that FM is not precisely the best technology to obtain emulations of “real” instruments, if you compare the presets of a Yamaha V50 (a 4-Op FM synthesizer released in 1989) to the PS-6100, the differences are abysmal. For example, the acoustic piano preset sounds practically indistinguishable to the one of the PSR-12 (a low-end 2-Op FM keyboard released in 1987). The most remarkable exception is the “jazz organ” preset, which sounds quite good, especially with the chorus/ensemble effect added (this is understandable as the 4 operators are used as carriers, in AM synthesis).
Regarding percussion, the PS-6100 provides a total of 21 different PCM sounds (including drums and latin percussion), inherited from Yamaha’s RX line of drum machines. Sadly, you cannot edit pitch, panorama, or even relative volume other than an “accent” function, so the resulting sound is quite plain and mechanic. Also, given that in that time ROM memory was very expensive, the drum samples are very short and there's not even a cymbal crash sound, probably because being longer, it was too memory hungry. As with the melodic parts, there is an independent volume slider for drums.
Some sound examples:
Rhythms and accompaniments
The PS-6100 has 32 different preset accompaniment “styles”, which, as usual, include a rhythm pattern, a bass line and rhythmic chords and/or arpeggios which respond to the chords played in the lower part of the keyboard. Sadly enough, it’s not possible to change the timbres of the accompaniment parts, but at least there are independent volume controls for drums, bass and chords. Each preset style has a “variation” version, and that’s why Yamaha advertised a total of 64 rhythm patterns. In modern arranger keyboards, the different variations of an accompaniment style usually take the same musical concept and increase complexity, adding more elements and details, while keeping the same feeling. The PS-6100 is quite different, as in many cases the two “variations” are more like different versions of the same music style. On the one hand, this can be good in the sense that there are more variety of styles, but on the other hand, it makes it more difficult or awkward to combine the two variations on the same performance, as the differences are very noticeable, and if you opt for keeping the same variation during all the song, the performance becomes plainer and more boring. A feature which adds more flexibility, though, is that you can select either if the accompaniment remains or if it stops when you are not playing the chords with your left hand (a kind of “synchro break” feature). There is also a dedicated break button for the same purpose.
As a curiosity, there are two “handclap” buttons, which, as the name suggest, add rhythmic clap sounds to the drums. The clap patterns are different for each style, which is nice. There is no “intro” nor “ending” for the styles, which is a shame, although the keyboard provides four different fill-in patterns for each style. Oddly enough, there is only one fill-in button. You can change the pattern by pressing the fill-in 1, 2 o 3 button (two presses on the same button deselects it). In case that none of them are selected, it applies some kind of "fill-in 0" pattern by default. So, if you want to change the fill-in pattern during the performance, you must press two buttons (first, the fill-in 1, 2 or 3 to change the pattern -or to deselect it-, and then, the fill-in button), instead of only one, as usual.
You can program up to two different custom rhythm patterns, but sadly there is not the possibility of programming the rest of the accompaniment tracks, so you’re stuck with the style you select prior to program the drums. It’s all pretty limited, but anyway better than most, if not all, all the other keyboards of that time.
Some accompaniment examples:
The recorder (“music programmer”)
One of the most “pro” features of the PS-6100 was the multi-track recorder or sequencer, labelled as the “music programmer”. In fact, this denomination promises more that it really is. There are 4 different tracks, and their type is fixed (you cannot record four different melodic lines, for instance). One of the tracks is for recording the chord progressions of the accompaniment. There is the possibility, though, to exchange the automatic bass line for your own bass performance, using another track (labelled “manual bass”). The other two tracks are for “solo” and “orchestra”, respectively. The memory is quite limited (200 chords and 800 notes for the melodic tracks). Nevertheless, the recordings are stored in non-volatile memory (they are not lost when power is turned off), and they can be saved into tape (as also the custom drum patterns).
Amplification, connections and MIDI
Although a high-grade, high-end model, the PS-6100 was designed as a home keyboard, so it has its own built-in amplification and speakers. Despite being marketed as a high-quality amplification system (2 x 5W stereo), the fact is that the onboard sound is undetailed, with virtually non-existent low frequencies, undetailed highs and gritty mids. Indeed, Yamaha didn’t provide a decent amplification and speaker system in their arrangers at least until the PSR-5700 (released in 1992). The sound is much better through the RCA line outs, although there is a quite high noise floor level. Obviously, this wasn’t intended to be used professionally in a recording studio.
Despite the PS-6100 provides MIDI ports (a recent technology back then), it’s quite shocking that the manual practically doesn’t pay attention to the PS-6100’s MIDI functions and capabilities. There is not even a midi implementation chart. I was lucky enough to once read the service manual (it seems that it’s very difficult to obtain now), and there were more details there about the midi implementation. But as long as service manuals are usually not available to the final user, a standard owner of a PS-6100 doesn’t really know what the keyboard is capable of. The most relevant point here, IMHO, is that, like many other models of that era, the midi mode is “OMNI ON”, instead of “OMNI OFF”. The “omni on” mode means that the keyboard receives the data simultaneously through all 16 midi channels, so it’s not possible to get a multitimbral setup in which for instance midi channel 1 is for the piano, channel 2 for the bass, and so on. In other words, it’s not possible to use the PS-6100 as a multitimbral midi sound source in a DAW. Instead, when played via midi is like using the keyboard remotely; no matter the midi channel, it will behave as if playing the keyboard itself.
Despite this, it seems that the PS-6100 has a "hidden" or special MIDI mode explained in the Service Manual, which is called "exclusive mode", and which would allow for a multitimbral use across different MIDI channels, although with several limitations (channels are fixed, as well as the polyphony of each one and the avaliable sounds for each part). As I don't have the Service Manual, I cannot provide the details, although I remember that the manual explained this in some level of detail. The only information I've been able to get is from a certain webpage, and which I paste here:
The keyboard powers on in what Yamaha calls "normal mode". That only includes note on/off data, upper-voice selection, upper-voice volume, upper-voice sustain, and timing data — all on MIDI channel 1.
There is also an "exclusive mode" you can switch to that will enable additional data for the lower and solo voices, aftertouch, chord/bass/rhythm sections, and all the buttons on the panel. These additional messages are spread out across MIDI channels 2-16.
To enter exclusive mode, turn off the Orchestra Upper section, then hold down the Solo button and press the Piano button in the Upper section. If you are monitoring the keyboard's MIDI output, you can quickly tell it worked by watching for messages generated when you move one of the volume sliders (like the Solo volume) that normally don't send MIDI data.
If I ever have the oportunity to get the Service Manual again, I promise to investigate this.
Besides MIDI in/out and RCA line outs, the PS-6100 has a mono line imput, a jack input pedal (not only for sustain), an expression pedal input, (which in that time came with a RCA connector instead of a jack), a headpones output in the front, and tape in/out connectors for loading and saving data, such as custom accompaniments and multitrack recordings.
The different connections and ports of the PS-6100
Verdict
Although it has been a long trip, the PS-6100 could probably be considered as the oldest ancestor of current high-end arranger workstations such as the Genos. The differences in terms of specs and sound quality are certainly huge, but the core concept of an arranger keyboard with the most advanced sound technology, the capacity of creating custom accompaniments, muti-track recording, extensive connectivity, etc., remains the same in essence. The key difference, as I see it, is that the idea of using an auto-accompaniment keyboard professionally was still far, and Yamaha themselves did what was at their hand in order to prevent that possibility introducing several limitations that spoiled the great potential of a device equipped with two DX synthesizers and a RX drum machine. In some sense, the PS-6100 was like having a Ferrari but being only able to use the first gear.
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