Roland RD-300S
Roland's second-generation S/A digital piano — the 88-key stage piano that put weighted SK-6 action and physically-modeled piano tone in a working player's hands.
Overview
The RD-300S is an 88-key digital stage piano built around Roland's S/A Synthesis Technology, the Sound Synthesis Chip that powered the company's entire digital piano line. What makes this one interesting is its place in the sequence: it is the successor to the original RD-300, and the headline change was the keyboard itself — Roland swapped in the SK-6 dynamic keyboard, which the company described at the time as providing a more piano-like feel than the earlier action. That distinction mattered to players, because the original RD-300's lighter action had drawn criticism for offering somewhat less subtlety of control than a heavier, more piano-like keybed.
The sound engine is the S/A chip, and Roland's own advertising framed it ambitiously — as the most faithful digital re-creation of the acoustic keyboard experience, with grand piano voices that ring with clarity and depth across the range. Mix (February 1988, p.37) ran the company's S/A Synthesis copy, positioning the RD-300S alongside the RD-1000 and RD-250S as the family of instruments built on that circuit. Whether you take the marketing at face value or not, the point of the engine was responsiveness to touch: strike a note hard and you get the attack of the hammer, play softer and the tone rounds out, hold the damper and the notes sustain and decay naturally. Under the hood, S/A Synthesis analyzes the whole event rather than replaying samples — Roland positioned it as an alternative to sampled pianos, urging players to compare the S/A instruments to any sampled piano, even those costing three times as much.
The instrument is a single-sound-at-a-time machine internally. Electronic Musician noted that while you can split the keyboard and send the upper and lower sections on separate MIDI channels — or send the whole keyboard out on two channels at once — you can only play one internal sound at a time. That's a real limitation for a stage piano, and it's worth being honest about: this is not a multitimbral performance keyboard. It's a piano first, and the MIDI implementation is there to drive external gear, not to layer internal voices.
The performance controls are sparse by modern standards, and this is where the RD-300S shows its age. There are no pitch-bend and mod wheels, and no aftertouch. The only per-performance controls are two External Volume sliders that send MIDI volume data for the upper and lower sections. Program changes, split points, and transpose functions are all handled through button-pressing and key-pressing routines — Electronic Musician called the process cumbersome, and that's a fair assessment. The saving grace is that the parameters are silkscreened on the front panel, and the Soft/Remote footswitch can be assigned to serve as a soft pedal, sostenuto pedal, or remote footswitch for transpose, split, program change, MIDI channel, tremolo, and chorus — though only one function at a time. You can also configure the instrument to send program change messages 1 through 8 when selecting sounds from the front panel.
The MIDI velocity curve, according to Electronic Musician, sits comfortably with synths and modules from a range of manufacturers — a practical detail that matters more than it sounds, since a stage piano that only plays nicely with its own brand's modules is a headache. The RD-300S splits, sends on dual channels, and turns Local control off for the upper and/or lower sections, which makes it a serviceable controller for a rack of outboard gear even if its internal voice count is limited to one.
Physically, the RD-300S is a substantial piece of kit. The 88-key version measures 55 15/16 × 18 1/8 × 5 1/8 inches and weighs 60 lbs, with a list price of $2,595 — a serious investment at the time, and a reminder that weighted-action digital pianos were not cheap in the late 1980s. The 76-key RD-250S, for comparison, ran $1,995 at 68 lbs, and the flagship RD-1000 (88 weighted wooden keys) carried no published US list price. The RD-300S sits in the middle of that family: full 88 keys, the newer SK-6 action, and the same S/A sound set as its siblings.
Roland's advertising made a pointed claim about the value proposition — that players should compare the S/A instruments to any sampled piano, "even those costing three times as much," and let their ears decide. That's marketing, not an independent verdict, but it does capture the pitch: this was Roland's argument that modeled synthesis could hold its own against sample-based rivals at a fraction of the cost. Mix (February 1988, p.43) carried the same S/A feature, reinforcing that the RD-300S was part of a coordinated launch rather than a one-off.
For collectors and players today, the RD-300S occupies an interesting niche. It's a genuine S/A-era Roland — the same chip family that made the RD-1000 and MKS-20 desirable — but in a more affordable, more common 88-key stage-piano format. The SK-6 action is the draw for anyone who wants a weighted keyboard with a piano-like feel without paying flagship money. The trade-offs are real: single internal sound, no pitch/mod wheels, no aftertouch, and a programming interface that requires patience. It's a player's piano, not a programmer's synth, and it should be bought as such. The 60-lb weight and 55 15/16-inch length mean it's a two-person lift and a commitment of floor space, so it suits a studio or a dedicated stage rig more than a cramped home setup. As with any instrument of this vintage, the action and the power supply are the things to check before buying — and the S/A sound, while distinctive, is of its era rather than a modern recreation.
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