Yamaha RX15 (1984)
A $495 drum machine that put PCM samples and MIDI in reach of working musicians — and left out the tuning knob.
Overview
The RX15 arrived at a moment when drum machines were splitting into two camps: expensive digital machines with changeable voice chips and cheaper units that simply committed a fixed set of sounds to memory. Yamaha's answer was to go digital on a budget. Both the RX15 and its bigger sibling, the RX11, stored their percussion sounds as 8-bit pulse-code-modulation samples in 256K of memory. That put the RX15 into the same technological conversation as the Linn and Oberheim machines — at a fraction of their cost.
The price told the story. Modern Recording (July 1985, p.58) listed the RX15 at $495, while the same issue put the expanded RX11 at a higher figure. A contemporary buying guide in Canadian Musician placed the RX11 at $1,100 and the RX15 at $750 north of the border — and, in the same breath, noted that machines like the Linndrum and Oberheim DMX were priced in excess of $3,500. For a musician who wanted sampled drums and MIDI sync without remortgaging the studio, the RX15 was the entry point.
What the money bought was a slimline black case roughly 14 by 8 by 2 inches — a deliberate break from the wooden end cheeks that competing machines still wore — with a 16-character alphanumeric LCD borrowed in spirit from Yamaha's DX keyboards. The layout earned praise for its soft-touch voice selectors and colour coding. This was a machine designed to be programmed, not just triggered.
The RX15's sound set ran to 13 instruments. The RX11 carried 16, and the difference was where Yamaha drew the line between the two models. The shared roster covered two bass drums, two snares, rimshot, two hi-hats, four toms, two cymbals, clap, cowbell and shaker. The fast attack of the samples gave the sounds a bright edge, with the four toms separately sampled and rendered with authentic results.
Memory and sequencing were shared between the two machines: 100 patterns, 10 songs, and 255 steps per song. Programming could be done in step time or real time, from the unit's own controls or from an external keyboard such as a DX7, with six note resolutions on offer and tempo changes programmed via a vertical fader and stored for instant recall. Both models offered stereo operation with separate left and right output jacks, plus individually settable and storable volume levels and accent per instrument. A footswitch handled start/stop, and a headphone jack allowed silent programming.
The MIDI implementation was the RX15's real argument. Both machines carried MIDI In and Out DIN connections, replacing the trigger jacks of older drum machines and allowing programming, remote control from a DX or MIDI keyboard, and synchronisation with MIDI-equipped sequencers. Linked to a DX7, the pressure and velocity sensitivity of the keyboard made dynamic volume control of every drum sound possible. The trade-off was plain: dropping conventional trigger and gate connections meant syncing to non-MIDI gear required an add-on interface box. The magazine also warned that Yamaha should advance the release dates or risk being beaten to the punch by competitors.
The omission that drew the most criticism was tuning. The lack of any instrument tuning facility was called "a vital omission and maybe a hazardous one too," and a later roundup in Canadian Musician confirmed that the RX15, alongside the RX11, Roland 707, and Korg Super Drums, offered neither tuning nor alternate sound capabilities. Where Linn and Oberheim owners could swap voice chips or trim individual sounds, RX15 users were stuck with the factory samples. Tape dump of program data was possible through mini-jacks on both models, though the RAM cartridge storage of the RX11 was reserved for the more expensive machine.
There was one workaround for players hungry for more patterns: third-party rhythm libraries. A Canadian Musician advertisement offered drum rhythm pattern libraries on data cassette for the RX11, RX15, RX21 and TR707 at $29.95, covering Top 40, Latin, blues, swing, rock, jazz, funk and country. It was a small sign that the RX15 had found enough of an install base to attract aftermarket support.
Collectors approaching an RX15 today should expect a machine defined by its compromises as much as its capabilities. The 13 fixed sounds and absence of tuning make it a period piece rather than a flexible studio tool, and the MIDI-only sync path limits integration with older gear. But the PCM samples, the 100-pattern memory, and the sub-$500 original price make it a genuine artifact of the moment digital drums became affordable — and a natural companion to the DX7 it was built to talk to.
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