Yamaha RX-7 (1988)
Digital Rhythm Programmer

Digital drum machine based on low-fidelity samples, 24 dynamic pads and internal sequencer.

DRUM MACHINE Main panel features 16 X 2 lines display, 24 dynamic pads, 4 sliders and 36 buttons.

Back panel terminal connectors:
- Midi interface
- tape interface
- main signal out +- headphones out
- metronome click out
- assignable pedalswitch
- data cartridge slot memory expansion (only data)

Power supply external PSU 12V +)- polarity original model is PA-1210.

 

TECH a 8 bits MPU model HD63C03YP manages up to 16 voices polyphony mainly based on custom wave generator YM2409 (same found on sampler TX16W). OS burnt into TC571001D-20 CMOS Eprom. Each RX7 voice is assigned to a PCM sample each with some sound edit parameters:

- pitch tuning - audio level setting - stereo panning - delay start wave - sound decay: repeats the note thus decreases polyphony, as the core does not feature any FX DSP engine inside.

WAVETABLE internal ROM contains 100 PCM waves at 12-bits resolution, mainly drum percussions but also some bass sounds, brass hits and some synth sampled from classic FM keyboard Yamaha DX7.

The PCM wavetable is organized into 15 category groups: electric, fusion, high, heavy,hihat, high open, high mute, jazz, low, processed, percussion, reverse,Fx and snare.

EDIT RX panel is quite clear but programming is intricate with single function JOB.

There is quite nothing to externally edit the RX7 with computer but an old retro program by Yamaha YRM302 RX EDITOR for 8 bits computers MSX (although it is optimized for models rx11/15/21).

 

LFO a single triangle modulator- frequency range from 3,4 to 78 Hz

- PMD = LFO to Pitch - AMD = LFO to Amplitude.

SEQUENCER patterns can be written using either pads or external Midi devices:

- realtime with quantizes 1/96 resolution + 5 swing models (levels: 54% / 58% / 63% / 67% / 71%) - step by step classic entry. HEAR pattern

MIDI Sequencer and pads send Midi OUT messages and special Chromatic mode allows to play a sample at different pitches just like a synth patch.
SYNC tempo can be set by 3 sources:

- internal frequency from 20 to 250 BPM - external Midi clock - tape sync protocol.

MEMORY:

- 5 ROM kits - 5 RAM kits - 100 patterns (max 99 measure) - 20 songs (max 999 parts) - 3 chains (max 90 steps). LEFT : Battery replacement: soldered Lithium battery 3V Cr-2032. Internal memory can be doubled using RAM4 memory cartridge, same used by DX7 Mk2 or Tx802 FM module expander. - click for bigger picture -

 

RX-7 MODIFICATION as many digital drums, the RX is doomed to circuit bending experimentation

LEFT - pic from EBAY auction: circuit bending machine <- click for video demo-

RELATED RX FAMILY:

RX11 first of the series	RX15 improved rx11	RX21 different soundset	RX21L same as RX17 latin-oriented
RX17 halfway between RX21 and RX21L	RX120 a preset pattern version of 21	RX5 flagship with mixer less sounds than RX7	RX8 first with 16 bits sample

VST PLUGIN / SAMPLED VERSION no official Yamaha plugin, but there are some free samples set:

Martin78

free sample pack

GALLERY:

mimì the synthcat	custom rx7 ebay	original advert	hi res pic

DEMO: RX17 megamix internal pattern 1 internal pattern 2 internal pattern 3 all bassdrum sounds all hihats sounds all reverse sounds all snare sounfs

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