Yamaha DX21
Digital Programmable Algorithm Synthesizer (1985)

 

Bi-timbric budget spinoff from classic 6 OP DX7 machines with special analog chorus board.

SYNTHESIZER 61 Keys.
Main pannel features a LCD display (no backlit) , 2 wheels for modulation and pitch bender, 3 sliders and 42 rubber buttons.

Rear panel terminal connectors:
- stereo main out (or individual for bitimbric mode)
- sustain footswitch input
- portamento footswitch input
- damper footswitch input
- headphones out
- Midi interface
- tape interface
- breath controller input (original is BC1)

 

 

VOICE CPU is a HD63803XP Hitachi which manages 8 voices - DAC is based on a IC YM3012. The DX21 IC chip YM2164 features 4 OP + 8 combinations called "algorithms"; previous DX7 synthesis is based on more advanced 6 OP system + 32 combinations algorithms.

 

 

SYNTHESIS there are 4 sinewave operators organized as algorithms, assigned as carrier or modulator, linked between them on different pathways interacting on their harmonic contents depending on the variable feedback strength.
- carrier defines the amplitude and the spectral frequency
- modulator sets the sound timbre and the relative harmonic contents.

ALGORITHMS Dx21 features 8 combinations algorithms with frequency ratio or fixed frequency: the output is fed back to its input with 7 feedback levels , as general rule, high values feedback results in richer harmonic contents.

 

PERFORMANCE system some special performance play:
- poly / mono mode
- portamento set with time
- pitch bender range
- mode wheel r range
- breath controller setting (destination / range)
- dual / split mode: two sounds can be layered (only one from bank A and the other from B) with a detune ratio - the BALANCE sliders adjusts the volume between the 2 sounds. Note that LFO from patch 1 rules on second one.

 

 

LFO there are 2 delayed modulators (frequency range from 0.007 Hz to 50 Hz):
- LFO1 amplitude
- LFO2 pitch.
Both modulators can be set to retrigger mode and feature 4 shapes: saw, square, triangle and sample & hold.

 

 

ENVELOPE 4 EGs: each OP features 1 amplitude EG (4-segments) + 1 general shift. Very simple Key tracking scale less sophisticated than previous DX line.

 

 

EFFECT internal analog chorus based on a single Panasonic BBD IC MN3209 with no control but ON OFF- pseudo stereo gives a nice warmth to the sound.

 

MEMORY:
- 32 RAM patches (bank A + bank B)
- 128 ROM (must be loaded by 16 groups or individually).
Sounds can be saved to either Sysex dump or magnetic tape.
Battery replacement: a 3V cr2032 soldered to main board - you have to open the machine, the first board on upper right side is the right one.

 

 

EDITOR there are many computer-based editors:
- Ctrlr (free)
- Midiquest ($$)
- noize ($$)
- FOUR FM (free MAC)
- VSTizer ($$)
- Atari: YSEDITOR , Steinberg synthwork (PIC) , caged 4 OP artist.
- DX21 editor (IOS) pic below

 

 

RELATED FAMILY 4 OP:

DX-9 (1983) first 4 OP incompatible with other 4 Op DX line VIDEO	TX81z (1985) a kind of Dx100 module with harmonic variations.	DX-100 (1985) same as dx21 with minikeyss VIDEO	DX-27 (1985) simplier DX 21 version - also a "S" with speakers VIDEO
Fb-01 (1986) simple 4OP module VIDEO	DX-11 (1986) a Tx81z version with 8 waves VIDEO	YS-200 (1988) : consumer 4 Op version with sequencer VIDEO	V-50 (1989) top 4 op series with sequencer and drum machine VIDEO

Also: - YS-100 is a YS200 minus sequencer
- TQ-5 is a laptop version
- B-200 with internal speakers
- Korg Z3 Guitar Synthesizer.

 

VST PLUGIN / SAMPLED VERSION there is no official VST emulation, however here's some FM emulator (6 or 4 OP)

name price download demo polynominal free 4 OP sample pack! 65 mb free samples: - FM FARFISA - DX TINES - MELLOW SQUARE -LATELY BASS Free donation: n/a -DEXED -MDA DX10 -OXE FM SYNTH -VX7 -HEXTER free VST   FM HEAVEN Commercial VST imports both DX7 and DX21 patches

 

AUDIO DEMO

Seq: FM + sampled drums 1 Seq: FM + sampled drums 2 Seq: FM + sampled drums 3 Seq: FM + sampled drums 4 Seq: FM + sampled drums 5 Seq: FM + sampled drums 6 PIANO : DX tine rhodes PIANO "FM grand piano" PIANO: dx21 chorus mode PIANO: celesta chorus mode BELLS: DX Big bells BELLS: dual chorused BRASS: me PLUCK: koto? ORGAN: light my Farfisa PAD: dune SYNTH: LFO dx21 SYNTH: clean dual

BASS: solid bass aka lately bass* BASS: EBM bass BASS: loud bass BASS: Sh101? Bass: bass dual + balancing SYNTH: da minimoog D SYNTH: 8 bits AY SYSTEM SYNTH: LUCY FX : weird noises FX L: fixed frequency FX : lately bass destruction FX : LFO FX : bubble subbass FX: bells chorus mode FX: noise DUAL MODE   XP: chorus off then on XP: DUAL mode detune range

* check out Lately bass dedicated page

 

VIDEO CLIP SELECTION Demo demo2 demo3