Yamaha TX-802
FM Tone Generator (1988)

Yamaha DX-7 model II Rackmount module version adding great performance enhancements.

RACKMOUT MODULE 2 rack height units.
The main panel features a 40 x 2 lines LCD with active matrix backlight, 28 buttons and a slot for memory cartridge.

Back panel terminal connectors:
- Midi interface
- main signal out
- 8 individual analog out

Front panel terminal connectors:
- headphones.

VOICE main core 8-bits Hitachi HD63C03YP manages 16 voices polyphony.
The IC YM2604 OPSII (Operator-S same found on DX7 Mk2) ASIC chip generates 6 sinewave digital oscillators with individual volume, tuning and scaling levels.

Burr Brown PCM54HP D/A converter has been changed from classic Yamaha DX-7 / DX-5 previous BA922 for a clearer sound, especially on high frequencies.

FM SYNTHESIS Tx802 6 sinewave digital oscillators operators (or OP) organized as algorithms, assigned as carrier or modulator linked between them on different pathways interacting on their harmonic contents depending on the varable feedback strength.

- carrier: defines the amplitude and the spectral frequency - modulator: sets the sound timbre and the relative harmonic contents.

 

ALGORITHMS modules features 32 signal paths with frequency ratio or fixed frequency.
The output is fed back to its input with 7 different levels feedback, as rule of thumb: high values feedback results in richer harmonic contents.

PERFORMANCE original DX7 II multitimbric feature has been improved with no less than 8 parts with individual settings and playmodes:

- volume / panning - Midi channel - stack voices unison - voice assigment (a kind of voice rotate) - Microtuning:11 Scales presets and 1 editable users OP voice can be assigned to monophonic mode with variable portamento rate and variable random ptch fluctuation for a kind of analog feel.

LFO up to 2 modulators (shapes: sine, triangle, saw up/down, square and sample & hold) with adjustable start delay and sync retrigger:

- LFO PMD modulates pitch - LFO AMD processes the amplitude

ENVELOPE system is based on the YM3609 generates 7 EGs:

- 1 EG pitch: 4 segments + 4 times - 1 EG per OP (6 in total) 4 segments + 4 times. Another important function is the scaling level a very precise Key follower featuring 4 various linear or exponential curves with variable depth.

MIDI implementation features full Sysex editing but just a few basic CC # like pitch bend, modulation, breath or aftertouch.
TIP: A second TX unit can be linked for extra polyphony using the ODD-EVEN function.

MEMORY:

- 128 ROM voices - 64 RAM voices - 64 RAM performances, optional 16 Kb cartridge model RAM4 doubles vailable memory. - LEFT - battery replacement internal CR-2032 3V lithium battery soldered to the main board. - click to enlarge pic -

TIP TX-802 is compatible with DX-7 mk1 cartridges but different geometry requires a special adapter model ADP-1 to access to the vast library.

 

REPAIR common issue is crackling outputs, check out belows

 

 

OS is burnt on XB224- IC6 - a 27C256 eprom

DOWNLOAD LATEST OS BIN

 

EDITOR TX-802 has its own logic but still deep edit is not an easy task! fortunately there are a LOT of software editor for DX7 /DX7 MkII that cover 95% of functions:

Atari ST : Dx-android, Dx expert or caged ST (PIC) PC-based: Soundiver, Midiquest, DX-manager, Synlib and others. MSX: YRM 103-102 cartridge Voicing program / YRM304 IOS: Yamaha DX7/TX7/TX816 Editor (pic below).

RELATED FAMILY:

LINKS: TX802 - Tx816 - Tx7 - Sy99 - DX200 - DX5 -

 

VST PLUGIN / SAMPLED VERSION there are some free and commercial samples set:

-DEXED -HEXTER -MDA DX10 -OXE FM SYNTH -VX7

free

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