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Oberheim DMX





oberheim dmx

info Country: USA
Weight: 5,5 Kg
Dimensions: 45,7 X 30 X 12,7 cm
audio demo trend price : 700€
manual demo comments

Oberheim DMX
Programmable Digital Drum Machine (1981)


Classic American drum machine based on primitive 8-bits samples but great sound: this is the history of eighties music from New Order to Run DMC.

dmx logo

info DRUM MACHINE The main panel features a flurescent display, 10 sliders for volumes mixing, 24 buttons for edit and 18 trigger pads with no velocity.

Back panel terminal connectors:
- 12 separate mono analog out
- 2 pedalswitch inputs for start-stop and NEXT pattern
- sync tape interface
- external clock I/O
- switch tab for memory protection
- tape interface
- custom 3 x 4 molex connectors: the 1st molex row is TRIGGER IN and each instruments can be controlled by a simple pulse (range +1-5V).


edit VOICE main CPU based on a Z80 Zilog manages 8 slot-in voice boards; all boards have a trimmer for pitch tuning.

zilog z80

edit Each voice board contain various 4 kb EPROM model 2732 with companded 8-bits digitalized sounds and some longer sounds (like crash) take a total of 16 kb split in 4 x 2732 EPROM.

demo pitch tuning from trimmer LISTEN


it is also possible to use different sets of boards, many were available at that time or directly burn the EPROM memories with new samples.

pitch eprom

edit some earlier DMX models have a tom board which lacks the famous CEM IC.

demo LISTEN various eprom sounds

24 sounds derived from the PCM EPROM combined in various pitches:

- bass drum: loud / medium / soft
- crash cymbal
- snares: loud / medium / soft
- tambourines: loud / soft
- hi-hats: close / accent / open
- toms: from high to low pitch
- shakers: loud / soft
- ride cymbals: loud / soft
- handclap
- rimshot.

pitch eprom

edit CV the second molex labeled "CV IN" changes samples pitches within a 0-6V range.
Some third-part sellers build some early Midi trigger system.

trigger cv gate

works in 2 main modes:
- real time with metronome (variable dividers) and correction-quantisation from 1/48 to 1/4 note.
- step by step: just entry pauses or notes between 1/4 value and 1/48.
Other functions for edit like COPY, OVERDUB, ERASE notes/ patterns/ songs/ instruments or variable time signature.

dmx record

editSYNC tempo can be set with internal clock from 25 to 250 BPM or slaved to SYNC TAPE or trigger input pulse at 96 PPQ (not so common).


edit MEMORY is non-volatile:

DMX memory board

- 2000 events
- 100 sequences
- 50 songs.

A special board clipped to the Z80 doubles internal memory; this board usually "updates" to OS 3.1 which adds some new sequencer functions. Also a third-part MIDI interface can be added with some hardware modification.

edit early DMX CEM LESS, upgraded to 3.0 OS with extra patterns memory board. Click to enlarge pic



edit OS is burnt in 2 eproms:

OS eprom

- DMX 1.0

- DMX 2.21

- DMX 3.20 (for memory EXP)

- DMX 4.01 (for midi)



edit MAINTENANCE there are 2 common issues out of 2 models I owned:

battery replacement

- BATTERY: internal rechargeable battery just leaks on the circuits and damage the nearby ICs logics; often the first symptom is troubles with unstable clock frequency.

editbattery leakage repair

dmx display module

- DISPLAY :often some display modules fail and some gibberish characters appear - found some spare parts on Ebay at *EVIL* price.

editsecond module failure!

Faulty display module replacement (there are 4)



obehreim DX

DX - was the successive economic version of DMX with different sample and a single board for voice samples.
Some of the US versions were Midi factory upgraded.


original scan original scan original scan
original scan original scan
original advert   m3r artwork 1    



oberheim dmx drum machine

Company: Oberheim
Model: DMX
Class: Drum machine
Dates: 1981
PADS: 18
Synthesis: PCM

Display: VFD
Polyphony: 8 channels
Sounds: 24 PCM
Resolution: 8 bits
Sequencer: 2000 events
Quantization: 1/48 to 1/4
Tempo: 25-300 BPM
Sync: at 99 PPQ

Memory: 2000 events
OS: latest is V4.01
CPU: Z80



demo OB DMX + Bass station II
demo pattern demo1
demo rhythm pattern 2
demo pattern demo1

demohave some DMX





Power supply

DMX exists in both 110V and 220V version with VOLTAGE inversion internal switch -CHECK IT ANYWAY! - open the box and it is straight on the AC.




edit Sample SHOP
edit Report Error

dmx banner

DMX voice cards for sale
DMX original Soundboards for sale!






new order dmx
video Blue monday with Oberheim DMX
oberheim logo mainboard DMX EPROMS DMX
award award
LOFI Old school king


REVIEW "Not as popular as Linn drum, but Classy vintage drum machine with great sequencer. You might be interested also in cheaper SCI drumtraks"

manual manual
-Sequencer -Sync
- getting pricey

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Oberheim DMX 4.0 out of 5 based on 15 ratings. price €700