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Last update: 28.10.1999

Roland A-80 midi keyboard controller

Roland A-50 midi keyboard controller

Roland A-80 & A-50 aftertouch modification

I haven't tried this modification myself, so I do not guarantee this fix will work. Aftertouch may be too heavy on some earlier units. Too much pressure is needed to get aftertouch to send values ranging 100-127. Roland has announced fix for that, which consist replacing resistor with another of different value. This is done by following way:

Replace 5.6k resistor R 45 on Main A board with 10k resistor.

If you don't get satisfactory results, you may experiment with different values. On later models Roland has already made the modification at the factory.


Seems that the information above is erratic. The version below has tested in real life with A-80. (Again not by me.)

According to the service notes, R43 is 5.6k for A-80 and 18k for A-50.
Its value determines the current that flows through the aftertouch sensors.
R45 is 18k.
Therefore R43 is the resistor you should replace.

Roland A-80

Roland A-80 has true polyphonic aftertouch and weighted keys. There is only very few 88-key weighted midi keyboard controllers, that send polyphonic aftertouch. On the new Roland A-90 controller, polyphonic aftertouch is merely emulated by software: it can affect the highest, lowest, first or last note played - but it does not have true polyphonic aftertouch implemented in hardware level, which would require own pressure-sensitive sensor under each key.

The keyboard feel is a matter of taste. Personally, I can not imagine how to make Roland-action much better, within the current midi standard limitations (only 128 values). There is four parameter settings for velocity curve (curve, scale, offset, holdoff) and aftertouch curve (curve, scale, holdoff, type). You can split/layer the keyboard into 4 zones and each zone may have different velocity/aftertouch settings. These are easy to setup with buttons, sliders and large graphical display.

The keyboard build quality is extremely good. My unit has been in heavy use for almost decade, still the keyboard action is faultless and the housing/chassis do not give any resonating noises even if you hit the keys hard.

As a midi-controller, A-80 is versatile and has enough capabilities. However, it shows its age in its midi implementation, which is dated late 80's. For example, it does not support bank-select commands, so you need to use SysEx dumps and store these into A-80 memory or arrange your setup so that you do not need to change banks.

Up to 64 patches can be stored into A-80's internal memory. These can contain A-80's own settings and about 13000 bytes of SysEx data for external midi devices. For easy access, you can combine 32 patches into one Chain. You can have up to 32 Chains. You can save and load A-80's memory via midi or by using optional memory cards (M-256D, M-256E).

An exact copy from MIDI IN1 is send through 4 midi out sockets and MIDI THRU socket. A-80 can send data you input via its keyboard to four different midi channels. The data from MIDI IN2(Remote)is received in OMNI ON mode and merged with the output of A-80's keyboard. Each MIDI OUT socket sends the same MIDI data.

On negative side. The unit is heavy, with case the unit weights over 40 kg. The otherwise good graphical display may become noisy when old. My unit is pretty quiet. The A-50 I also own uses the same type of display and it gives noticeable high-pitched sound, which comes from the backlit display. It might be possible to get rid of this noise by disabling the backlit, which probably turns the display difficult to read without external light source. If you decide to make the fix mentioned above, you may find that after doing it, the aftertouch is still too heavy to use. (Some A-80 users have presented ideas of rising the aftertouch stripe slightly or replacing the felt with thicker one, to make it more responsive. I don't know how good results you get by doing that.) And if you ever need to replace the poly aftertouch stripe(s), it may cost significantly more than a channel aftertouch stripe.

Roland A-80 musicians

George Duke/his band owned A-80 # 2C63478. It has reported to be stolen in 1994.
Peter Lemer (January 1998) "I've replaced the KX88 with a Roland A80 (because it has polyphonic aftertouch)."

Roland A-50

Roland A-50 is 76 synth-type key version of A-80 midi keyboard controller. What I wrote about A-80, is also relevant for A-50. Like A-80, A-50 also has polyphonic aftertouch. They share the same electronic parts and the same service modification will work with A-50 also.

Roland A-50 musicians

In the early nineties, Vince Clarke seemed to be happy controlling his gig-rig with A-50. (February 1990/KEYBOARD magazine)

Thanks to Ingo Debus for additional information and corrections.
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