Idea for Yamaha to have automatically more sustain on piano sounds

[Lionel N]

Hello,

[...]
The (entry level) PSS-A50 does not provide any sustain pedal connectivity. Whereas the (mid-level) Reface series provide it.
These keyboards are intended to be used at any place ("or even sitting in the passenger seat on a long road trip").
Therefore, you won't connect a pedal, but it would be fun to have a viable sustain feature.

The PSS-A50 has a "Sustain" button on the front panel, but using it usually results in a mess because everything is melted together. The chords that match, but also the one that don't match.
[...]

Lionel.

I'm happy to share that I finalized a HW mod and SW patch in order to be able to connect and use a real sustain Pedal on the PSS-A50.
Everything is working as any Sustain Pedal works on any equipped Yamaha Keyboard. All features are still present, no sacrifice. MIDI message sent is even the one related to Sustain Pedal (while the genuine "Sustain" button on the front panel sent a -sound- "Release time" message.
It works fine with or without headphones, USB or battery powered.

HW mod is quite simple, adding a 3.5mm jack on the PSS-A50 (then, an adaptator cable 3.5mm - 6.25mm is required to plug the Pedal), and 2 resistors (one 22k below the headphones connector (bottom PCB needs to be scratched in order to separate a pin from the Ground), and a 33k in serial with the new Sustain Jack.

Since no I/O was available, my idea was to use the analog input normally used to detect the HeadPhones Jack.

Since it's an analog input, it is able to measure and make the diffference depending on the voltage value measured. Thanks to the new resistors, this voltage changes depending on the combination "HeadPhones plugged/unplugged" and "Sustain Pedal pressed/released". Then, a SW patch shall be able to activate the right functions depending on the combinations.

SW patch was more tricky. No information was available. Nothing about the µC/SOC and the tone generator, nothing about the mapping, the registers... NOTHING.

A lot of retro-enginnering was required to identify the entry points. Sustain management was already present in the software, but not "connected" to the right functions since on PSS-A50, no more I/O was available for that (at the opposite of the PSR-F51 for which the Port C0 was still available and functional).

Full video to come later.
http://youtube.com/post/UgkxpGu8u1BeEL0fGrl-zsjeN36DrOPebMzP?si=1-DtNMS8jJ2rIKOs