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MIDI Hardware
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Topic starter
I'm just getting back into MIDI after a LONG outage and am attempting to connect my Casio MT240 keyboard to a Linux netbook. The Casio has 5-pin DIN connections and the netbook is USB so I've bought a DIN/USB converter. Driving the Casio from a software step sequencer works fine. However, driving a software synth (Zynaddsubfx) from the Casio keyboard exhibits the strange phenomenon that only a single Note Event gets sent, changing the Program on the Casio (ie the keyboard sound) sends a program change event after which another single note event can be sent. This is totally repeatable and so far I have not been able to send more than one note event (off or on, Midi mode 3) without changing the program/keyboard sound.
To me this seems like a Casio bug either hardware or firmware. I've used a software MIDI monitor (Kmidimon) which confirms the description above. Any suggestions? as it's an old (aka vintage) keyboard it could be a first generation midi chip (or even custom firmware to do it), perhaps upgrades are possible. I don't feel inclined to take the lid off the machine and delve into it, though as this model seems to be a favourite target of the circuit-bending community there may well be possibilities to do so. All suggestions gratefully received (I know I can buy current generation MIDI keyboards, but that seems a bit defeatist at this stage).
Posted : 30/08/2021 12:28 pm
Check one of the posts before this one. I'll echo the most important thing to check first: what is the cable/adapter that you bought? The generic one you find online and in some shops works with certain devices and causes lots of issues with others. There is a "recommended" one that is mentioned in several other posts (including one in the past week or two... sorry, replying on my phone ad it's hard to check for the post without nuking what I'm typing...) I believe it's a Roland adapter?
Posted : 30/08/2021 12:53 pm
Another user has a similar problem: https://www.midi.org/forum/10426-converting-keybaord-playing-to-midi-file-on-pc
The culprit seems to be a USB MIDI adapter, a cheap low quality thing, that doesn't respect the specifications
https://karusisemus.wordpress.com/2017/01/02/cheap-usb-midi-cable-how-to-modify-it/
Posted : 31/08/2021 12:22 am
Topic starter
Thanks to both respondents.
The culprit is the cheap adapter, identified as CH345 on my Linux patch panel so in all likelihood built on the notorious CH345 chip which has lots of operational features (aka bugs). Examination with a scope indicates MIDI events are sent by the keyboard when expected but not processed by the adapter. Given that some of the messages get through (see original post), I don't think doing the 'opto isolator modification' is going to sort it, in fact the pcb of my converter doesn't have a space for an opto so perhaps they've changed the design to reduce costs. I'm now on the look out for a better adapter which isn't based on the CH345 chip, any recommendations? It's a sad fact that it will in all probability be cheaper to buy a new USB/MIDI keyboard than an adapter, the only advantage with using the MT240 is it's got a 4 octave keyboard compared to the 2 on smoe models.
Posted : 06/09/2021 11:32 am
Roland makes an adapter that seems to be the go-to for solving everyone's issues 🙂
Roland UM-One
https://www.roland.com/us/products/um-one_mk2/
A search showed that they carry it at Guitar Center, or it can be purchased elsewhere online.
Posted : 06/09/2021 12:28 pm
Topic starter
Postscript: Purchased a Roland UM-ONE and it worked out of the box and the Casio keyboard now works fine with my Linux netbook. Thanks to respondents.
Posted : 10/09/2021 1:05 am
Thanks to you too for using Kmidimon! I'm the author 😉
Posted : 10/09/2021 9:46 am
