New Sequencer Nearing Completion & All In One Update

A project log for OPL Studio - OPL2 / OPL3 MIDI Synthesizer

The ultimate dual OPL3 MIDI syntesizer with touch screen

maarten-janssenMaarten Janssen 11/14/2023 at 13:570 Comments

The new sequencer is nearing completion. All functionality has been implemented and many bugs have already been fixed. The newest additions since the last log are:

Drum sequences are still not using the new sequencer and I will definitely leave that until after the new software update. I now just want to release this thing after a few more days of testing to capture as many bugs as I can.

Next to the sequencer update there will be a fun little secret hidden in the new software ;)

Update On The All In One Units

I have some good news on the all in one units this time. When using the line out the audio is now fine. No more excessive noise from the different components. The amplifier to the speaker out is still a problem, but I think I also have that mostly covered now. I've been working on a different amplifier design using a different chip that as far as I've been able to test sounds promising. I have a little test amplifier breakout board on the way to test my new design before I integrate it into the main PCB.

For the LCD module I also have some new plans. So far I've been using complete modules for the LCD and touch panel that also include an SD card socket. The problem I'm having with these modules is that too often they are of questionable quality where some have brightness issues, some of them have misaligned touch screen panels, others have issues with adhesion of the different layers of the LCD and so on. This means that for every OPL Studio I've been shipping so far I've been hand picking the LCD modules to make sure they function correctly. This also means that I've been rejecting far too many modules (around 25%) and then I'm not even counting all modules that arrive broken due to aweful packaging done by vendors. Anyway, to get a better grip on LCD quality I will change to building the modules myself or rather I will use the loose LCD + touch panels that connect to the main PCB using a ribbon cable and I will build the interface myself. I have a few panels on the way to test this out.

Finally the enclosure will also get an update, though it will keep the same dimensions and overall look as the current units.