Triggers

A few people noticed something odd to the left of my Q119 sequencer from synthesizers.com. This is my trigger expander, basically I wanted something that would let me trigger noise shots, or toggle end points on the sequencer.

Now, synthesizers.com very kindly put a header on the back of the Q119 which brings out the key signals you need to do this, so adding an external trigger module was simply a case of reverse engineering the pin out and making a PCB.

D119 trigger PCB
D119 trigger PCB

This shows the PCB, and what I wanted to accomplish was that this was something people could make themselves rather than something I was going to sell. Why? well a number of reasons, I don’t honestly believe many people would be interested in buying and also the cost of the switches would make it quite an expensive module to sell, for what it does.

So I made it through hole, this was a huge pain in the butt, routing PCBs with surface mount parts is so much easier because you can run tracks under pads, with through hole, every track has to go between the holes. Add to this the fact I wanted to keep it 1U wide.

This PCB ended up being 4 layers, but is still quite cheap (4 layer PCBs from china only cost a couple of dollars more than 2 layer versions).

  • Rear of D119 PCB
  • D119 trigger PCB

You’ll need to be careful about the order in which you solder parts on, I’d suggest that the second to last is the switches and the final parts are the LEDs (so you can position them at the correct height.
You’ll also need to solder ground and output wires to the three connectors which are not mounted on the PCB.

In the ZIP file of the project I’ve included the schematics, gerbers and KiCAD files you need so you can make your own, or tweak the design as you see fit.

If I was to make these again, I would pretty much certainly make it surface mount to make it easier to route and this would make it cheaper to manufacture in quantity.

MuSeq Update

Another quick update for MuSeq, This time I’ve added the ability to set the “clock out” rate, so you can go from 1 clock per 4 beats all the way to 32 clocks per 4 beats. A short video is below

MuSeq Clock out demo

There are a few things left to do, so here’s a list;

  • Clock in from front panel (feed it say 8 clocks and get 24 PPQN resolution)
  • Self updating, i.e. you can update from SDCard
  • MIDI out
  • Sync 24 Out
  • Some internal tidying up of sequence loading/saving, particularly when in Bank play mode.
  • Redesign of PCB and Front Panel

The big hurdle is going to be the self updating, it always is. As it essentially requires you to boot into a bit of code to check for updates, then clear itself and load the main code, add in the ability to make it so you can’t brick it and things become quite difficult quite quickly.

The remainder should be straight forward, then it’s a case of getting prices and looking for a couple of beta testers before it can be shipped.

Moving Times

A number of things have been going on in the world and in my personal life. So I wanted to give a quick update.

The COVID-19 problems are really worrying and very stressful, to see so many people loosing their lives due a disease that can be stopped simply by avoiding social contact is so saddening.
Even sadder is that a portion of humanity seem to feel they’re immune, it’s a hoax or simple that it could never happen to them. So they carry on as before resulting in more avoidable deaths.
I’m finding the headlines increasingly painful and difficult to read.
I can only hope that the selfish people soon wake-up and start acting like responsible adults.
One thing is certain, this is a world changing event and our lives will never be the same. I my one hope for this crises is that humanity changes for the better going forward.

A personal update, I’ve recently moved home, this resulted in about 3 weeks of downtime for my development efforts and a lot of upheaval, things are almost back to normal for my working environment.

As a result of my move MuSeq work was on hold, I’ve only just started again. I discovered that the MIDI timing was a bit out, MuSeq was slightly ahead of the beat, so I fixed that and now it’s rock solid.
Bad news is I discovered a bug in the MIDI library I was using, it doesn’t run on an interrupt, so any event that happens like say changing from the CVA page to the CVB page means that some MIDI clock ticks are missed, resulting in a massively out of time sequence, which is really annoying to say the least.
I’ve had a look and it doesn’t look like it’s possible to modify the library to do this, so I’ll be writing my own library for handling MIDI using interrupts. Not a big problem, just a lot of code that will need stripping out and refactoring.

I’ve got a new module in the works. This is something I’ve had in breadboard for about 4 months, and I got the prototype PCBs early march (delayed due to COVID-19). You can hear a quick clip of the new module here;

The module is based on the somewhat infamous Korg NJM2069 VCF/VCA chip used in the Poly 800, DW6000/8000 and DSS1, here’s a picture;

This is only going to be available in the MU format because there are a plethora of really great VCFs for euro-rack, but only a limited range in MU format.
Some of the nice things about this module is that it has a built in VCA, so for people with smaller rigs where space is an issue this module works really well as a “dual function” module.
I’ve also added a switch so you can select 24dB/Oct or 12dB/Oct cut off slopes.
Of course, being designed for a poly synth means the resonance is CV controllable which is a real boon (one of my favourite tricks is to route VCF envelope to both cut off and resonance).
Finally on the back there are jumpers which can be opened and a header cable can be added to bring out the extra two pre VCF inputs and VCAs. I may do an expansion module for this to bring those extras in.

Now the catch, I only managed to get 25 of these NOS (New Old Stock) from a retailer who sells NOS chips, I would love to get more and maybe if I can find some I will. However, this run (when I find my oven for baking PCBs) will be limited to 25 only. I’ve tested these chips and they all work perfectly.
However, I will be publishing me schematics, gerbers and front panel design, so you can make your own if you’re lucky enough to find one of these incredible sounding chips.

For now, please, stay safe and look after yourself and your loved ones, humanity has had some major crises in it’s existence, we will get through this one too.