More modules complete.
Oh the joys of a well stocked parts bin! Dull and frustrating as it was, the period I spent just amassing parts is now bearing fruits. I can just get on and build all these project I’ve had on the go for so long now. It’s also been quite a blessing as funds have been quite tight recently but I’ve just been able to get on with things.
So here’s an update on the latest modules I’ve completed. I’m still building them with makeshift panels for now. Some with plywood and some in a red plastic which once formed a promotional shelf overlay in the spirit aisle at Sainsbury’s. It’s always pained me how much waste we produce with the promotional material we get through so anything that’s being chucked that I can use comes home with me. Sadly the red plastic isn’t quite rigid enough in the long term, but for a prototype it’s absolutely fine.
MegaOhm VCA Rider
The boards for these were already assembled so it was just a case of testing out my panel layout and doing the wiring. I’ve only made up one panel assembly so far as I only have a limited number of jack sockets and this takes ten. I’ve been able to test both boards with it though. Both boards worked first time, Not that there’s much to go wrong with these.
I’ll probably see if I can get a few more of these at some point although they do take up a fair amount of panel space, although this is justified by their versatility. I’m keeping an eye out for some simpler VCA’s however with just basic functionality that can be built with multiple units in a compact space.
As before, this board was fully stuffed and awaiting wiring to a panel. There are two unused holes in the pane where I decided not to implement the CV level controls, but as this is a test panel it doesn’t matter. Better to discover I didn’t want these now rather than on a finished panel.
I decided I’d rather use an external attenuator if needed and give myself more panel space on the module. So far in playing with the module I haven’t needed to adjust the CV level. The only other modification I made was to normalise CV B input to CV A so that one input could control both channels.
I knew this module would have a distinctive sound of its own but until I plugged it in I didn’t really know what to expect. I have to say I’m very pleased with it. It does produce a wide range of strange metallic sounds, well suited for cymbals and hi-hats, but once you start adding control voltages it takes this module to a different level.
It’s probably better to let you listen to the results rather than me try and describe it.
This will probably be the only one of these I build as I can’t see a need for more in my system. But of course you never can tell.
Ian Fritz AR/AD Envelope Generator and Pulse Delay/Stretcher.
This is a great little circuit combining different useful functions. I’ve built this one up on stripboard and added a few modifications of my own.
There are two main parts of the circuit. First we have a simple envelope generator. This is a particularly useful circuit as the envelope just requires a trigger pulse to start it and complete a cycle unlike other circuits which require a gate signal. It will take a gate signal and will extend its fully on state dependent on the gate length. I’ve also added an additional comparator input into the envelope as I could get a TL072 in the same space as a TL071 and it seemed a good addition!
The second half of the circuit is the Pulse Delay/Stretcher. This takes a gate or trigger input, holds it for a defined length of time and then produces a gate signal of a defined time. This can be fed to the envelope generator by means of a switch and also the gate has an output on the front panel for use as a control voltage elsewhere.
By feeding the envelope with inputs from both sources some pretty interesting rhythmic effects can be achieved.
Thomas Henry Controller LFO
I already had the panel ready to go for this so again it was just a simple wiring job. I’ve been having a lot of fun playing with this since I built it and even though I understood all the functions it offered it’s different actually being able to play with this. When used with Ian Fritz’s AR/AD Envelope generator and Pulse Delay/Stretcher I’ve been able to create some great rhythmic patterns.
Having played with it for a while now I have decided to modify two of the four boards I have to give much slower rates as in it’s current form the lowest speed is far to fast for the slowly evolving modulations I’d also like to use these for. Luckily it’s just a case of adding a switch and a couple of capacitors and changing the panel to accommodate.
Anyway, here’s some recordings of me playing. I’ve had so much fun with just the modules so far I haven’t got round to connecting to an external sequencer.
The kick is the mega percussion synth triggered by the LFO which also triggers the envelope generator which in turn controls the Liquid HiHat being fed through the VCA.
Mega percussion synth triggered by the LFO with the voice modulated by the triangle out from the LFO mixed with the envelope generators output.
Same set-up as above but with square out from the LFO mixed with the gate output form the envelope generator.
As above but with a short decay on the mega percussion synth and adjustment to the pitch.
As you may have noticed from the first image in this post, I’ve built myself a makeshift case for everything until I can afford to make a proper case. It’s the result of a bit of wood from the DIY store and a few offcuts I already had lurking in my flat. It isn’t pretty but serves a purpose for now – although rather alarmingly I seem to be running out of space already!
Next on the agenda is to get one of my oscillators working. I’ve deliberately left these as they are a bit more complicated and will take a bit of setting up when complete. Also, it seemed pointless to build them with nothing to modulate or shape the sound with.
I’m also working on a stripboard layout for the mighty Wasp filter. This filter is based on a CMOS logic chip has a great reputation and distinctive sound. It will be my first filter as I seem to have been collecting a glut of oscillator circuits so far. Mainly because they were offered as boards and the opportunity was to good to miss 🙂