vidiotsquad » Audio Synthesis

Sequential circuits sixtrak

bod — Wed, 17 Nov 2010 19:52:04 +0000

I picked up an old sixtrak for a decent price, mainly because it wasn’t working. For some reason there is no audio output, but thankfully all the important ic’s are there, mainly the cem3394′s which cost around £35 a piece these days!

With a little tlc and a good probing with the scope, I recon it’s going to be an easy fixer upper!

xr2209

bod — Thu, 12 Aug 2010 12:51:56 +0000

these wee vco ic’s are really good, i dont know why more people dont use them! other than the obviously limitations of linear response and reverse voltage control, i have yet to encounter any major issues.

with a bit of tinkering and snuffling (i have man-flu remember?), i can achieve a good range between 24hz and 1703hz with out any distortion, using only 9 components, which should lend itself nicely to to little drum synths and a replacement to the integrator/comparator vco i was using for the dub siren.

now where did i leave the co-codamol?

new stuff to play with

bod — Wed, 11 Aug 2010 10:58:46 +0000

off work today suffering with man-flu….. which is good (in some ways) as i just received a few ssm2164 and xr2209 ic’s, however i really cant be bothered unwrapping myself from the blanket and falling off the couch to go and experiment with them, so instead i shall be perusing the datasheets from the comfort of my warm little bubble of illness and consuming gallons of lemsips, water and chomping through some paracetamols.

things on the list to build with these:

ssm2164:

vca’s (linear and exponential response)
sinewave vco’s
4 pole low pass vcf
and i might splash out and buy a thomas henry mankato pcb from magic smoke

xr2209:

vco’s (obviously)
er….. thats about it.

the xr2209 is similar to the now discontinued, expensive and hard to find 566 vco ic, so it’ll be interesting to see how this wee blighter copes. it only has linear response but i’m hoping it’ll make a good substitute for the vco in the dub sirens. i’ve built nearly 30 of those now and have depleted the stock of pcb’s i had for them, but the parts count was huge for what should be a simple circuit, plus these are still analogue, which we all love don’t we?!

i think i’ll lie down again before i fall over….

Tunes

bod — Mon, 09 Aug 2010 08:13:41 +0000

One happy customer has sent a link for a track he produced using his ripple synth. Nils McKim, Scotland, produces some pretty dirty techno noise!

I hope he doesn’t mind me linking to his work, but I’m sure he’s available for weddings, christenings and the odd club night. It’s called Bang That Bitch. Any complaints regarding the name should not be directed at me…

Nice!

Msa midi kit

bod — Mon, 28 Dec 2009 19:03:09 +0000

Now that Christmas is over, I’ve had chance to build the kit I bought from highly liquid. I’ve had a few of these in the past, and they are really good quality and easy to build and use, highly recommend!

Took about an hour to build and about 15 minutes to install into my dr-110 to replace the arduino-midi converter I whipped up on strip board that was in there.

Op amp vco

bod — Mon, 28 Dec 2009 09:48:10 +0000

Well my triangle waves are nice and triangley…. How ever the square waves need a little work!

arduino and midi input

bod — Sun, 22 Feb 2009 12:21:51 +0000

i’ve been using the arduino for midi input and output for a while now, mainly using kuk’s input method, output is easy enough though. midi input had me stumped for a while, but he found adding 100k resistor to the base of the phototransistor of the optoisolator created a stable response which sorted it out.

theres alot you can do with variations of his code, and many people have used the circuit to build midi>cv convertors for analogue synths, but at the moment i’m mostly interested in building a clock source for analouge/digital sequencers so i can run them straight from the output of my HR-16 or tr-505 without the need for a computer based midi sequencer. the basic idea is to receive a midi clock byte and advance the count of a 4 bit binary output from the arduino to advance the steps of a multiplexer ic based sequencer.

midi clocks output 24 pulses per quarter note, so this needs dividing down to get the step response you need. the ever useful and highly inspiring code from littlescale comes in handy here!

more soon.

synth stuff

bod — Sun, 28 Dec 2008 01:39:36 +0000

i’ve been updating the synth pages with some schematics for cmos based noise boxes.

synth pages…>>>

PCB’S!! The Vidiot Pattern Synth V1.1

bod — Thu, 11 Dec 2008 10:27:51 +0000

Lots of lovely PCB’s for the pattern synth! (finally)

ROHS compliant and ready for building, hopefully at a workshop i have planned, and a few for sale as finished units and kits.

Squarewave Sequencer

bod — Sat, 02 Aug 2008 10:07:21 +0000

While trying to decide what to do with 10 of these 4052b demultiplexers I bought by mistake, I stumbled upon an interesting method of creating a squarewave step sequencer! Its perfect apart from the fact there are only 4 steps, but the method works, so 8 and 16 step versions should be no problem at all, even if it does involve a shed load of diodes…

The issue with these cmos oscillators is the fact they aren’t voltage controlled in the normal sense, so using the standard Baby10 style 4017 sequencer wasnt really an option, until now! So far I have a tempo control, four individual step pitch controls and a master tune control, all running off of 2 oscillators and a handful of components and IC’s.

I love these cmos IC’s, they are like Lego building blocks for noise!!!

Video to follow when i find the camera…..