Check out the Grand Modular page, I’ve added a lot of control overveiw and information.
This is a demo of the sequencer section of the Grand Modular Synth MK1, technically this is the Octaviatron MK2.
First I demo the gate output length control; this is used to gate an envelope which is used to control the VCF into which one square wave VCO is connected.
Changing the gate length is like changing the amount of time you hold a key down on a keyboard, hold it for longer and the envelope attack will rise more, for less and you get a punchier sound when used with a fast attack envelope.
Next I demonstrate the pause and reset functions.
Later in the demo I turn switch the speed to audio frequency and use that as a control voltage for some really spacey sounds (at about 2 mins 30 secs).
At about 5 mins I take the output directly from the sequencer, using it as a waveform generator however for a few seconds I can’t figure out why the signal was so low but it was because I left the slew turned on (which is basically a low pass filter) so when operated at audio frequencies, the signal is filtered down a lot.
This is one of my sound machines, built a few months ago now but the idea behind it is so adaptable that I’m constantly developing it … do I even have shcematics for this!?
Just checked my files and yes I do! In the form of hastily scribbled incoherant notes :D
The core of this device is a 4089 frequency “multiplier” chip, which acctually divides the frequency weirdly- as I’m quite aware, that is just code for: Brilliant sound manipulator!
This archaic chip outputs anywhere between 0 and 15 pulses every 16 clock cycles, the number of pulses determined by 4bit binary numbers between 0 (0000) and 15 (1111).
Use the strobe input to control both the output and output-bar, and the cascade input is OR’ed with the output-bar.
Want one of your own? Then roll up ladies and gents and bid on the auction! http://www.ebay.co.uk/itm/8159R-Sequencer-Rhythm-Generator-homemade-vintage-junk-synth-synthesizer-/150778158205