Analog Modular Synthesizer
The POG1 is my second homebuilt modular analog synthesizer. At this point it is on it's fifth version having had many transmutations over the years. It was first built in 1992 with a very hack-mangled Realistic MG1 as the main sound generating module and a few control signal generating modules added. 8 years later i finally removed the MG1 and used modules from my first homebuilt (the POS) to replace it.
DUAL VCO and Interface Module (3&4) -based on the Moog Rogue circuit
DUAL LFO (CO3&4)
DUAL ADSR ENV GEN (1&2) -based on the Electronotes circuit (CD4053)
DUAL VCO and Interface Module (1&2) -uses a CEM 3374 dual VCO, CEM
3372 dual VCF & VCA and a
VCLFO of my own design (kinda, sorta) this combo has a very clean, almost thin sound, quite different from VCO 3&4 which is quite thick, raspy, and 'fat'
VOLTAGE MODULE (1) -a module of simple utility circuits; 1 adjustable voltage, inverters, an attenuator, a voltage comparator, and the one unusual feature- a dual random voltage generator. one RVG is a noise filtered by a 4p adjustable frequency (but not voltage controlled)LP filter. the other RVG is a noise source through 1p LP fixed filter and a very high Q (adjustable)(one op amp, slightly unstable it seems) 1p BP filter that gives an output adjustable between total noise and oscillation at the frequency of the filter, which is about 6hz. this circuit is from Electronotes Prefered Circuits Collection.
VOLTAGE WHEEL MODULE (2) - circuitry for the voltage wheel and pushbutton trigger, plus two adjustable voltages, inverters, a comparator,and two attenuators.
FLYING SAUCER INTERFACE MODULE (Shadow Controller)info here
DUAL VOLTAGE CONTROLLED ENV GEN (5&6) -based on the SSM2056 IC
10 STEP SEQUENCER - a very basic dual channel 10 or less step sequencer with trim pots for voltage settings (ok laugh all you want, i was on a budget)
DUAL ADSR ENV GEN (3&4) -Electronotes style
DUAL LFO (2&3) -based on a pair of ICL8038 ICs, not quite ideal (limited VC range, sloppy waveforms at lowest rate) but they work ok.
NOISE VOICE (Noise,VCF,VCA,LFO) -was part of a drum synthesizer/drum machine from quite way back in my engineering day (around 1986.) the noise source is the regular old reverse bias transistor, plus a 4P LP VCF made with an MF10 switched capacitor filter, the VCA is a simple linear CV CA3080 circuit. also included is a VCLFO and a manual control 2P HP filter which uses a dual gang potentiometer. it can select inputs between the on-board noise source or an external signal.
RESONATOR (with VCF,VCA) - the Resonator section of this module was inspired by a post to synth-diy by Paul Harding with a link to an article in Sound on Sound magazine about a guy named Ron Berry about doing physical modeling with analog synthesizers. basically it is an old analog delay pedal that i modified adding a mixer on the input, a mixer on the output, and VC delay time. the VCF/VCA portion is based on the SSM2045 and i quite like it.
MIXER/OUTPUT - a simple (read:cheap) 6in 2out mixer with VCAs and a LFO for auto-panning
Joystick and Interface Module - i totally cracked the wallet and spent
a dollar at a garage sale for an old Tandy joystick
looking at the back of the POG1
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