This is just demo testing the second synthesizer i built for someone ,it contains a doepfer pcb board ,additional MFOS VCO ,Yusynth Sample and Hold ,MFOS Noise ,Suboctave ,MS20 XOR ,Glitchy Steiner VCF (my first proper pcb i built) ,Analog Neuron , the little black/white box is an external PSU with +/- 15 V ,+/- 12 V ,9V / Ground ,all could have been done better):

Few patches on the modular synthesizer ,these contain 2 VCO's ,some patches only one ,parts of buchla SOU ,one VCS ,SEM and Polivoks VCF .

https://archive.org/details/Synthacks-Vlad-Scetchbook

Drum Oscillators - Onda Quadra 1979_01

 

 Berry Klein - Electronic Muisc Circuits

 

 

 

Tektronix CFG250 Function Generator 

Tektronix FG503 Function Generator

Polyphony Magazine - Random Tone Generator ; Freq. Divider .
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 VCF - D.Avramov ; V Veleva

Nueva generacion instrumentos electronicos - Juan Bermudez

 

 

 

Emu UAF ( Universal Active Filter )

designs by Sergio Franco (Sal-Mar Construction)

 

 

 

Psychoacoustic Enhancer article by Paul Williams HSR August 1985

 

 

VCO by Stephan Winter ,full pdf with double sided pcb layouts for vco ,vcf ,envelope ,lfo etc. :  http://www.uni-muenster.de/imperia/md/content/fachbereich_physik/technik_didaktik/entwicklung_bau_synthesizer.pdf

Mixer , headphone and tone controls from November issue of Onda Quadra ,designs by A. Lazzari ,Riccardo Monti