Wednesday, 9 March 2011

Video VCA and mixer by Tom Gamble of EFM

Heres a damn fine module, that i had no part in designing. its an EFM module, designed by Tom Gamble back in 1999. i was lucky enough to buy a load of his PCBs back then and have enjoyed building them, making music with them and endlessly tweaking them ever since.

low res schematic. download the proper PDF below:

anyways, back to the plot.. this is an excellent audio modular synth circuit, its the VCA5B design from toms 1900 series modules. it works very well and in exactly the same way as with audio at video frequencies too. i have no technical specs to back this up, but it works for me..... its also where i borrowed the design for the attenuverting inputs in my synth- its the same circuit but every 47k resistor or pot has been exchanged with 100k because i happened to get a good surplus deal on hundreds of 100k pots. guess what part most of my designs will be featuring for the forseeable future...
the PDF is here
the various corrections from the old EFM forum are here
and both of the above are linked to from this excellent site, which i have mentioned before. go there and read. then go build stuff.
be seeing you

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