Keywords: Vactrol Inverse law VCA (split grounds).PNG Vactrol-based remote-controlled variable gain amplifier with an inverse control law V out V in / V c / Vref Based on PerkinElmer 2001 http //www datasheetcatalog org/datasheet/perkinelmer/VT500 pdf Photoconductive Cells and Analog Optoisolators Vactrols® page 66 I regrouped the components to show split audio and control grounds own 2010-11 East of Borschov <span class signature-talk >talk</span> 09 00 16 November 2010 UTC Drawn in Proteus v 4 underlying schematic is PD Vactrol |