Voltage Controlled Amplifier

This very simple VCA is based on the one I used in my US1 modular. It has proven to be very efficient. At first glance it looks like a classical cascode circuit, but the current sink (Q3) is not mounted in series with the emitters of the differential pair Q1-Q2.
The current draw of this module is quite low : 5mA from the +15V rail and 4mA from the -15V rail.

http://www.yusynth.net/Modular/EN/VCA/index.html