A-101-6

A-101-6 is a new filter module that uses so-called opto FETs to control the filter frequency. Opto FETs are very similar to Vactrols but use light depending field effect transistors (FETs) instead of light depending resistors (LDRs). A opto FET is a combination of a light depending FET and a LED (light emitting diode) both put into a small light-proof case. The advantage compared to vactrols is the much faster response of opto FETs compared to LDRs. This allows much faster attack/decay times and even FM effects. The disadvantage compared to vactrols is that the FET behaves as a normal Ohm resistor only for small levels. With higher levels the FET begins to distort. Apart from this the notes mentioned on the Vactrol Basics page are valid.

• Width: 8HP
• Depth: 40.3mm
• Current draw: +12V : 40mA ; -12V : 40mA

http://www.doepfer.de/a1016.htm