Camille Cascode Constant Current Source
C4S is a high impedance current limit circuit for preamp and driver tubes, designed by John Camille. It includes two PNP transistors and two LEDs per tiny PC board (2 boards are provided in the kit for a stereo pair) and an extensive 28 page manual written by "Buddha" Camille himself. This current source may be used as a plate or collector load for voltage differentials up to 300 volts. Use of NPN transistors will allow use if the board as a current sink for cathode loads in cathode follower and differential circuit applications. The circuit current and bias are easily adjusted with just two resistors. The C4S circuit boards are designed for easy series and parallel resistor configurations, for precise matching. What does all this mean? The 5 megohm effective impedance characteristic of these active loads permit near theoretical gain performance from voltage amplifier stages, and can reduce distortion in vacuum tube audio circuits by several hundred percent. Noise generated in this circuit is up to 40 times less than several commonly used circuits. The result is clarity, bass speed and drive that beats resistive loads, choke loads, and other tube and solid state loading schemes like mu followers/stages and SRPPís. For applications, check out John Tuckerís "Single Ended Direct Coupled Active Loaded Parallel Feed 45" in the October 1997 VALVE, as well as Docís Blues Master VV32 amp and Soul Sister preamp in 1998ís VALVE issues. A pair of C4S boards is also used in our Afterglow and Paraglow 2A3 SE amplifier kits, and four C4S boards are used in our Anticipation upgrade to the Foreplay preamp. The detailed manual shows you how to easily adapt the kit to most conventional preamp and driver stages.
C4S Kit PC boards for two channels, transistors, LEDs and 28 page manual - $35