Castanet Headphone Amplifier Kit Manual
6
3 Assembly
Chassis
Place the blank circuit board on the top panel, centered. Mark the center of the
tube socket. Drill hole in cover to 1.125” diameter using a step bit or hole punch.
Apply adhesive feet to bottom cover.
The extrusions come with their own mounting screws, but it works better if you can use a
#4-40 tap to pre-thread the grooves so you can use the #4 oval head screws provided.
Fabricate the front and back panels according to the drawings. Remove protective
plastic and wash with soap, water, and sponge. The stock panels can obtain a
really nice finish when cleaned. Or buy the pre-made panels from FPE.
Install the RCA jacks into back panel. Add short (about 2”) wires.
Install LEDs into front panel.
Circuit Board
Assemble in the following order, soldering and clipping leads as you go. Parts are
mounted on the side as shown by silkscreen. Refer to photos.
Install all fixed resistors (not volume pot). R5 and R6 are each made up of four 1-
ohm resistors in parallel. R9B is unused.
Install two rectifier diodes and one LED (not the LEDs on wires).
Install socket.
Install 1uF (4).
Install 470uF (2). Can be on either side of board. Beware of polarity.
Mount ac connector. Use two #6 screws, through the board, connector, thin
washers, and into the provided L-brackets. Solder in place.