Coil Audio CA-286 MK1 Single Channel PS6 Modular Mic/Line Amp

The Coil Audio CA-286 is a two-stage amplifier based on circuits used by Langevin, Collins, Gates, and Telefunken during the 1950s and 60s. Each amplifier uses Coil's custom interchangeable transformers, NOS capacitors and resistors, and a pair of NOS EF86 vacuum tubes. With the addition of a flexible input pad network, the Negative Feedback tone shaping, and inter-stage volume control, the CA-286 is a timeless and flexible amplifier that compliments any microphone collection.

The PS-6 version is a fully removable module for use with the 6 channel PS-6 Rack Tray. Each amplifier is easily removable via two thumb screws for flexibility, expandability, and transformer substitution.

Controls:

• The (INPUT) pad section contains a phase reverse switch, and a 5 position attenuation network of Balanced H-pads. The first four positions are various 150/250 Ohm mic pads; -6 db, -12 db, and -19 db. The final (LN) position allows line-level signals to run through the amplifier providing tone-shaping capabilities while mixing. It works as both a second-stage booster for other preamps, and a summing/buss amp for program and mix material. Two amplifiers can also be chained together to create the multi-stage, high gain recording path of a vintage tube console.
• The NF, HI, and LOW controls all interact to create a unique tone-shaping circuit. The NF control varies the amount of Negative Feedback present in the circuit. Counter-clockwise brightens and moves the sound forward while raising harmonics and sensitivity. Turning it clockwise increases negative feedback, producing a darker tone with a smooth, dampened harmonic structure.
• The HI switch transitions from the natural openness of the tubes, to a gentle filtering of upper frequencies. The LOW switch reacts with the NF, boosting or cutting low frequency while moving the low end from front to back in the sound stage.
• The Output control knob is placed between the 1st and 2nd stage EF86 tubes. It sets the final level and offers further control of the two-stage gain structure.