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CA-286 Modular Mic/Line amplifer

The 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 our own custom interchangeable transformers, NOS capacitors and resistors, and a pair of NOS EF86 vacuum tubes. With the addition of a flexible input pad network, our Negative Feedback tone shaping, and inter-stage volume control, the CA-286 is a timeless and flexible amplifier that compliments any microphone collection.

CA-286 Amplifier FEATURES:

  • Two-stage EF86/6267 pentode vacuum tube-based circuit
  • 42db-60db of available gain
  • Flexible input pad section for mic or line level operation
  • Transformer balanced. 150 Ohm or 10k input, 600 Ohm output
  • Interchangeable/Optional input and output transformers
  • NOS tubes, signal caps & resistors, PEC 2W carbon pots
  • Up to Six CA Series Amplifiers mount into our PS6 Rack
  • Up to Two Amplifiers in our PS2 Rack
  • Hand Built and Tested in the USA

Two Different Chassis Versions are Available

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

The PS-2 version comes factory installed in our PS-2 Rack and PSU. This combines the power supply and modules into a single 3U case creating a compact 2-channel modular solution. The amplifier and power supply are otherwise identical to our larger PS-6 versions.

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THE 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; -6db, -12db, and -19db. 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.