Coil Audio 2 x CA-70 modules with PS6 rack

The Coil Audio CA‑70 modular tube mic/line amplifier with PS6 rack‑mount power supply delivers a thick vintage‑tube tone through a two‑stage 6J7/6C5 circuit, offering 42‑54 dB gain, selectable input pads for mic or line levels, 150 Ω mic and 20 kΩ line inputs, 600 Ω output, interchangeable transformers, and a dedicated PS6 chassis that supplies regulated 6.3 V filament and 275 V B⁺ power to up to six modules, complete with soft‑start, independent filament/B⁺ switching and rugged Cinch‑Jones/Neutrik XLR connections.

Classic Design Meets Modern Enhancements

The CA‑70 honours the 1913 Western Electric two‑stage topology while integrating modern components such as NOS octal tubes, high‑quality capacitors, PEC 2 W carbon pots and custom‑wound transformers. Negative‑feedback control lets users brighten or darken the sound, and paired High/Low switches provide gentle top‑end filtering and low‑frequency boost or cut. The PS6 rack supplies clean, point‑to‑point wiring, military‑grade connectors and a 5‑ft umbilical power cord, ensuring stable operation for multiple modules in a compact 7U chassis.

Feature Overview

The amplifier presents Input and Output gain knobs, a phase‑reverse switch and a dedicated Negative‑Feedback knob that shapes tonal character. The Low switch works with Negative Feedback to adjust bass response, while the Hi switch attenuates treble. Each stage employs a CJ7 and 6C5 tube, with an output control situated between them for fine‑tuned level management. The PS6’s soft‑start protects filaments, and its switched filament regulation allows separate powering of modules 1‑3 or 4‑6, with fault‑indicating fuse holders for safety.

Why Choose the Coil Audio CA‑70 & PS6?

• Authentic vintage sound – classic two‑stage tube circuitry reproduces the warm, musical character of historic Western Electric designs.
• Modern reliability – hand‑built in the USA with point‑to‑point wiring, robust military‑grade connectors and regulated power supplies.
• Flexible gain structure – 42‑54 dB of gain, selectable mic/line pads and independent input/output controls suit a wide range of studio applications.
• Tone‑shaping versatility – negative‑feedback, High/Low switches and phase reversal give precise control over brightness, warmth and stereo imaging.
• Scalable rack solution – the PS6 accommodates up to six CA‑70 modules, providing clean power distribution and easy integration into existing rack systems.

• Two‑stage 6J7/6C5 vacuum‑tube circuit delivering 42‑54 dB gain
• Negative‑feedback tone control with High/Low frequency filters
• Input pad selectable for mic (150 Ω) or line (20 kΩ) levels
• 600 Ω output impedance with interchangeable input/output transformers
• NOS octal tubes, premium capacitors, PEC 2 W carbon potentiometers
• Independent filament (6.3 V @ 4 A) and regulated B⁺ (275 V @ 0.5 A) supplies
• Soft‑start and standby functions on the PS6 rack unit
• Switchable filament power for modules 1‑3 or 4‑6
• Rugged Cinch‑Jones and Neutrik XLR connectors, 5‑ft military‑grade power cord
• Hand‑built and tested in the USA, point‑to‑point wiring throughout

This item, like everything we supply, comes with the complete support of our expert team. Our excellent technicians have been specifying, building and supporting studios for over twenty years. If you have any problems with installation, setup or everyday use, they’re never more than a click away, and always happy to help.

You can contact them here.