Coil Audio CA-70 MK2

Coil Audio CA-70 MK2 is a modular mic/line tube preamp that recreates the classic American two-stage circuit built around 6J7/6C5 tubes, the topology used by Western Electric, RCA, Gates, and Langevin through the 1950s. The module mounts in the PS6 rack, sharing power with other CA-series preamps.

American character on NOS tubes

The circuit runs on NOS (New Old Stock) tubes, so the sound matches original mid-century units rather than a digital emulation of them. A 42-54dB gain range covers most mic and line sources, and tone shaping runs through a negative-feedback circuit with high- and low-pass filters, an unusual feature for a tube preamp in this class, which typically ships with no onboard tone control at all.

Swappable transformers instead of one fixed sound

Inputs and outputs support interchangeable/optional transformers, so the preamp's character can be tailored to a specific use instead of being locked to one factory configuration. Input impedances (150 ohm mic, 20k ohm line) and output impedance (600 ohm) are standard studio values, and Neutrik XLR plus military-grade Cinch Jones connectors keep the connection to the rest of the chain solid.

KEY FEATURES

• Two-stage 6J7/6C5 tube circuit, American console heritage
• NOS (New Old Stock) tubes
• 42-54dB of gain
• Tone shaping via negative feedback, HP/LP filters
• Interchangeable/optional input and output transformers
• Neutrik XLR and military-grade Cinch Jones connectors
• Modular mounting in the PS6 rack

TECHNICAL SPECIFICATIONS

• Circuit type: two-stage tube, 6J7/6C5
• Gain: 42-54dB
• Mic input impedance: 150 ohm
• Line input impedance: 20k ohm
• Output impedance: 600 ohm
• Connectors: Neutrik XLR, Cinch Jones (military grade)
• Format: PS6 rack module (up to 6 modules)