Coil Audio CA-286S — Single-Channel Tube Microphone Preamplifier

The Coil Audio CA-286S is a standalone, single-channel 2U tube preamplifier built around the same European-style circuit, transformers, and high-end components found in the larger CA-286 PS6 preamp module—with onboard power and a more streamlined control layout. At its core is a two-stage dual EF86/6267 vacuum tube circuit, delivering the warmth and high-fidelity character that has made the EF86 a studio staple for decades. CT-110HN input and CT-41 output transformers anchor the signal path alongside NOS tubes, PEC carbon pots, and selected signal caps and resistors. The CA-286S is hand-built and tested in the USA.

Key Features

• Two-stage dual EF86/6267 vacuum tube circuit with 42dB–60dB of available gain
• CT-110HN input transformer and CT-41 output transformer
• Negative feedback tone adjustment with LOW filter
• Flexible input pad section for mic or line level operation (150Ω mic input, 20kΩ line input, 600Ω output)
• NOS tubes, signal caps and resistors, PEC 2W carbon pots throughout
• Slow-ramping, linear-regulated power supply to prolong tube life
• 2U all-steel enclosure with integrated power supply
• Hand-built and tested in the USA

Specifications

• Form Factor: 2U rackmount
• Channels: 1
• Tubes: Dual EF86/6267 (NOS)
• Input Transformers: CT-110HN
• Output Transformer: CT-41
• Gain Range: 42dB–60dB
• Mic Input Impedance: 150Ω
• Line Input Impedance: 20kΩ
• Output Impedance: 600Ω
• Power Supply: Integrated, slow-ramping linear regulated
• Construction: Hand-built and tested in the USA