Thermionic Culture Earlybird 2.3 2-Channel Valve Mic Preamp with EQ

The Thermionic Culture Earlybird 2.3 is a 2-channel valve mic preamp with 3-band active lift EQ, built around a push-pull Class A amplification circuit that delivers clean, low-noise, low-distortion gain. Sowter input and output transformers—designed in collaboration with Sowter specifically for this unit—provide the lowest possible phase shift and highest headroom available from a mic preamp. The active EQ operates in the feedback path of the circuit, meaning switching it in introduces no additional gain stages to the signal path; EQ can be applied without risk of added artifacts from extra active stages. A Function switch allows the unit to accept mic, line, or Pullet passive EQ signals from the rear panel without re-patching, making the Earlybird 2.3 a versatile option for tracking, mixing, and mastering applications.

Key Features

• Push-pull Class A valve amplification — 2 channels of clean valve gain with the lowest noise and distortion figures achievable in a mic preamp; controls for gain, impedance, 48V phantom, and phase per channel
• Sowter input and output transformers — custom-designed in collaboration with Sowter for the Earlybird 2.3; provides minimum phase shift and maximum headroom
• 3-band active lift EQ (feedback path) — EQ operates in the feedback section of the circuit; switching it in adds no extra gain stages, allowing subtle EQ to be applied without signal degradation
• Bass and top lift — varislope curves — Thermionic Culture’s unique varislope design; as the control increases, the peak frequency becomes progressively more extreme, adding heavier bass or brilliant top without the hardness of solid-state EQ
• Mid lift — switchable frequency — broad, musical bell curve centered at 800Hz or 2.8kHz (frequency select switch); interacts with bass and top controls for wide tonal shaping possibilities
• High pass filter — 12dB/oct at 40Hz or 100Hz; third position provides a shelving-style curve that can be combined with the bass lift control for a simultaneous mid cut and bass lift effect
• Function switch — selects input from Mic In XLR, Line In, or Pullet sockets; variable impedance and pad settings on the switch allow the input circuit to be optimized for a wide range of mics and signal levels
• VU meters — signal level monitoring per channel
• Handcrafted in England

Specifications

• Channels: 2
• Amplification: Push-pull Class A valve
• Transformers: Sowter (custom; input and output)
• EQ Type: Active lift (feedback path); 3-band
• EQ Bands: Bass lift (varislope); Mid lift (800Hz / 2.8kHz switchable bell); Top lift (varislope)
• HPF: 12dB/oct at 40Hz or 100Hz; shelving mode (3rd position)
• Input Sources: Mic In XLR, Line In, Pullet (via Function switch)
• Phantom Power: +48V (per channel)
• Metering: VU meters
• Construction: Handcrafted in England