Locomotive Audio Model 86B-2

Locomotive Audio Model 86B-2 is a two-channel tube mic/line preamp in its own 2U rack chassis, a modernized take on the preamp from the mid-1950s Ampex 601 suitcase tape recorder. Each of its two channels is an independent circuit built on an EF86 input tube and a 12AY7 output tube, delivering up to 75dB of gain. It's the two-channel counterpart to the single-channel 86B-1 module from the same Locomotive preamp family.

Two full channels, not one preamp with a splitter

The 86B-2 succeeds Locomotive's earlier 286A from 2014, adding separate mic and line XLR inputs per channel plus a higher-impedance DI than its predecessor. MuMetal-shielded input transformers and nickel-and-steel output transformers, both wound in-house, finish the signal path ahead of the output XLR.

Control at every stage of the signal

Each channel has a switchable mic input impedance (500Ω or 1.8kΩ), a -20dB pad, a 100Hz high-pass filter, 48V phantom power with a polarity switch, and a 3-colour LED output meter (green above -10dBu, orange above +10dBu, red above +18dBu) for a quick level check without looking at the DAW. Two independent channels in one chassis make it easier to track stereo pairs, drum overheads or a vocal duet, without linking two separate units with a stereo-link cable.

KEY FEATURES

• 2-channel tube mic/line/DI preamp
• EF86 (input) and 12AY7 (output) tubes per channel
• Modernized Ampex 601 design, successor to the 286A
• Switchable mic input impedance: 500Ω / 1.8kΩ
• -20dB pad and 100Hz high-pass filter
• 48V phantom power with polarity switch
• 3-colour LED output meter
• Hand-built in the USA

TECHNICAL SPECIFICATIONS

• Type: 2-channel tube preamp
• Tubes: EF86 + 12AY7 per channel
• Maximum gain: 75dB
• Frequency response: 20Hz – 20kHz
• Maximum output level: +24dBu
• Impedance: line input 10kΩ, DI 1.6MΩ, output 300Ω
• THD+N: <1%, S/N: >70dB
• Dimensions: 482 x 89 x 254mm (2U)
• Power: 25W, 115/230V AC