1. POWER: flip switch up to turn preamp on, flip switch down to turn preamp off
  2. 48V: engage to turn phantom power on, disengage to turn phantom power off
  3. PHASE: engage to adjust input signal polarity by 180°, disengage to leave input signal polarity unchanged
  4. PAD: engage to reduce input signal amplitude by 18dB, disengage to leave input signal amplitude unchanged
  5. GAIN: clockwise rotation yields an increase in output signal amplitude, counterclockwise rotation yields a decrease in output signal amplitude
  6. Hi-Z: engage to use front panel Hi-Z IN as preamp source, disengage to use XLR input as preamp source
  7. Hi-Z IN: input jack for use with high impedance, unbalanced sources (GAIN knob adjusts signal amplitude)


  1. OUTPUT: balanced, line-level TRS output
  2. INPUT: balanced, mic-level XLR input
  3. GND: internal chassis ground
  4. POWER: 24VAC input jack (only use a B.L.A.-specified power supply)

Black Lion Audio B12A MK2

£0.00 £425.00 inc. VAT
£354.17 exc. VAT

B12A MKII Mic Pre

What happens when you take the stately B12A and add some extra special sauce? You get the B12A MKII! With a titillating Cinemag input transformer, less noise, and more API®-style gain than ever before, the B12A MKII will sweeten your preamp collection for years to come! According to Phil O’Keefe at Harmony Central, “Black Lion Audio’s B12A MKII is one of the best ways to get into a 312A style preamp at a reasonable price,” (full review here). Get ready to hear what you’ve been missing!

Inspired by the classic American rock sound of the original API® 312A, the B12A MKII delivers the high-end sound and rugged quality you’d expect from B.L.A., at an amazing price! The B12A MKII is a single-channel microphone preamp in the style of an API® 312A, and features an upgraded input transformer, higher gain, and lower noise than the original B12A. It also features an output transformer, a Hi-Z input, phantom power, pad, phase, and is housed in a 1U, 1/2 rack chassis.

  • Cinemag Input Transformer
  • Edcor Output Transformer
  • 70dB Gain
  • Hi-Z Input (passive, unbalanced)
  • Phantom Power
  • 18dB Pad
  • Phase Switch
  • XLR Microphone Input
  • TRS Line Output (balanced)
Max Microphone Input Leve
Input Impedance
Gain (no pad)
+26dB to +70dB
Equivalent Input Noise (noise floor)
THD+N (@ +4dBu output)
.012% @ +22 dBu .013% @ +36 dBu .046% @ +56 dBu .145% @ +66 dBu
Bandwidth (1kHz, 150Ω source, unweighted)
10Hz to 30kHz
Max D.I. Input Level
Input Impedance
+10dB to +53dB
Equivalent Input Noise (noise floor)
THD+N (@ +4dBu output)
.013% @ +10 dBu .124% @ +36 dBu
Bandwidth (1kHz, 600Ω unbalanced source, unweighted)
10Hz to 30kHz
Max Output Level
Output Impedance
Power Supply
24VAC, 500mA External Supply
Product Dimensions
9.5” x 6.5” x 1.75”
Product Weight
3.2 lbs
Shipping Dimensions
13” x 13” x 5”
Shipping Weight
6 lbs