1. POWER: flip switch up to turn preamp on (there’s a 2-3 minute “warm up” time for lowest distortion), flip switch down to turn preamp off
  2. MIC GAIN (stepped, 12-position switch): clockwise rotation yields an increase in input signal amplitude, counterclockwise rotation yields a decrease in input signal amplitude
  3. 48v: engage to turn phantom power on, disengage to turn phantom power off
  4. PHASE (Ø): engage to adjust input signal polarity by 180°, disengage to leave input signal polarity unchanged
  5. OUTPUT LEVEL: clockwise rotation yields less attenuation, counterclockwise rotation yields more attenuation (for beginners, it’s best to leave the output level fully clockwise and increase Mic Gain as needed so as not to saturate the input transformer)
  6. DI: engage to select front panel TS jack as input source, disengage to select rear panel XLR jack as input source


  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 BLA-specified power supply)

Black Lion Audio B173

£0.00 £475.00 inc. VAT
£395.83 exc. VAT

B173 Mic Pre

Introducing Black Lion Audio’s own 1073-style microphone preamp, the B173! Don’t let the price tag fool you. This is not only a serious contender for the most “bang for your buck” preamp in existence, but sonically stands on its own at any price point. Our goal was to capture the essence of the original 1073 at a price anyone can afford, and we’re proud to say that we’ve accomplished our goal! Tape Op gave it a run, and couldn’t agree more. Give the B173 a try and prepare to be blown away!

The B173 is Black Lion Audio’s homage to the highly revered 1073 mic pre. The B173 is a single channel mic preamp with input and output transformers, stepped gain, output level control, phantom power, and phase. It features a DI, 80dB of gain, and is housed in a 1U, 1/2 rack chassis.

  • Cinemag Input Transformer
  • Edcor Output Transformer
  • 80dB Gain
  • D.I. Input (active, unbalanced)
  • Phantom Power
  • Phase Switch
  • Output Attenuator
  • XLR Microphone Input
  • TRS Line Output (balanced)
Max Microphone Input Level
Input Impedance
Gain (no pad)
+13dB to +80dB
Equivalent Input Noise (noise floor)
THD+N (@ +4dBu output)
.10% @ +9 dBu .12% @ +35 dBu .13% @ +45 dBu .16% @ +60 dBu .85% @ +76 dBu
Bandwidth (1kHz, 150Ω source, unweighted)
10Hz to 30kHz
Max D.I. Input Level
Input Impedance
Up to +25dB of gain
Equivalent Input Noise (noise floor)
THD+N (@ +4dBu output)
.021% @ +10 dBu .016% @ +20 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

Download the B173 Manual