TK Audio BC501-Ltd


TK Audio BC501-LTD

Smooth transparent glue.

  • Sidechain filter with three frequencies.
  • Selectable THD function for more “even” harmonics.
  • Grab function that selects a harder threshold knee.
  • Blend control for easy parallel compression.
  • All controls stepped for easy recall.

TK Audio’s best-selling 500-series module, the BC501, is a stereo bus compressor that features all the power of TK Audio’s flagship BC1-THD. Since its release in 2015, it has found its way into a great number of 500 racks all around the globe. The BC501 is one of the most transparent stereo bus compressors ever made. The smooth, soft compression together with the blend control, high-pass filter, and the THD function are much-appreciated features that now have been expanded with the grab function, known from the BC1-THD. The grab function turns the threshold knee harder and makes the compressor even more perfect for the drum-bus. The BC501 is available in two versions, the BC501-GR with the standard stock black panel and the BC501-Ltd with a silver panel, individually numbered and limited edition of 100 units.

  • Power requirement: +110mA / -90mA (total)
  • Frequency response: 20Hz to 20kHz +/-0dB
  • Frequency response: 20Hz to 80kHz +0dB/-0.1dB
  • THD+N @ 1kHz: less than 0.005%
  • Signal to noise ratio: 95dB
  • Cross talk: -90dB
  • Input impedance: 24kohm
  • Output impedance: 50ohm
  • Max input level: +26dBu
  • Max output level: +27dBu

BC501 Version History

  • BC501. Released April 2015
  • BC501-GR / BC501-Ltd. Grab function added and an individually numbered limited version released. (released April 2021)


  • Threshold: -20dB to +20dB in 41 steps
  • Make-up: 0 to +20dB in 41 steps
  • Ratio: 1:25, 1.5:1, 2:1, 4:1, 6:1, 10:1
  • Attack: 0.1, 0.3, 0.6, 1, 3, 6, 10, 30, 60, 120mS
  • Release: 50, 100, 300, 600mS, 1.2S and Auto (50mS/2S)
  • HP Filter: 80Hz, 150Hz and 220Hz (-6dB/octave)
  • External sidechain input via a stereo 3.5mm TRS
  • THD circuit that adds even harmonics
  • Blend control from dry to compressed in 21 steps

Specifications and components may be changed or updated without further notice.