Hi, The Beolab 4000 require a PowerLink Mk1 or Mk2 cable, while the Beolab 3 require a PowerLink Mk3 cable. This is due to the difference of power amplifier (IcePower Class D versus Call A/B). In the Powerlink MK3 cable, the Pin 7 must be connected to the ground. Here the Mk3 connection : Pin 1 - Not used Pin 2 - Audio Ground - Screen Pin 3 - Left Audio