Originally Posted by markg
Scenario 1: The headphone amp also had plugged into another one of its input, the analogue outputs from my Digital TV set top box (e.g. like a Sky HD / cable box).
Try this scenario again, but unplug your antenna cable from the set top box.

HD621, G98DH, G68ADV, Bc Acoustiqe ACT A3, 5200C DSP33, NuForce Reference 9 monoblocks, 2x SB3's, Velodyne DD-15 & DD-12 Subwoofers and a Meridian sub.