50% volume + video related input noise

[junglechris]

Hi guys, Ive previously made a post about blowing up my TA2020 chip but previous to explosion i had noticed sound audio anomalies that i was hoping someone could help with.
With volume over 50% i noticed a faint high frequency noise from the speaker. This was with no audio playing, instead simply just connected up to all devices.
Increasing the volume made the noise more audiable.

Isolated tests; I tried to identify where or what was causing the noise. With the speakers pluged in and the amp on with volume 50% to 100% quiet and a button. No noise.
Plugging in the video input cable once again produced no noise.
However plugging into any device like a game console audio, mp3 player, laptop.. The noise made itself apparent.
Im aware that the signal device will produce at full volume a very small about of noise BUT i found no variation in noise volume when altering the signal devices power volume output.
So all this testing led me to rule out the input devices.. The amplification process## NOTE HOW I DIDNT RULE THE AMP ITSELF###

It seems to be the conection between the two devices or something just after inside the amp.

Im no expert and I dont mind being schooled because its all about learning so all suggestions are welcome.