Got hold of a Linear PSU for the laptop. Zero-Zone L164-30, Ultra Low Noise. This does 'seem' to affect the perceptible audio sound. Not only does it sound sharper and clearer, but also seems to alter the 3D spaciality: makes wider & deeper but also tighter at the same time.
ARCAM FMJ-A19 + Tacima CS947, Tannoy DC6T Speakers, Tannoy TS10 Subwoofer + Tacima CS947, Sennheiser HD 558 headset, Arcam Miniblink DAC + iFI iPOWER, HP Pavilion G6* - 2382sa D0Y14EA#ABU + Creative BT-D1 [+ Azio BTD-V401]; [*using onboard battery for music listening]. + Audio Software [Room EQ Wizard, Equalizer APO, media players]. I also have a Creative Cambridge DTT2200 5.1 System, & Denon AH-D320 Phones.