Hi Leo,
Just wondered if you have got any further? I am probably going to ask Tirna (who do the 4032=capacitor upgrade for the 7520) to quote for doing some of the mods you suggest to my SB3 but only in the digital domain and nothing that involves loosing wireless reception.
Jerry
Hifi: IPL transmission line floorstanding speakers, Squeezebox Touch, Denafrips Ares 11 DAC, DCB1 Pre-amplifier, Croft Series 7 power amp.
Custom Hifi cables HA10SE headphone amplifier and Hifiman HE-400 headphones.
AV system: LG 55B7, Denon AVR -x2300w receiver, Quad 12L (front) 11c Centre and 11L rear . Velodyne DD15 subwoofer.