My Linn Klimax DS streamer had ferrite ring inside the power supply -- right between the IEC socket and input transformer.
I opened the lid and removed it and this made a noticeable improvement in SQ, especially in bass section.
I agree that these things can suppress RFI contamination, but it looks like it comes at cost of the transient performance.
It's better to clime one step up in Naims PS range.
I believe Naim PSs address RFI in their own way and without detrimental effects on the speed and I better feed Naim gears straight from the wall outlet -- better with dedicated line directly from the house main switch.
