Yes I can believe that

Plus a Missing Link socket ?

And there are those that say mains doesn't make any difference.
Only enough to take the breath away

I noticed last night that with 10 plug-in filters cleaning my mains, a PS Audio Harvester that I placed in the kitchen so that I can see it was still flashing its LED about once per second, indicating that noise was still being cleaned.  You can't have too many mains filters!

Yes they are filters, otherwise they wouldn't do anything. Do you have the stand-alone plug-in type or built into a distribution strip/block?

Good. Spread them around the ring main powering the hi-fi system.

I have one more PS Audio Harvester coming from eBay USA as it looks like they've been discontinued. I put them where I can see them as they are such a useful indicator of noise. On most evenings they remain dark; on some, they flash continuously indicating a lot of noise coming into the house.



I also upgraded my PC recently to a NUC-style Gigabyte BRIX and took the opportunity to re-route everything PC based through my APC UPS.  Since all the accessories use plug-style SMPS, which are horribly noisy, I snap-choked them all to death (using TDK snap-chokes in various sizes) and put a couple on the master feed to the UPS, with the Kemp SNS-PLUG next to it.  That should take care of that!

Those cable ferrites are very cheap in comparison with all the other stuff you use Martin and as such I think anyone could usefully try them and sell them on if the 'effect' was inaudible or not as required.

Another silly anecdote... I've owned for twenty two (EEK!!) years, a Micro Seiki CD-M2 CD player, which is the same heavy cast chassis as the Marantz CD94, but with a second analogue board (with earthing and wiring alterations on the main board to accommodate it) offering balanced outputs (same chips but film caps as well as balanced output transformers). The original analogue outputs are still there via posh looking phono sockets on the back panel. Micro Seiki supplied a set of XLR to Phono cables and using these from the transformer coupled XLR outputs gives a much better 3-D sound output usually, than the slightly 'closed in' sound via the phono sockets. My first experience of using clip-on ferrites was on a 'Chord Solid' interconnect from the phono outputs, both into my AVI S2000MP+P preamp, which had a useful bandwidth out to 300k or so.

Cutting this long tale short, the 'Solid' interconnects on their own from the standard output, weren't as good as the supplied XLR to phono M-S cables, but with a ferrite clipped on each one, the friend who showed me and I, thought the differences far less between them. The conclusion was that the output transformers were filtering off any nasties in the audio feed - that TDA1541 based chip-set may be revered today, but they're bloody noisy in a high-frequency electrical sense I believe - mains too. needless to say I still use the Roxburgh 6A mains filters I bought years ago on my digital sources and really ought to use one on the workroom PC as it's on all day usually and used as a music source....

I bought from here and the duty/VAT are inclusive.

I am more than ever convinced that killing noise to benefit your system's sound quality is a holistic whole-house exercise.  You need to kill it in a distributed way, and at source (e.g. around PCs) and into your system itself.  I have a wonderfully low noise floor which at night allows me to peer deep into a recording.  It's taken some time to get here.