Ferrite clamps - good or bad?

[Marco]

What's the consensus of opinion on their efficacy or otherwise?

Due to a suggestion from a friend I decided to revisit the old ferrite clamp thing (which I hadn't experimented with in years) and attached ones to various cables throughout my system, both signal and power-carrying, with pretty good results. Due to past experiences I had been very sceptical beforehand whether they would work or not.

There is a noticeable reduction in background noise and 'hash', creating a 'blacker silence' from which the music to emerge. It's interesting as I didn't like their effect in a Naim system some years ago but in my current valve-based set-up the effect is positive resulting in a marked improvement in sound quality. I currently do not use any other filters on cables in my system, passively, or actively at source via a mains filter (although this will change shortly with the addition of dual TD mains filters for both the analogue and digital sections of my system), although I do have a separate mains spur.

Any theories as to why they're effective now but weren't before? Also, what exactly are ferrite clamps designed to do in a technical sense?

Cheers!

Marco.

[Mike]

My advice would be: live with them on for a while then take them off again.

I've mucked about with them loads!... They can have strange effects sometimes. I've found that what seems like a reduction in noise can turn out to actually be a roll off of high frequencies. This is when fitted to interconnects.

I've found I got more benefit fitting them to mains cables. In particular, the power cables that have nothing to do with the HiFi system! They're all over the place here, telly, PC equipment, fridge/freezer, heating system etc etc... seems to keep noise out of the mains system or something. At least that's my half baked theory!

Take them off again after a week or so and see what you think then.

I've noticed from pictures that Neil seems to use them extensively, maybe he could add his opinion?... I've been meaning to ask him actually.

[Marco]

I'll defo leave them on for a bit and assess them again later

Do you know, technically, what exactly they're supposed to do?

Marco.

[Mike]

Basically nothing at audio frequency, they're used to attenuate radio frequencies. The kit we use at work is dripping with the things!

http://www.gbrcaa.org/ntoa/Filters,%...0and%20OIs.htm

http://news.bbc.co.uk/2/hi/health/4203077.stm

http://www.topmagnetics.com/pdf/guid...OfFerrites.pdf

[Spectral Morn]

Hi Mike and Marco

Well I have been using them for 20 years plus and the reason is that they combat Radio Frequency pollution. This can be external i.e environmental or come from items in your set up, especially digital items (CD, Dac, Dab,PC etc) or those which use switch mode psu (these are dirty we sods).

I find that what Marco says is the main area of improvement, but I would have to accept that perhaps what Mike says could also be the case. Though I have never felt this to be the case in my systems.

I have ferrite clamps on most things. Speaker cable, Interconnects between pre and power, cd player and a fair number on cables associated with the turntable phonostage. I also use them inside my MK metal box main units too. I feel its a case of cleaning the audio window and helping keep noise at bay.

Works for me...

Try and see what living with it is like and then as Mike suggests remove them, that would make an interesting write up for SOG.


Regards D S D L

[Marco]

Cheers, Mikey and Neil - interesting.

Neil, I've found so far that they're particularly effective in-line with anything to do with the T/T, especially on the cables going into the SUT. I shall report more in due course

Marco.

[Mike]

I've added a couple more links to my post above, the last one is pretty, err, comprehensive!

[Will]

Well if you were into building high gain valve amps (phono amps) with valves such as 5842 and 6c45pi designed for vhf uhf you would realise the role Ferrites have in getting rid of hf uf hash.
Ferrites are added to to heater, grid, and cathode connections making them the only musical valve available in this application, ECC83 are dull and grey IMHO.
Will.

[Mike]

Hmmm... there's a bit of food for thought!

[Marco]

Very interesting, Will... Good job there are no ECC83s in my phono stage!

The Croft uses 6SL7s (NOS Brimar CV1985), but I've no idea how they compare to the 5842 and 6c45pi you mention. I suspect that, as usual, much depends on the circuit and how the chosen valves are implemented.

With regard to the ferrite chokes, so far I can detect no downsides: there is no rolling off of the higher frequencies, just simply a reduction in the noise floor and increased detail retrieval and clarity as a result. I'm quite pleased I did this

Marco.