Mains Filters.

[DarrenHW]

I recently picked this up:



Having heard the benefits of Marco's Tube Distinctions digital noise filter I was keen to give it a go. Finding it easier to see than hear changes the first piece of equipment I plugged in was the TV, this had a very positive effect with big improvements in detail, focus and depth with the picture becoming more vivid. Encouraged by this I plugged in the Oppo and played the same test scene's. Again this yielded similar improvements in detail, focus and depth with a further improvement in colour, greens are more green, blues are more blue etc... What was also obvious from the beginning of the first test scene was that the sound had changed, so after judging the changes to the picture I switched to some FBA from the Oppo. Most prominent was the change to the bass, whilst there is less bass it is tighter and more textured, a change I will happily trade for bass volume. I would say the improvement to the sound mirrors the improvement to the picture it has more detail, depth and most satisfactorily focus. I don't know whether focus is the right word but there is a marked improvement to the centre image, which as I sit ~750mm off centre tis very welcome.

My first experience of mains filters has been very positive, what are other members experience of mains filters (good or bad), any recommendations for budget or DIY mains filters for AV use?

[Wakefield Turntables]

I owned an Isotek Titan for a while and thought it added nothing to my system so I flogged it. I then went completely hatstand and bought the PS Audio P10 and now wouldn't be without it. Yes it's the other end of the spectrum with regards cost but it really does what it says on the tin. I notice that my system's soundstage (the 1210) suddenly looses focus and cohesion, bass is marginally down and micro detail starts to disappear. You could also try and buy some Ferrite coils off ebay, usually a few quid. I have them placed at the very beginning and very end of each power cord.

[DarrenHW]

I just looked up the P10, that really is the other end of the spectrum! Interesting findings though, do the same results apply with your Garrard?

I do plan on trying some ferrite coils on the mains leads, I'm trying different wires and configurations at the moment to see which works best with each piece of kit.

[Marco]

Nice one, Darren - always good to get a tangible improvement with some tweaking!

The level of 'success', or otherwise, achieved by installing a mains filter, is down to three main factors:

1) What the filter in question has been designed to do - and how good it actually is at its job.

2) How dirty/noisy the mains is in your area, in the first place.

3) The type of components used in your system, and how much noise they chuck back into the mains supply, thereby 'contaminating' the other kit, powered from the same supply.

The Tube Distinctions unit I have is designed to tackle the latter (shielding my system components from the effects of 'digital switching noise'), and excels at 1) above.

The fact is, digital components and systems are (in general) intrinsically noisier than their analogue counterparts, mainly due to the clocks inside DACs, which when doing their job of converting digital data into an analogue signal, introduce 'switching noise' onto the mains, which in turn 'contaminates' (with that noise) the other components in the chain. That is what the TD digital noise filter I use is designed to eliminate, by filtering that noise to mains earth, instead of allowing it back onto the mains supply, to be picked up by the rest of the system.

It's highly effective, and works completely differently from other units that are designed simply to filter and/or regenerate the whole mains supply, and in turn (in many cases) notably increase impedance, which is not a good thing. Therefore, the fundamental sonic effectiveness of any such 'all-in-one' filter/mains regenerator will depend on whether the effect of cleaning up a dirty/noisy mains supply outweighs the negative effect of increasing the impedance on said mains supply, which ALL filters/mains regenerators do, to a greater or lesser degree.

That is why their efficacy (or otherwise) is reported differently by those who use them.

The other thing that makes digital systems (and components) in general noisier is the fact that most of them employ the use of switch-mode PSUs, often of poor quality, instead of properly designed linear PSUs, which is why paying proper attention not only to how the digital equipment you buy has been built, but also how you connect it to your mains supply, is vitally important if you want to get the best sound.

In that respect, digital equipment, when possible, should always be powered from a separate mains spur, or at least plugged into a separate mains block from your other kit, in order to isolate (to some degree) the other components in the system from the noise that it generates.

Anyway, enjoy your new improved sounding music!

Marco.

[Marco]

I should add that if anyone is interested in purchasing a TD digital noise filter, that they are being distributed by Mark Grant Cables, so contact Mark on here for more details

Marco.

[DarrenHW]

Thanks Marco, an interesting and informative post .

[Marco]

No worries, dude. It's an area of audio where I've done much experimenting!

Marco.

[Wakefield Turntables]

I just looked up the P10, that really is the other end of the spectrum! Interesting findings though, do the same results apply with your Garrard?

I do plan on trying some ferrite coils on the mains leads, I'm trying different wires and configurations at the moment to see which works best with each piece of kit.

I've not used the 301 on the P10 yet as its at the other side of the room and I cant be arsed re-wiring everything. I will be having a little room reorganising and intend having the 1210 and 301 next door to each other so the 301 will have access to the P10.

[DSJR]

My experience is that the filter components must have a high current rating. The 6A rated Roxburgh filters I use are only used with one source each and I have a memory of a HFN article where Ben Duncan (I think it was) did some tests and found that a filter rated at ten times the component it was used with, offered little resistance to sudden current demands (I think I have this right).

Where we used to live, the above filters helped no end. Living on the coast, our mains in town is pretty clean and they make little to no difference, although I still use them on digital sources.

[DarrenHW]

Are these http://www.ebay.co.uk/itm/Roxburgh-E...m3aae7dc706the the Roxburgh filters you're referring to David?