The Systematic Approach Blogs by Steve Elford – Part 7 'Thinking of your system as a noisy network'

In my last blog I outlined what RFI and EMI are. The next step is to think more about how these two things behave within our hifi systems. Over the thirty-plus years I’ve been researching this (gosh, that long?) one thing that has been repeatedly so obvious is that RFI/EMI is incredibly pervasive and invasive. Given the tiniest chance, it will go anywhere and everywhere. So many times I hear people say things like “you can stop RFI with one mains conditioner”, or “a simple filter built into a component’s power supply is all you need”. No, each one of these can only serve to reduce RFI in that path! RFI can bypass a mains conditioner if you have just one of your components plugged directly into the wall for example. Also, this thinking implies that RFI just comes in from the mains – not true. I would say that most of the damaging RFI in a system has been generated by the system. Oh, I’ll put a caveat on that - it’s probably not true on a very basic system topology such as vinyl and valves with no logic control or display systems, but then, in such a pure system, EMI from all the other household transmissions gets in there and pollutes it anyway – so you still need to take care of the problem.

We can think of EMI as coming from two fundamental sources; all our modern household systems around us and from within our system components themselves, So because of this we can think of how we reduce the problem in two different ways also. We can for example put a bit of distance between our hifi and ‘big transmitters’ – computers, routers and big AV systems say. We can keep potentially noisy cables away from sensitive analogue ones as well. The second way is to tackle EMI within the system itself. We can be more selective in our choice of components of course – many manufacturers now include good noise reduction strategies such as avoiding switch mode power supplies. And we can remove some of the EMI from our system too with EMI absorbent cable technology and even RFI grounding products like our very own Vertex Classic Picos. Remember that when I say RFI grounding, that takes the RFI away so it can’t radiate around inside your equipment as EMI.

In my next blogs I will start to discuss and break down systematic strategies in detail – how we really might start going about managing vibration, RFI and EMI, and also how that becomes such an important element of our overall system building strategy. Oh, and some simple tips that you can try for yourself that won’t cost you a penny!


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