The Systematic Approach – By Steve Elford

The Systematic Approach Blogs by Steve Elford – Part 9 'The Tracking Error Concept'

Here's one more concept to chew on - tracking error. “Oh no”, I hear you groan. But after my last blog in which I discussed transparency, we have to add one more critical concept - tracking error. Let’s start with why. You see, the transparency ‘with lenses’ debate is great, it really helps to get the idea of the weakest link in a string of components. But glass is passive, it doesn’t have to do anything to the image other than let it through. However, most of the components in a hifi don’t just let the music through in that...

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The Systematic Approach Blogs by Steve Elford – Part 8 'The Transparency Concept'

For this post I’m going to talk about an important system concept - transparency. Transparency is a term we often use when describing the sound quality of a component, and in our mind we usually think of things like good imaging and a lot of detail. But that’s missing the point. Let’s start from the basis that something that’s transparent will let things through - we say glass is transparent because it lets light through. A few hundred years ago people thought that window glass was transparent. But use it to make three or four lenses in a telescope and...

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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...

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The Systematic Approach Blogs by Steve Elford – Part 6 'The Basics of RFI and EMI'

Having discussed in detail the microphony issue in the last two blogs, it’s time to look at Radio Frequency Interference and Electro Magnetic Interference ((RFI and EMI). But let’s start at a simple level, just to check we’re all on the same page – with some science! Forgetting the terms RFI and EMI for a moment, let’s just consider basic signal theory. If you have two sine waves and add them the result will be quite literally at any point in time, the sum of the amplitude of both signals. If the sine waves are the same frequency and in...

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The Systematic Approach Blogs by Steve Elford – Part 5 'Microphony in Electronic Devices'

In my last blog I talked about the propagation of vibration through different materials and what happens at the boundaries of different materials. But this is of no interest if there is no consequence to it all. There is of course – almost all components in an electronic circuit are to some degree 'microphonic' - that is, if they are vibrated, they will turn some of that vibration into a small unwanted electrical signal, which is literally added to the actual signal we want to process. If we allow increasing levels of vibration to pass into our circuit components we...

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