March 2010
This section contains some very important information not normally discussed by hifi retailers, but well known to the obsessive hifi nut. Most hifi retailers aren’t really interested in getting the best out of the equipment you buy. For them it is more profitable (and a lot easier) if you just upgrade your equipment every few years with a more expensive unit.
We know how to get the best out of any equipment. Music is such a large part of our lives and we have been known to be just a little obsessive about our systems… We are tweakers at heart and have made many simple modifications to elevate the performance of even highly regarded hifi brands. A lot of our friends share this passion and some are downright obsessive – even borderline crazy – with the lengths they will go to. Fortunately, you needn’t go to extremes to get significant improvements. Simple changes often make a startling difference.
We have distilled years of knowledge into this resource. Years of tinkering to get the best out of our equipment. Some remarkable results can be achieved. It often costs very little to get performance improvements comparable with a much more expensive system.
Read on to find out what you can do to make your system really sing.There are four main areas that affect a hifi system.
March 2010
The Mains Supply
“The mains power supply?” I hear you ask. How on earth is this relevant to hifi? It simply provides the power. It is a little known fact that your 240V mains is one of the most important factors in getting the best out of your hifi system. You may have heard it said that the most important component of the hifi chain is the source component. After all, garbage in, garbage out! But have you considered that the ‘source’ of power for your entire system is the mains?
Nobody thinks much about the 240V mains power that comes into your home. You flick a switch and the light comes on. You press a button and your kettle boils. Its just there. It powers everything in your home and nobody gives it much thought.
However to those in the know, your mains supply is a double edge sword. It provides the power for your entire hifi system, but it also poses a deadly threat to musical nirvana. Have you ever noticed how involving your hifi system sounds at the end of a late night music session? The reason your system doesn’t normally sound as musically involving and dynamic as it does late at night is because of mains voltage problems.
To understand why, we need to explain a little of how the electricity supply works and how it impacts your hifi system.
The power supply section of your amplifier (for example) takes this oscillating voltage and creates a stable constant voltage level called the supply rail voltage that powers the sensitive circuitry. The power amplifier uses this stable supply voltage to create the output voltage used to drive the loudspeakers. It uses the delicate low level input supplied from the preamplifier or source component and boosts the level with power from the supply rail.
Here is the important part. Any variation in the supply rail voltage finds its way into the final output signal corrupting the musical signal. That is why the power supply section is often the first part of an amplifier that hifi tweakers modify and improve. In all but a select few of the finest components available, the power supply is compromised by design, typically because a product is designed to a price point.
So how does the mains supply affect the supply voltage (and hence the music) and why are we so concerned about mains anyway?
Irregularities in the mains supply from your power company are a part of life. The voltage can be higher than 240V, lower than 240V, there can be irregular sags and dips in the voltage, there can be voltage spikes, fluctuations in frequency, and the list goes on. In fact, all the electricity supply company is obliged to do is provide ‘roughly 240V’. They generally have a tolerance of 10% which means it can vary from below 220V right up to 265V and still be OK from their point of view.
All of these types of irregularities find their way through the power supply section and cause variations in the supply rail voltage. This then affects the delicate audio signal leading to a degradation of musicality. More on that later…
Now, let’s take a look at the different types of mains problems in a little more detail and how to overcome them.
High or Low Voltage
The Mains voltage at your wall socket should ideally be 240V rms. I won’t go into the details of what “rms” means, other than to say it is a complicated measure of the average AC voltage. The actual voltage delivered can be very different. As previously stated, it can be anywhere from about 220V to 265V and still be considered correct. Moreover it can vary considerably over short periods of time.
To understand why you must consider how electrical power gets to your home. The power station generates very high voltage in the order of hundreds of thousands of volts which is most efficient for transmitting over long distances. High tension power lines – the very high towers running from the power station to the city as shown in figure *** (a) (High Tension Power Lines) – carry this voltage. A local substation takes this high tension voltage and drops it down to around 11,000 volts for transmission along city streets (figure ***(b)). The last stage of the power chain comes with a Stobie pole mounted transformer which takes the 11,000 volts and drops it to the 240V that you use in your home. It is a very long chain with many steps down in voltage. This is part of the reason 
that it is difficult to maintain an exact 240V level at every house.
to be continued….
