An often-ignored area in high fidelity systems is the cabling connecting the various components. Interconnect leads should be high quality cable with substantial terminations. Gold plate is inherently resistant to corrosion, and an excellent conductor. The presence of corrosion induces distortion and poor conductivity will seriously interfere with sound quality. Terminations must plug snugly into sockets to maintain maximum conductivity and to avoid annoying earthing problems.

Speaker cabling is equally critical. Use only solidly constructed cable of high purity copper or silver content. Again, gold plated terminations are recommended, of the spade or banana plug type. Use cables of equal length and as short as possible to maintain uniform electrical resistance at the lowest possible level. If your amplifier is closer to one of your speakers than the other, avoid coiling the longer lead as this can create inductance, with the potential of reduced high frequency performance. Keep all connections clean, firm and tight. The traditional adage that a chain is only as strong as its weakest link most certainly applies to audio systems.

Bi-amping uses two similarly powered amps, with exactly the same input sensitivity so that, when the same input signal is provided to each of them, the output level will be exactly the same. This can often be done with an integrated amp connected to the tweeters and a power amp to the woofers etc, as it spreads the power requirement between the two amplifiers. It can also be done using dedicated power amplifiers. Bi-amping can achieve greater control, dynamics and resolution than if you try to run everything from a single stereo amplifier.

The use of the high quality Perreaux balanced signal inputs and outputs can have the effect of cleaning up hums, buzzes, radio frequency interference (RFI) and general extraneous rubbish that can enter an audio system. A balanced signal input system operates on the principle of differential amplification. The positive and negative inputs are contrasted against one another and the difference between them is amplified. Noise entering the system is imposed equally on the positive and negative signals and therefore will not be amplified, as no differential voltage exists.

The term used to describe the quality of the effect is called Common Mode Rejection Ratio (CMRR). CMRR is an equipment and system specification, which describes how well unwanted common mode signals are counteracted when used in conjunction with balanced connections. CMRR action prevents the egress and build up of extraneous hum; buzzes and RFI when analogue signals are conveyed down cables and between equipment powered from different locations and is widely used in professional audio applications.

The rejection ratio achieved is described in minus dB. The CMRR of a system follows the formula 20Log(Voutput/Vinput). In other words a CMRR of -40dB means that all garbage entering the unit will be made 100 times smaller. The piece of equipment with poorest CMRR will effectively determine the hum and RFI level of the system. Effectively the weakest link in the chain. Highest quality audio systems should quote a CMRR figure of -80dB or better.

For optimal listening pleasure, we recommend using balanced signal inputs.

Positioning of your source equipment (tuner, video, disc, tape, record, decks) is important. To avoid airborne frequency peaks, place them well away from your listening area.

Loudspeaker placement is a controversial issue; suffice to say that room corners are generally the worst situation. Everything that constitutes your listening area, including the materials used in its construction, will affect the sound itself and the sound stage created. Equally, you have to live with your system and therefore

compromises will have to be made in line with your particular priorities. The best advice we can give concerning the choice of loudspeakers is, establish clearly in your mind your requirements; listen to many makes and models, and if at all possible audition your preferred choice in your own listening area and trust your own ears.

The concept of running a dedicated AC supply for your hi-fi system can provide real improvements to your listening pleasure. The reasoning behind this is simple, as in many instances mains supply impedance is too high to provide adequate levels of current as can be demanded by your Perreaux amplifier. Mains supply problems can compound dramatically when used in countries that have lower (120V) mains voltage. In these instances the current supply will be increased in direct proportion to reduction of mains supply voltage, further ensuring the need for a mains supply is of sufficient quality. A dedicated mains supply to your audio system requires the use of heavy gauge mains cabling, outlet receptacles, correctly sized circuit protection device and earthing. Dedicated AC supplies can also work to prevent induced interference emanating from solid-state light dimmers, computers and other electrical appliances. In addition to supply cabling, special attention must be given to earthing. Correct earthing is essential to minimise the possibility of noise being injected into the system and to reduce the likelihood of hum being created by ground loops. Ensure that the earth is solid, clean and noise free. With any earth system the resistance of the mass of the earth itself is an important factor. The highest value of earth resistance occurs in the area surrounding the earth electrode. The size of which depends on the resistivity of the surrounding soil. Soil type and structure can lead to surprising differences in resistivity values. Clay can be as low as 8 ohms per meter whilst an earth electrode of similar size bedded into sand can be as high as 1000 ohms per meter. Excellent results can be achieved by upgrading your earth electrode and connections.

When matching speakers to amplifier wattage - ordinarily, the amplifier should have a continuous RMS output power rating the same as or higher than the speakers at the same impedance rating. For example, 200Wrms, 8Ω speakers driven by a 200Wrms at 8Ω amplifier is not as ideal as 100Wrms, 8Ω speakers driven by a 200Wrms at 8Ω amplifier.

High fidelity systems are an investment deserving of careful thought and personal time. Your preferences, priorities and constraints will dictate the parameters of your purchase, your ears will tell you what is the right choice for you. Our experience tells us that the bitterness of dissatisfaction lingers long after the fragrance of cheap price is forgotten, hence our use of the term - investment.