Hi-Fi 101 Part 5: Cables


Let’s begin with a recap of the hi-fi 101 series thus far. In part 1, we introduced the series, and described some key terminology you’ll encounter throughout the rest of the guide. In parts 2, 3 and 4, we discussed the components of the hi-fi system, including the amplifier, source components (such as a CD player or turntable), and the loudspeakers. In part 5, we’re going to discuss hi-fi cables (both analogue and digital), explaining the name and purpose of each cable, the differences in higher-quality ‘audiophile’ cables, and we’ll also touch on the audiophile cable debate and whether or not high end cables can possibly make a difference to the sound.

It goes without saying that, without the necessary cabling, you’re not going to be hearing any sound from your hi-fi. Cabling isn’t just an accessory – it’s an essential. And, after splashing out on high-quality hi-fi components, obtaining good quality cabling is a must. Hi-fi cables usually fall into 1 of 3 main categories; Power, Signal (Analogue (both signal and speaker) and Digital) and Accessory.

Power

As with most of the cables that will follow, the purpose of the power cable is obvious – it transfers power from a power outlet to the power supply of your hi-fi component. Power cables come in all shapes and sizes, and the cable you choose will depend on the components you’re using. Some hi-fi components, particularly budget models, have permanently attached power cables that cannot be removed. Any new component will be supplied with a power cable as standard, even if it is a basic unit designed to ‘get you going’.

Common types of power cable include standard IEC, 20A IEC, and figure of eight. Standard IEC cables, usually referred too as IEC cables, 15A IEC cables or Kettle Leads are the same type of power cable used on your desktop computer. Such cables usually are of a 3-core, earthed design, and have a large rectangular plug with orientation cutouts on 2 corners meaning they will only fit in the socket in the correct orientation.

20A cables are very similar in construction, however are designed to carry a much larger amount of current. A 20A plug is much larger with no orientation cutouts in the corners. The blades (or connectors) of a standard 20A receptor are horizontal, meaning that despite its square-edge profile the 20A plug cannot be connected in the wrong orientation.

Figure of eight cables (usually abbreviated to ‘Figure Eight’) are the types of cables usually found in portable equipment such as portable stereos (or BoomBoxes) and some notebook chargers. They consist of a 2-core, non-grounded cable, offer less current capability, and are bi-directional – meaning they can be connected in any orientation. They’re not widely used in hi-fi – though they do make their way into some more budget-oriented models.

There is much debate as to whether a power cable can make a noticeable difference to the sound quality. Power cables other than those of a standard design can vary in their design and characteristics – some feature extensive shielding, some feature extra heavy duty cable, and some employ a special cable weave designed to reject RF interference and prevent such interference re-entering the mains supply. Whether their is any truth in the claim that power cables make a difference is for another post – this series is simply to outline the facts.

Mains Conditioners

While on the subject of power, we should take some time to discuss mains conditioners. The basic principal of a mains conditioner is to stabilise the power supply coming from the mains outlet, reducing any peaks and often removing any RF (radio frequency) interference present in your mains line.

RF is an issue that’s becoming even more prevalent these days, as our homes are filled with wireless devices, phones, TVs, computers and other electronic items. The most common cause of RF interference on the power line is poorly designed switch-mode power supplies. These power supplies use a transistor to reduce the mains voltage as opposed to a transformer, generating a lot noise and most don’t offer preventative measures to prevent that noise leaking back into your mains supply and thence into your hi-fi.

Furthermore, the supply coming out of the wall is not always running at exactly the given voltage for your country. The power output usually varies by a few volts depending on the load on the power grid. Mains conditioners filter out all this unwanted noise, and present your hi-fi with a clean, constant supply of power free from RF interference as well as the surges, peaks and spikes present in your usual mains supply. This means the power supplies in your hi-fi components don’t need to work as hard, in theory prolonging their lives and resulting in better sound.

Again, this is a topic that is often debated. Some claim that the other devices in your house (not the hi-fi itself) should be conditioned to prevent the mains supply becoming dirty in the first place. Some claim that the hi-fi components themselves are built to handle such issues, and therefore should be left untouched. And some claim the power conditioning and filtration has been the most worthwhile upgrade they’ve ever made to their system.

Analogue Cables

Signal cables

More commonly (and correctly) referred too as ‘interconnects’, signal cables are the cables designed to link your components together. They can be both analogue and digital, and coming in various forms with different connections.

Analogue

Analogue interconnects fall into 1 of 2 categories – Balanced and Unbalanced. Cables of a balanced topology include 2 signal conductors in reverse phase – both of which are processed by the receiving component, and any frequency which is the same in both positive and negative phase is canceled out, thereby potentially reducing noise and resulting in a cleaner signal especially over long cable runs.

Unbalanced, or ‘single-ended’ cables feature only 1 positive conductor, carrying only an in-phase version of the signal. Single-ended hi-fi cables are usually of the RCA variety – this is to say a stereo pair will feature 2 male RCA connectors (sometimes called Phono connectors or RCA/Phono connectors) at either end. Balanced cables typically utilise XLR connectors, and each stereo pair consists of 2 male and 2 female connectors at opposite ends of the cable.

There are various analogue cables to choose from at all manor of price points – some costing tens of pounds, some costing several thousand. The quality of the cables you’ll choose depends on the quality of the components you’re using, your budget and whether or not you perceive a sound difference between a budget and a high-end cable.

Many budget components will include a basic cable, usually of the single-ended variety, to get you going. Indeed, many budget components don’t feature balanced connections, as the necessary components are relatively expensive to implement and a single-ended implementation done right will almost always sound far better than a balanced implementation done wrong.

Digital Cables

Digital cables come in a few forms, including USB (for transferring audio data too and from a computer), optical toslink (a fibreoptic digital transfer cable), S/PSIF (Sony/Philips Digital Interface Format) or Coaxial cable, and AES/EBU XLR (of similar construction to the balanced analogue cables described above).

Digital cables are used to transfer digital data, in binary form, from A to B. In the case of digital optical, coaxial and AES/EBU cables, such data is usually transmitted from the source to the receiving device, and processed in buffer memory before being converted to analogue data and sent on to the amplifier. This means that the quality of such cables isn’t of particularly high importance – the general consensus being that if the data can get where it’s going with no errors, the sound should, theoretically at least, be perfect.

USB audio cables are similar in that they transmit pure digital data from your computer to a given USB device. However, the USB bus found on your average computer is noisy and suffers from interference caused by the switch-mode power supplies and the voltage regulation on your motherboard. Many USB interfaces, even those fitted to hi-fi components, don’t take their power from the computer itself – instead, they rely on the 5V DC(Direct Current) power supply provided by your computer.

Sadly, computers are rarely designed for audio use – and the power supply for the USB bus is primarily designed to power your peripherals such as a webcam or smartphone. Most professional audio recording interfaces utilise their own internal power supplies, and also contain interference filter – thence they do not utilise your computers power supply, and are able to filter out the interference on the USB bus. SUch filters are uncommon in hi-fi components, particularly at the budget end of the market – but they’re available as external units should you wish to improve your USB audio.

Typically, your hi-fi components will utilise a USB A-B cable, similar to that used by common peripherals such as a printer. As with any audio cable, hi-fi USB cables can cost anywhere from £10 to £10,000 and up. The most basic models employ thicker shielding in an attempt to reduce interference both inside the cable and from surrounding electronics. Higher quality cables are of a split design, whereby the USB power and data lines are separated – allowing you to power your device via an external power supply whilst the data is supplied by your computer.

Speaker Cables

Speaker cables come in various shapes and sizes – and, of course, various price points. Usually priced by the meter, hi-fi speaker cables can run you between £2 P/M for a budget model, running into the thousands should you decide to believe the hype and invest in audiophile cables. Speaker cables typically consist of a pair of coloured cables (usually black and red), denoting the positive and negative channels. Some cables use a stripe to denote the negative cable, negating the need for separate colours. To aid in flexibility, they’re nearly always multi-stranded conductors.

There are 2 common methods for speaker wiring – single wire and bi-wire. The single wire method, as its name suggests, requires a single positive and negative cable for each speaker. The speakers internal crossover then handles the splitting of audio frequencies between the speaker driver units. Bi-wiring is a method in which 2 runs of cable are used per channel, separating the high and low frequency information. Bi-wiring requires a compatible pair of speakers and either an integrated amplifier with a second pair of speaker outputs or multiple stereo or mono power amplifiers.

As with all cables, it’s important that your speaker cables are of an appropriate length to reach your speakers without putting excessive strain on the cable or terminals. It’s also important to use cables of the same length – as using cables of varying lengths can result in small time delays between the signals reaching each speaker.

Speaker cables can be terminated using several types of connectors, including banana plugs, pins, and spade connectors. Before these connectors became commonplace, speakers would be connected by simply stripping back a layer of the cable’s plastic insulation and connecting the bare wire directly to the terminals on both the speaker and the amplifier. However, terminated cables offer a neater connection often with better electrical contact, and also make disconnecting and re-connecting the cables for maintenance a far easier process. Some speaker cables are supplied pre-terminated with your choice of connectors, whereas most off-the-reel cables require you purchase your desired connectors separately and terminate them yourself.

Accessory Cables

Accessory cables are not crucial hi-fi cables. In fact, many top-end audiophile components don’t offer any features that would utilise such cables – trigger inputs and outputs, external remote control connections and multi-room capability, for example. However many budget models, and some higher end components do feature such capability, so for the sake of completeness we’ll briefly cover them here.

As mentioned, accessory cables exist primarily to allow you to utilise features such as power triggering (whereby the power cycling of 1 component is triggered by another), remove control signal transmission (whereby a component can send remote control commands to another via a cable as opposed to infra red), or for multi-room use (whereby an audio system can control, or be controlled by, a multi-room system).

Trigger and remote control cables are usually nothing more than 3.5MM mono minijack cables or standard RCA cables. As these cables only carry a tiny amount of voltage (usually plus or minus 12V in the case of a power triggering cable), the cable doesn’t need to be a high-current, high-voltage design. Furthermore, the operation of these functions has no affect on the sound quality – and such functionality is not susceptible to noise or interference, so the quality of the cable is also unimportant.

In summary; in part 5, you’ve learned the functions and names of the various cables used in hi-fi. In part 6, we’ll begin exploring the important specifications to consider when choosing your hi-fi components.
Continue to Part 6


About Ashley

I founded Audio Appraisal a few years ago and continue to regularly update it with fresh content. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. A musician, occasional producer and sound engineer, other hobbies include software programming, web development, long walks and occasional DIY. Follow @ashleycox2

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