Burley Wire

Balanced interconnects are the choice of professionals for a number of good reasons, dramatic reduction of system noise being the most important. The classic single-ended (RCA) interconnection is prone to picking up noise in an audio environment, particularly magnetically induced ground noise.

A ground loop is a condition where the input(s) to an audio component don’t agree with the audio source component as to exactly what ground is. This occurs because the magnetic environment induces circulating currents through all ground connections which are part of loops.

Ground loops are often formed between two cables which share a ground connection at the source and at the input, and you can literally see the physical loop. Another common loop is formed between interconnect grounds and the common grounding in the household wiring system.

Either or both of these loops can have circulating noise currents induced by the magnetic fields of the household wiring and by the power transformers in audio equipment, video screens, and household appliances. These noise currents create voltage drops across the resistance of these ground paths, and this sets up a situation where not all parts of the system agree as to exactly what voltage is ground. The result is audible noise. A quality power amplifier will have a noise spec in the region of 200 microVolts or so, which is not very audible without putting your ear right against the loudspeaker cone. Plug that amplifier into an RCA connected audio system and you will typically see noise on the order of 2 mV, which is 20 dB higher. This amount is very much more audible.

The traditional response to these problems is to break the loops where possible and/or to use balanced interconnects with Source and Input circuits designed for balanced operation. With balanced lines, the signal is sent down the cable over two lines operating in opposite phase. At the receiving end, the circuitry amplifies the difference between the two signals, and rejects those voltage components which are the same. As a rule, the two lines pick up noise in about the same proportion, so the input circuit rejects the noise.

This works great, but what do you do when your source equipment is single-ended and your amplifier has a balance input? Traditionally, you ground the negative input, and operated the amplifier single-ended.

However there is a much better way. The diagram below shows the three scenarios for operating interconnects:

At the bottom, you see the conventional single-ended (RCA) connection, which is so problematic.

At the top you see the balanced line solution which uses a balanced source and balanced input to get low noise.

In the middle you see the BBC interconnect, which takes its negative input from the original source ground. Any noise picked up by this cable is intended to be equal on both the signal and reference ground, to be rejected by the balanced input on the receiving end.

The result is a dramatic reduction in the output noise of the amplification system. In real audio systems, the BBC interconnect has been shown to reduce the hum and buzzing of ground noise pick-up by about 20 dB better than quality RCA cable. This is not a nebulous subjectivist performance improvement – it is easily measured and easily heard.

BBC interconnects are made of the finest professional balanced cable and the highest quality RCA and Neutrik XLR connectors. The design has been compared to some of the finest RCA cables available on the market, and with a single-ended source and a balanced input amplifier, we have not heard better. The dramatic reduction in noise alone is sufficient to open up the dynamics, soundstaging, and clarity of any audio material. If you try it, you will not be disappointed.

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