Audio Media - September 2008 - (Page 63) POWER FACT & FICTION can’t apply a rule and say that it’s always going to work the same for everyone. I’ve heard differences with balanced power when it’s been put into major studios that were having strange problems with ground issues or softness in the low frequencies. Then after going to a balanced system, the entire sound was appreciably better. So it seems like balanced power is just one more step towards getting the cleanest possible power to the equipment. In my thinking, it's one of the most important investments that anyone can make in a recording studio or an audio production environment.” different studios, and I can almost tell which ones are running a clean power scheme versus ones that are not. The differences I heard after going to balanced power were drastic. I can turn my monitors up to full power and not hear any noise at all – I would classify it as a improvement in my noise floor, and that is a very important .” “I am working with a classical harpist in a mastering capacity and she is worried about having to re-record her record. She sent me a track containing actual radio chatter somewhere around - Db full-scale – you can’t do anything with that – the track is ruined. If the studio that recorded that had balanced power and proper conditioning their client wouldn’t have to be searching out other recording studios to redo the work – and I hear stuff like that quite a bit.” > use were derived from practices established over a century ago, employing a three-wire distribution scheme in which branch circuits have a hot wire and a neutral wire, with the neutral tied to a third wire connected for safety to an earth ground. This unbalanced scheme can create significant hum in audio circuits. The current flowing in the hot wire induces hum in any other nearby wires, which may carry vulnerable low-level audio signals. This low level noise then becomes part of the audio itself. In a balanced power conditioner (in our case a Furman ITII) a centre-tapped isolation transformer allows the AC power feeding a studio to be balanced at its source. The currentcarrying wires then are no longer ‘hot’ ( V) and ‘neutral’ ( V), but two V lines of opposite polarity whose difference is V. This type of power, when run around a room, does not induce hum into nearby audio wiring, because the two conductors induce equal and opposite voltages that cancel each other out. Similarly, ground currents are all but eliminated by the same common-mode cancellation effect. Even further, the Furman IT- II features a centre tap ground lift, which may reduce ground induced noise even further. I asked Mr. Givens to share his thoughts on balanced power: “More than any other area it seems that audio production really needs good clean power. Whether it’s in the analogue world or in current digital studios, good clean power is essential and it really does affect the quality and the definition of the sound. Going to a balanced system may not be appreciated in everybody’s setup. Again it’s one of those things where you A proven case study in balanced power is the mastering facility of Cass Anawaty. In Portland Oregon Cass specialises in high-resolution stereo and surround mastering for major clients: “The obvious benefits in a balanced power setup are the actual rejections and cancellations that occur, but the real impact that I see in my facility is the increase in headroom. When performing multiple digital to analogue and analogue to digital conversions and processing via an analogue signal chain, the conversion needs to be as clean as possible. Most people are aware of this but they don’t usually think of it in terms of power. With reduced oscillations on the line you have a lower noise floor, and you can actually see this on the meters… in analogue or digital gear – and that equals more headroom in my business. With the current state of convertors you are already losing bits to the noise-floor within the convertors themselves, so anything you can do to preserve any amount of headroom is always a very positive thing.” “Many of the power strips suggest that they perform some sort of RFI or EMI rejection, but I’ve found that I get an even cleaner signal by using a balanced power system. As a mastering engineer I get a lot of different material from A Cass Case “There will be no bench tests, specs, and measurements – I want to hear the goldeneared professionals tell us what they hear, or don’t hear, in a different cable.” I myself have been running the Furman IT- II in my studio for a few weeks now and I am blown away by the audible reduction in noise floor. I experienced the exact same thing that Cass claimed with my ADAM studio monitors. My Apogee convertors and True Systems microphone preamplifiers are benefiting from balanced power as well. When I started researching for this feature I didn’t even know what balanced power was, or how it worked. To think that for the last ten years I’ve been running only a small Furman PL- power conditioner! Who would think that the positive impacts of balanced power would be so dramatic and obvious? Any passionate engineer, musician, or sound designer would be foolish not to look into a balanced power system – especially those who have invested much time and money into creating a great sounding room with high-end gear. B alancing The B enefits Are you going to tell me that a different power cable can make things sound better…? I know that this topic enrages some and fascinates others, but Power Cables > A1 Discrete Class A and Tube Dual Preamp / DI A2 Discrete Class A and Tube Stereo Processor Ice Cool Looks Discrete Class A Electronics Plus Tube Warmth All Ebony Series feature tube stages with variable drive in addition to the discrete Class A circuitry putting you in total control of how ‘warm’ or how ‘cool’ you want the sound. From £499 ex vat. PASSIONATE ABOUT TUBES A3 Discrete Class A and Tube Mono Channel Strip tlaudio.co.uk N EW A4 Discrete Class A and Tube 16:2 Summing Amp http://tlaudio.co.uk http://tlaudio.co.uk
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