Ground zero for AC distribution?
By Roy Gregory
AC supply is both the bedrock and one of the least appreciated aspects of audio system performance. When it comes to the best way to get AC power into your components, there is almost zero consensus, with options ranging from sophisticated super-cap, pseudo battery supplies to a bank of actual batteries equipped with a convertor, from isolation transformers to ‘industrial’ filters, ‘regenerators’ to balanced power supplies. At the other extreme, there are those who rely on a row of multiple wall sockets. As a reviewer, the latest fad inevitably comes your way and, as a result, you name it, I’ve tried it. But the real problem here is that any solution will be situationally dependent. Even if I come up with a definitive arrangement for my specific system requirements and situation, there’s no guarantee that it will work for a different set of components in a different electrical environment.
We need to divide this into two problems: everything up to the wall socket – and everything after it. My default position – the one from which I start with any system – is a separate, dedicated AC feed, along with a parallel clean ground, running to earth posts in the yard. That gives me a single point of connection for the AC input and the option to connect to the parallel ground in addition to the safety ground that’s an essential part of the AC supply. Do not be disconnecting the AC ground: it’s not good for your buildings insurance, your system sound quality or your health! It’s also a straightforward piece of electrical installation that any contractor can carry out for less money than most of us spend on a set of cables. Once you’ve committed to a dedicated line, there are levels upon levels of hardware that might be applied to the problem, but even using carefully selected and installed domestic hardware is going to deliver a major performance boost.
Next step is to use an audio specific distribution block to feed the system. For almost 20-years now, my weapon of choice has been the Nordost QBASE QB8, an outwardly straight-forward, eight-way distribution block. But, being a Nordost product, it’s not without its wrinkles. For starters, it’s star grounded and employs a focussed grounding system to ensure that the ground paths converge at the centre of the star. The casework and internals are mechanically tuned and the extruded body is both robust and stable. Given the no-nonsense nature of the beast, it’s no great surprise that it’s been the first unit I reach for whether I’m using Nordost or some other cables.
The QB8 has evolved and improved over the years and now boasts a Mark III suffix, with each subsequent version showing worthwhile advances in performance. However, it is still essentially the same beast that first appeared way back when, with the same form-factor and the same raison-d’être: to provide your system with the most direct, organised and lowest impedance AC feed possible. The QB8 does and always has done, exactly what it says on the tin.
