Earth, signal ground and noise
Audio engineers typically put a great deal of effort into making sure that the positive rails of their DC power supplies have, among other things, low ripple and noise. However, considerably less thought tends to go into the negative rail and the signal ground plane.
In an audio system there are two independent reference points from which voltages are measured: earth and signal ground. For safety reasons all external conductive surfaces of audio equipment must, by law, be connected to earth. Signal ground (which is typically not connected to earth, but in some cases may be) is a point to which all signals within the device are referenced, and is the "negative" side of an electrical connector – whether RCA, XLR, USB, etc. So when you measure, say, a component’s signal/noise ratio, dividing the maximum output of a device by its minimum output, the reference point for both measurements is signal ground.
But if the ground plane has noise on it, then such specifications can be misleading. You can have a very good signal/noise ratio but in reality your system can have considerable noise on the ground plane.
CAD’s Scott Berry, an audio engineer already known for thinking outside the box, strongly suspected that reducing high frequency noise on the signal ground plane could be a key factor in ensuring the clearest possible sonic platform for a hi-fi system. So Berry did what any curious engineer would do and put his suspicions to the test.
Situation under control
The purpose of CAD’s GC1 Ground Control is to reduce high frequency noise on the signal ground plane.
Like any electrical signal, this high frequency noise will always seek the path of least resistance and flow around the system searching for a place to ground. The GC1 provides a simple and effective route for it to do so and then converts the noise into heat.
The GC1 Ground Control’s methods for achieving this are something of a closely guarded secret, but involve a highly complex combination of proprietary materials, borrowing technology from aerospace engineering and featuring an ultra-precise internal configuration and construction. Being a passive device, it does not plug into any mains power. Considerable attention has also been paid to its cables and connectors, since it is essential that the route from signal ground into the GC1 is the easiest one that the high frequency noise can take.
The GC1 Ground Control can be connected to any audio component that has an unused input or output connection. Whether a DAC, streamer, computer, CD Player, NAS, router, phono stage, preamplifier, amplifier, etc – if it has a spare input or output connector (RCA, XLR, spade, USB or Ethernet) then you can plug in the GC1 Ground Control whose sleek, hyper-minimalist design will fit discreetly into your system.
Each GC1 sports two connectors - allowing you to hook up two components, to use both connectors for a single component or to daisy chain more than one GC1 to a single component. A choice of cables with various connectors is available; one cable is included with each GC1 while additional cables are available for trial and for purchase.
The GC1 Ground Control can also be attached to earth. If you have any type of earth connection on your audio system or power distribution, CAD can supply a cable with an appropriate connector that will fit. And since any audio component with a conductive case must have the case connected to earth, the results of reducing high frequency noise on earth and therefore on your audio component can be breathtaking.
A significant sonic upgrade
“The sonic result is more significant than you might think,” says Berry, smiling (he has very much enjoyed demonstrating the GC1 at several events and watching jaws drop in surprise at the audible difference in sound quality).
“Experience has shown that the best results are usually achieved by connecting the GC1 to the device in your system that has the highest noise levels,” he adds. This will tend to be components such as computers, audio servers, DACs, CD players, NAS, routers, etc.
Expect liberated dynamics and a sharpening of pace, rhythm and timing. The soundstage becomes both wider and deeper, with a magnified sense of presence and performance. Toning is more truthful, such that voices and instruments sound distinct and authentic. And of course the background silence is that much more silent, against which every frisson reveals itself more clearly and each recording - regardless of style or genre - gives so much more.
Dimensions: 322 mm (w) x 88 mm (h) x 111 mm (d)
Weight: 4.65 kg
Pricing and availability
The CG1 Ground Control is available now, priced at £1,650 (incl. VAT) including one cable, terminated as required with a choice of spade, banana, XLR, USB or RCA connector.
Additional cables are priced at £250 (incl. VAT).