hifi-advice.com - cable length

Opinions differ...

According to some, a powercable, but also a digital interlink has one defined perfect length, or should at least be a certain length. What's true about this? Without getting too much into details, here's a little theory first.

Theory regarding powercable length

Powercables also carry lots of disturbances besides the nice clean power. If several cables of equal length would be used, at least these (picked up) disturbances would arrive at the same time and thus do less harm. In this case you'd have best focus and detailling. Cables of various lengths would only diffuse the disturbances and hence the signals, resulting in less focus, more haze and a more loose bass.

A second possible explanation would be more obvious: the longer the cable, the more of its character shines through. This was later confirmed in listening tests, see below.

Theory regarding digital interlinks

"The shorter the better" is still popular when it comes to cables, but in matters digital this is not entirely true. For example, a digital cable can easily be 15 meters without discernible loss. This is however very much circumstance related and depends greatly on the equality of the sender- and receivermodule. The extreme example of 15 meters therefore can be a harder load to drive in certain circumstances. Transients can become softer than with the same cable in a shorter length. I've experienced this when connecting a PC that was in a different room. Surely there was nothing wrong with the sound via the 15 meter long Belden RG59 coax cable but when I brought the PC closer and used a 2 meter cable instead, the sound became much more rhythmic and had tighter bass. But these losses are of a friendly nature. The sound simply becomes more relaxed and less tight. Whether this is good or bad depends on your personal setup and tastes.

On the other hand there are people that say a digital cable always has to be at least 1-1,5 meters because of RF matters. There are in fact many complicated matters to digital sound that make an easy recommendation difficult. There's even the possibility that we don't completely understand everything about digital yet. But to stay with what we know: George Cardas says it as follows: "a length of 60-75 cm is best avoided because of common radio frequency antenna lengths. In general it is said that digital cables should be longer to form a proper transmission line, but in reality you would never be able to make them long enough to cover all intervals." And then he continues with a lot of theoretical stuff that is mostly beyond my comprehension.

I've always been more of the "just listen" kind of school. I think that there are parameters in a cable that influence the sound much more than possible pickup of radio waves. All cables have a sound and it is this sound that you either like or don't like.

Powercables - In practice

Even though the theory says that the cables should have equal length, I cannot confirm this by performing practical tests. In the reference-setup I've performed several tests and they show that shorter powercables have more attack, and are more dry while longer powercables are mofe fluid and more relaxed. This goes for Lapp as well as for Belden powercable.

Digital Interlinks - In practice

The end result depends greatly upon the quality of the source and the receiver in the dac. Explaining this could leas to a very long story so I'll suffice in saying that it is a very relative matter. Also, even though die hard technicians claim otherwise, reclocking doesn't make the dac impervious to the quality of the input signal. This is something I have tested over and over again with a lot of different sources and dacs.

One dac can be very sensitive to the quality of the input signal (jitter) and can therefore be more reactive to a longer cable whereas another dac can be relaively immune to it. Despite this, I have not been able to discover a difference between 50cm and 150cm cables. I do however find that a very long cable makes a difference, for the worse. 10 meters is a length that for critical listening is best avoided. Even though dacs usually lock perfectly fine, even when using lengths well above 10 meters, you can clearly hear degrading of the signal. Edges are softer, dynamics are rounded off and there's some overall lack of energy. This has been noticed with the following dacs: Wadia 861, Audiomeca Enkianthus and the DCS Purcell/Delius combo.

Bottom line

With powercables it remains a matter of just trying it out. Different setups may require different "optimal" lengths of cable and personal taste is always a factor. For digital interlinks it is more clearly cut: 1 or 1,5 meters doesn't make a lot of difference and even shorter doesn't have any advantage so I'd stick with at least a meter, or longer if you swap your components around frequently, like I do:-)

Happy tweaking!