Saturday, June 21, 2014

Power Cords

I've released two new Power Cords. Well, I call them power cords, but they are really BlackDiscus-based power filters with power cords attached. Their performance mostly comes from the filter. The power cord part on it's own sounds pretty good but not in the same ballpark.

NEO Power Cord

So why power cords? How on earth can they make any difference?

If you listen to the flat-earthers at diyaudio, they will tell you that the power has already gone through miles of very ordinary copper and what possible difference could the last meter make. 

But like many common sense observations, the truth is more subtle than that. It's best to look at the power delivery system of your whole audio set-up. Some lucky folks have separate lines for their audio system, and I'm sure that really helps. Then you don't have to worry too much about all the computers, air conditioners and so on.. But usually there's a range of audio gear powered from essentially one source. There's power amps, with their strange, music-modulated power grabs, taken in sudden bites 120 times a second. Then there's digital components with corresponding HF interference. But to think that it's all just current through wires is also a gross simplification - currents have associated magnetic and electric fields. Then there are the external fields that are all around, nowadays reaching well into the gigahertz range where it's real hard to get a handle on without huge amounts of money. 

These fields all interact in predictable, but complex ways. 

Looking at the way components draws current is instructive. Anything that uses DC for power will need a power supply that converts AC to DC. That means all audio gear. And these supplies inevitably contain rectifiers, which switch the current on and off, either 120 or 100 times a second (depending where you live).

Engineers call this "a horrible power factor". And no, it's not possible to fix up this kind of power factor problem with a few capacitors. In fact it's darned nigh impossible to get a power amp to present a benign load.

Picture a pipe with a high pressure water supply at one end. At the other you have a electrical valve that operates almost instantaneously. Consider what happens if you switch the valve on and off rapidly. It's not hard to imagine the back-pressure waves in the pipe, and those waves causing problems for other users of the same supply. In fact this problem occurs in real life with water supplies.

This is what is happening in your power amplifier's power cord. (well, not literally, but you get the idea).

So one of the purposes of the BlackDiscus filter is to help isolate the power amp from the other parts of the system. In other words, to filter the junk coming out of the amp onto the power supply system.

Then there's the more obvious function, which is to filter noise and interference from the mains supply. Note that some of the noise and interference might be coming from other components..

FIRST Power Cord.

There are two models of Power Cord - FIRST ($139) and NEO ($399). They differ in the type of filter. 

FIRST uses 3 Kegs. Two are special magnetic Kegs, on Live and Neutral, with a normal Keg on Earth.

NEO uses a "Power Purifier" style filter using 3 Blue Sticks, as well as a 3-Keg filter. This uses magnetic Kegs with Neodymium magnets inside. 

Note - don't think that the Neodymium magnets are somehow more 'high end' than the kegs used on the FIRST cord. They are simply the right ones for the job. Actually the kegs used on the FIRST are much more hassle to make and also cost more. If you swap kegs between the NEO and FIRST, the result is that the FIRST would have excessive sibilance, and the NEO a slightly recessed top end.

This is also the reason we are not doing versions with more kegs. This is the right number. If you put more on, you get worse sound, less balanced.

The FIRST Power Cord is a complete bargain. It won't stay at $139 for very long. It sounds much more similar to NEO than different. NEO is more refined and sounds more real and 3D, but if they were priced according to their performance, FIRST would cost $299  (if NEO is $399)

I think it's likely that these Power Cords will be classed as giant killers. I've never heard a Power Cord make anything remotely like the difference that these make. But the most expensive power cord I heard only cost a mere $1200. (But others tell me that the NEO beats cords costing much more than that)

More info here