Friday, 25 April 2014

Power Crazy

My first exposure to the crazy world of cables was in the very early 1980s, when a friend of mine purchased a DNM preamplifier.  Dennis Morecroft told him that to get the best out of it he would need a special (read expensive) Japanese interconnect cable to hook it up to the power amp.  My friend duly borrowed said cable (which had a worrisome propensity to fall apart whenever you unplugged it) and we took a listen, and I have to say that there was definitely an improvement, and that blew us away for a while.

Shortly after that, a craze developed in UK audiophile circles for using solid-core loudspeaker cable.  This was something else I had to try out, and was quite easy because you could buy solid-core cable of the right gauge by the reel from the local hardware store - it is the same stuff you wire your house with.  Using this solid-core cable made a significant improvement to the bass weight of my speakers, and the imaging seemed cleaner too.  With most of the reel still unused, I got to work fiddling some more.  I replaced all the internal wiring on my speakers with it, and got more improvements of the same nature. Cool!

Next, things got silly.  I built myself a set of solid-core RCA interconnects - unshielded of course - and blow me down if these weren’t an improvement also.  Today, with the perspective of experience, I now know that all I did was replace the cheapest of cheap crap wiring with something just a little better.  But at the time all I knew was that there was a world of gain to be exploited by futzing around with cables.

One of the things I did was recognize that the purpose in life of my reel of solid-core cable was to provide mains wiring.  So I opened up all of my amplifiers and hand-soldered a length of solid-core to the appropriate terminals on the power supply’s transformer, and an approved power connector to the other end (in those days there were no IEC sockets - all electronics came with a hard-wired power cord).  Voila, my first custom power cord.  I’ll be honest with you and admit that my objective here was tinkering for tinkering’s sake, so I really was quite emphatically blown away when the solid-core power cord appeared to sound massively better than the stock power cord.

I scratched my head quite a lot over this finding, and because of all the work involved in soldering and disassembling, it was far from straightforward to do repeated AB comparison tests.  My solution was rather typical for a twenty-something.  I wired the original mains cord in parallel with the new solid-core one.  It was a few seconds work to unplug one and plug in the other (and if you plugged both in simultaneously during the switchover you didn’t need to power down the amp), the only downside being a couple of live 240V terminals lying idly around!  I now had a system where I could AB demonstrate the truly massive sonic differences between two different power cords.  Quite a few people came to hear the demo, and nobody failed to be convinced.  Many of them were not even audiophiles.  Interestingly, it strikes me just as I write this, that I never thought to listen seriously to BOTH power cords plugged in at the same time.

Thus it was that I became a power cord believer long before it ever became fashionable, and certainly many years before I ever saw a third-party power cord offered for sale in my local HiFi store.

In 1988 I moved to Canada.  My Naim 250 power amp and the solid-core built-in cable that I attached to it did not survive the relocation, and I found myself using a Jolida SJ502A tube-based integrated amplifier (with an IEC socket) and a stock Belden power cord.  Since I had the fortunate opportunity to build my own house, I was able to specify a dedicated music room.  It had reinforced floors, and a double-layer of gyproc on the walls [I might have done that differently if I was doing it again, but there you go].  Motivated by my experience with my solid-core power cords, I also took the opportunity to install a dedicated wiring spur that would power my music system.  It used the same 60A wiring that the electrician brought with him to power my 12kW electric furnace (although the furnace used three strands where my music system used just one).  A couple of years later I added some “hospital grade” wall sockets with a seriously beefy internal construction.  To this day, I remain quite happy with my audio system’s power infrastructure.

Over the years I continued to experiment with home-built power cords.  The trouble was, I never had any design basis to work from.  I never had any theory of power cables to guide me.  If I was going to build a better power cord, I had no clue what characteristics it would need to have.  So for many years I knocked together occasional cords based on scraps of unusual cables I came across from time to time.  I still have some of them.  None of my experimental power cords ever made any sort of noticeable improvement over the Belden cord.  A friend gave me an experimental power cord that he made, and that did sound slightly better, but I never heard anything to approach the magnitude of my original solid-core upgrade.  Strangely enough, I never considered building another solid-core power cord.

Not so long ago, I had an e-mail exchange with a fellow with a lot more expertise than me, and he suggested a design approach I had not thought of before.  His approach was based on RF.  Imagine, he said, that RF interference coming down the power cord is like someone try to soak you with a hosepipe.  You can try holding up a dustbin lid, and it will block the worst of it, but eventually you will still find yourself standing in a puddle of water.  What you want to do is to direct it back the way it came in a controlled manner.  According to my correspondent, most electronics contain a RF filter built into their IEC inputs.  These filters don’t actually filter out the RF, rather they function by directing it back the way it came.  Most power cords, he reasoned, are not good transmitters of RF, and a lot of the reflected RF ends up being “puddled” inside the equipment.  He held firm to the view that a good power cord would actually **TRANSMIT** the RF rather efficiently.

Bearing that in mind, I was able to source a few meters of a special RF cable designed to deliver prodigious amounts of RF power to the antennae of a transmitting tower.  As it happens, this cable comprises a single 1mm diameter solid core, beefy enough to be able to carry 15A and more, and so I could see myself using it to construct a power cord.  The power cord would comprise two of those cables in parallel, one core for the “live” and one for the “neutral”, with a separate copper line for the ground.  The shielding of the RF cables would also be connected to the copper ground at the plug end.

I have since built quite a few of those cables.  They are monstrously unwieldy.  The RF power cable bends, but only reluctantly.  To use, you must very carefully bend it into the right shape before you try to install it.  If you take one and straighten it out, and plug it into a high quality wall socket, it will stand there - one meter long - sticking out of the wall!  You really need a socket that is man enough to grip it, otherwise it can pop right out.  Also, you need to use it with equipment weighing at least 1kg, otherwise the power cord can lift it up into the air!  But in the right system they sound tremendous, with weight, power, spatial detail and tonal precision.  I have had specialty mains power cords come through my system priced well into 4 figures each, and my own cables are every bit a match for them.

For a while we sold these cables as “BitPerfect Digital Precision” power cords, but they are way too unwieldy for most people, and the market is just too small to make it worthwhile.  So we don’t sell them any more.  But, for the first time, I now have at least one design approach for power cords that seems able to prove itself out.  Without doubt there are many more waiting to be found.