I have recently had the fortune that my Flat was re-wired to high standards (without cost to me) and that indeed made an impact on overall sound Quality.
It resulted in me applying some more attention to the subject of Mains and HiFi-Equipment.

Now mains-cables in HiFi are a long-standing "Cable of Contention". The most often heard argument against the use of special Mains-Cables is that they cannot possibly make a difference after all these miles of lousy cable all the way from the power-station.
And as usual, this is as much true as it is untrue. The long lines are not that long (what matters is the Cable to the Transformer feeding your house). In addition, much of the effects mains-cables have can be traced back to RFI and noise-loops.
There the important part is the mains-cable from the unit to distribution block, exactly the mains-cable as we call it. I suggest reading : http://www.sstage.com/articles/pete01.htm for an overview that includes the effects of interconnects and mains on Sound based on purely scientific and demonstrable principles.
Somewhat tied in with this is RFI Pickup by the Mains as well as pollution by various domestic and industrial appliances. Most of the Pickup will happen inside the house as the buried (underground) cable is usually armored and hence shielded.... The intervening transformer-stations should eliminate or at least severely attenuate any RF picked up by the national Grid.

Another factor is impedance. By using reasonably large Diameter this can be addressed to a point. The usual modern Cable leading to the consumer-unit is massive (> 6mm^2), so up to the same diameter cable could be (should be) used for the Mains-Ring cable.
However many of us are stuck with ordinary Mains and are not able to change these. So other means and methods are needed. I have developed a set of highly effective and simple to make Mains-Condition units. Unlike most mains-conditioners they work only on a shunt-basis.
My highly modded Marantz CD-67 SE Player however was helped along notably by using suitable Mains-cables and conditioning, as was the modded Marantz Poweramp I still have around. The Edison 60 Kit Valve Amplifier (in Triode PSE Mode) also improved quite nicely with one of the cables discussed below.

The largest (and fairly reliably detectable in a blind test) improvement came when I replaced the about 2.5m between my Extension socket-block (Metal, Shielded - intended for use in 19" Racks for Computers) and the Wall Socket.
It had before been flexible multistranded around 16-Gauge (1mm^2) three Core stuff.
Using my "UBYTE-M" Mains-Cables (UBYTE stands for "Usually Beats Your Terrible Engineering") and my "Superstealth Megamanga Mains Line Ultracleaners (R)" offer a jump up in Sound-Quality much greater for example than replacing standard Mains-Cabling with Kimber (also a Socket Extension using Kimber Mains-Cable).
One thing to note however is the fact that I live in England where we have twice the Voltage and half the current in the Mains when compared with the US. I'd expect that to reduce the Effect of the Mains-Cable very literally by 6db.
So with the US Mains there may be a larger Difference.
All necessary parts for these Mains-Cables and tweaks can be readily and cheaply obtained from Maplin Electronics.
The Materials to make a 1m UBYTE-M Mains-Cable are around 6 UK Pound for the Low-Current (6A or less) Version and the Mains-Clarifiers are build into "Wall-Wart" Style PSU Boxes with a total cost of under 15 UK Pound.
Details follow below, but first:

Safety Note on Mains-cables and other mains connected Tweaks:

If you are not comfortable working with Mains-Voltages - LEAVE IT ALONE!!!

Remember to have the Cables and Units TESTED BY A QUALIFIED ELECTRICIAN for electrical Safety.

Make double and triple sure that there are no Damages to the Insulation or anything of that type. Observe the Safety-Regulations and Grounding as applicable IN YOUR COUNTRY.

If you make and use such a mains-cables or Filters it entirely YOUR responsibility to ensure the Electrical and Fire Safety.

The Author and TNT-Audio will NOT accept ANY liability for any form of Damage incurred to Live, Health or Property.

My Mains-Cable construction for the "UBYTE-M" () is not that different from some of the Mains-cables Synergistic Research sells. The Cable I use is made from two length of Coax, having a 16-14 Gauge Solid Copper Core, a aircell polyethylene Insulation, and a copper foil & braid shielding.
The specific Cable I use is sold as "Low-Loss Satellite" Cable or called "CATV" Cable. The specific Partnumber in the RS Components, Farnell and Maplin Catalogue is either CT-125 or FT-125. It has a Copper Foil & Braid Shield and a 1.25mm solid copper Center conductor. The Outer Diameter is around 7mm.
We have also made cables of similar Design from the much heavier RG-213/U Coax, a Coax with 7 X 0.75mm copper center and braided shield. This Cable has about 10mm Diameter.
I would recommend to fuse mains leads based on the CT-125 with 6 Ampere' or less (though even 13A should still be safe), while the RG-213 based Leads can be safely used up to 20A and above.
To continue with the construction, the two parallel length of Coax are held together by expandable Nylon sleeving. This is available in various Diameters and gray or black from the usual large Electronic Suppliers. You can find it usually in the same sections as heatshrink sleeving and other such accessories.

One Center-Conductor is used as Live, the other Neutral. Both shields are tied to Earth. The Plugs fitted are best of decent quality and may require some mechanical modification to allow the really "fat" Cable to be fitted.

These Cables are cheap, safe and work, they have the "Audiophile approved Matcho Cable" look, so I think I'll stick with them.
They have been bettered by much more exotic constructions using Teflon, Silver-Wire and complex Geometry's, but even these Cables are not hugely better.
I have also been working a lot on Mains-Filtering lately and got some rather nice results. I use a "supercharged" Version of the Audioprism "Quiet Line" Filters. I called this in a whim the:

"Thunderstone Audio Superstealth Megamanga Mains Line Ultracleaners ®".

Before starting to make one of these PLEASE REMEMBER THAT MAINS-VOLTAGES CAN KILL. Be careful and make sure you understand how to make such pieces of work as described below electrically safe.
Maplin sells a large Plugtop PSU Case. The Order-Code is FG41U, costing 3.49 UK Pound.
Maplin also sells "mains-rated" 500V AC Capacitors, we need the 100n Units, two per Filter-Plug. For these Capacitors the Order-Code is FA21X with a cost of 1.73 UK Pounds each.
We also need one of the Motor-run Capacitors of the 250V AC 8uF Variety. This has the Order-Code DS97F and costs 3.71 UK Pound.
In addition we need four 1Mega-Ohm High Voltage Resistors. These cost 37 Pence each and have the Order-Code V1M .
I also recommend at least one "MOV" Spike suppresser (275V). With a cost of 78 pence and the Order-Code CP76H this brings our total bill of materials to a grandiose 12.92 UK Pound.

Finally a tweak that not only works but also has a longer name than pricetag, instead of the other way around!
The "Plug-In" Nature of these Filters allows for quick A/B comparisons, trying different locations in the Electric Circuit and they can be plugged into the Mains near to a noise-generating appliance to quite it down.
However, it is possible to use a isolated Box (beware of using well isolating materials that are fire-safe) to house the components in the trailing lead for Socket Extensions. This scheme also works extremely well.
The whole collection of parts is connected up rather simply....

The Plastic "Groundpin" is replaced by a real metal one.
I use the MOV directly across L & N (Live & Neural) as well as one of the 100 nF Capacitors. A Pair of the 1MegaOhm Resistors is also connected here. These Resistors will discharge the Capacitors in the Plug if it removed while there is Mains-Voltage present while the Plug is being removed.
The other 100 nF Capacitor goes between N & Earth. Again a pair of the 1M Resistors is fitted in parallel for safety purposes. All of this is directly soldered to the Plugs Pin's, with the leads kept as short as possible and isolated where they are need to left long....
Then the 8uF Capacitor is connected with short, isolated solid core mains cable to the L & N Pins.... Close the Plug.... Finished.

One warning though.... Never plug the Plug into a live outlet. Switch the power to the outlet off first, then plug the Filter in. Under certain condition plugging the thing in while the outlet is live can result in spectacular Sparks being drawn by the inrush current of the 8uF Capacitor....
This is in no way dangerous or anything, but can be quite frightening.... As said before, these Plugtop Units can be used pretty much everywhere. I have one on the same outlet as the Fridge, one plugged into my Audio-System and another one into the Socket Extenuation for my TV/Video System.
Again, please see the Safety-notes included above and make sure you follow them. It's your life and that of your loved ones - not mine....

© Copyright 1998 Thorsten Loesch and TNT-Audio