Cheap powerstrip, DIY high-end cable

[w00t]

Hi everyone!

I was thinking if I could get a cheap powerstrip (saw one for SGD10, which is around USD5) and change its cable to a shielded one.

I will either plug in a powerfilter into one of the sockets or implement it into the strip. What do you guys think?

Cheers!

[bremen nacht]

Why shielded cable? There are dozens of metres of unshielded cable between the wall socket and the meter - and then hundreds of metres to the substation. I don't see how shielding the last couple of metres is going to achieve anything.

The best place for filters is inside each component. Try replacing your IEC connectors with something like this: http://www.farnell.com/datasheets/44953.pdf (warning: 8MB PDF)

[AGGEMAM]

Originally posted by bremen nacht
Why shielded cable? There are dozens of metres of unshielded cable between the wall socket and the meter - and then hundreds of metres to the substation. I don't see how shielding the last couple of metres is going to achieve anything.

Well actually it does make a difference, not because of the power supply becoming any cleaner, but the electromagnetic radiation of the power chords having less influence on the signal cables.

[SimontY]

Hi w00t,

I'll tell you what I did to mine, hopefully it will give you some ideas...

I had a 'top of the range' 8-way Belkin, which was ok, but I decided to modify it after receiving advice suggesting Belkin strips degrade sonics, and I didn't want to fork out for an audiophile-price power block! (also I didn't believe the Belkin could be so bad)

Firstly, I had to modify a screwdriver just to open her up, using a Dremel When inside I one can quickly see why these things make a difference- this Belkin had a PCB with 6 varistors, a very small 'x' cap acroos L+N - this is the good part. The bad part is power goes through (quite thick) PCB tracks, and a fuse! Yes, as well as the fuse in the plug! The rail connector things were all tarnished and horrid too.

I polished the rail things with brasso, and cut out the PCB, removing its components for later use, I just bypassed anything that used to be inside, wiring the rail things directly.
-The impovement was shocking, as I expected none to little, but the increase in dynamics and solidity, particularly in bass was excellent. I attribute this mostly to there being a silly 0.5R fuse in the path.

Later, I removed the wire, as I was using an extension to reach it. So I replaced it all with a long piece of hand braided (very) high current wire. Again, an increase in solidity and dynamics was had, and distortion went down, and the noise floor etc all seemed to improve too.

AFAIK shielding can offer no improvement to a power cable, shielding is often said to do more harm than good in most cables/wires.

BTW, you probably do want varistors and caps across the mains, I had little use for mine as I made a box with a large 'lighting' cap (10uf) across live and neutral, y caps to earth, and 2 varistors, and a cool light at the front This box seems to make the sound warm and pleasant with other small improvements.

edit: don't forget to polish all your plug pins with brasso and then protect and 'enhance' them with contact enhancer such as Deoxit - more improvement (you'll start to know what clean, deep bass is, hehe). Also, spray the box black as I did!

[bremen nacht]

Simon, that's a lot of unexpected improvement.

What components did you have plugged into the powerstrip? Do you have any theories about how your mods improved the sound?

I am agnostic on the subject of how mains supplies can affect sound. I suspect that stuff like half an ohm's worth of fuse in the mains has little or no effect as the transformer/capacitors in an amp provide a low impedance for the amp's circuitry. I don't understand how high current wire can improve bass - a 100W amplifier is only going to take a couple of amps at most from 240V.

Not disputing your perceived improvements, I'd just like to understand the mechanics of what's happening.

I will try 10uF across the mains, that sounds like worthwhile filtering.

[SimontY]

Originally posted by bremen nacht
Simon, that's a lot of unexpected improvement.

What components did you have plugged into the powerstrip? Do you have any theories about how your mods improved the sound?

Hi Bremen,

I cannot explain why there is this [marked] change in sonics, as I am not an EE, and cannot backup any of this with facts or science, or even blind listening, and so I expect some skepticism, especially as many have not 'played' with the mains yet, so cannot corroborate.

As for why I think it improves the sound: I could be way off the mark, but I think it's mainly down to resistance. It could also be something to do with RFI, this is why I braid wires. I think dodgy contacts pickup RFI too, perhaps partly why cleaning and applying Deoxit is so beneficial. WRT "0.5ohm fuse" - it was the fuse, cleaner contacts all-round, *and* no PCB ie. more than 0.5ohms total.

I openly admit I may have imagined these improvements, or that the improvements could be due to some unknown factors, though these were quite large changes to imagine. They do correlate with what Russ Andrews says about mains quality, and this suggestive information, combined with my furtive imagination might explain it as entirely ficticious. There, that covers my back, now I needn't explain, haha!

[w00t]

Wow, amazing improvements! Good thing I have 13 Rifa X2 caps coming my way now.

I have some Belden 8719 with me currently. The wire seems thicker than what I currently have for the Hi Fi mains strip.

[SimontY]

Originally posted by w00t
Wow, amazing improvements! Good thing I have 13 Rifa X2 caps coming my way now.

Indeed! ...and I'm sure I needn't remind you to use a bleed resistor on those little babies, so you don't accidentally kill yourself!

[tiroth]

Just remember that the smaller value caps are more effective at filtering HF noise than the larger value ones. They also produce less leakage current.

The optimum is probably some combination of small and large suppression caps.

Edit: typo fixed. Sorry!

[SimontY]

Originally posted by tiroth
Just remember that the smaller value caps are more effective at filtering HF noise than the lower value ones.

Hi,

My totally unscientific mind tells me a mix must be best. I have about 5 0.47uf x caps in a bag somewhere, I'll see if throwing those in my filter makes any additional change. Also have a couple more 'y' rated caps that can go in.

I was going to put these in my isolation transformer, for my amp, but I'm too scared of it, ever since it 'rejected' the varistor I tried, lol.