Who needs Mains Cables?

Good question...

Many electric devices actually specify the power supply rejection ratio (PSRR) as part of the datasheet.

Most modern electronic devices start with AC, then rectify and filter it using a bridge rectifier into a somewhat noisy DC, but then filter that out to a relatively clean DC using voltage regulators -- most noise/ripple on the AC line will be eliminated by this process. Moreover, most audio-grade opamps will usually have 80-110dB power supply rejection ratios within the DC-20kHz audible frequency range anyway, so even if there is low-level noise on the DC rail after the AC -> DC conversion process, this shouldn't affect the sound quality if the amplifier is well-designed.

If there really are massive problems in your AC (eg big voltage spikes or dropouts), I'd recommend either an isolation transfomer, or simply running your audio equipment off of car batteries -- ensuring total isolation between your audio equipment and the noise on the line. Running from batteries is often done in electronics labs to prevent crosstalk/interference between high-voltage devices and extremely sensitive devices.

In the 90s when I was much more easily impressed than I am today I had a mains cable made up by a guy who was experienced in this field. He was very nice and I was sure the cable was bringing benefits to my system.

Today I still have that special cable and it is absolutely obvious to me that it makes no difference whatsoever.

The power of auto-suggestion is very much at work with these cable "upgrades" of various sorts.

Jason Serinus "upgrades" every mains cable in a high resolution system with the extremely expensive Nordost Valhalla and performs blind ABX tests. No difference is detectable.

Article is here.

Interesting video and insight on the matter, power cables are at the top of the snake oil nonsense, the current coming out of your main travels for miles in underground cables you can't even see, then tiny 2-3 mm thick wires distribute the power in your apartment, how can the last meter the power goes thru possibly affect the sound ?

Not to mention that the inner wiring from from the IEC plug to the boards on your amp are unlikely to be anything special...

I don't get the 'there are miles of cables before the amp' argument. Most amps have an AC power supply, so the amp is also the first as well as the last part of the chain.

What Hifi did a blind test (in their magazine, there is no on line link) where the subjects thought that the components were being changed. instead the cables were being changed. The biggest (relatively speaking) was adding mains conditioning.

I would recommend mains conditioning, though it does not work all of the time. I do not believe power cables work at all.

Quote:

Originally Posted by Prog Rock Man 

I would recommend mains conditioning, though it does not work all of the time. I do not believe power cables work at all.

Mains conditioning is something I am quite interested in investigating.

I know that voodoo power cables don't work because I've been there and done that.

Different means of mains conditioning have existed long before the voodoo crowd came along with their silly cables, and I think that the mains conditioners might have suffered a bit in reputation (as has the whole of the hi fi industry) from the voodoo people.

Well, after those few seconds a mains cable would be useful. Or?

Quote:

Originally Posted by krmathis 

Well, after those few seconds a mains cable would be useful. Or?

Pedal power?

Quote:

Originally Posted by Prog Rock Man 

I would recommend mains conditioning, though it does not work all of the time. I do not believe power cables work at all.

I would recommend line conditioners as well.  I don't how much (if any) difference they make to SQ, but the protection is undeniable.  My current residence has relativly clean power and underground line, but you can never be to careful.  Forty pound toroidals and beer can sized caps eat a lot of noise and stop spikes from frying all your gear.  They're good for pretty much anything short of direct lightning strike.

Cheap used models are all over ebay.  Shipping can be killer, so try for a local pick up if possible.

Quote:

Originally Posted by googleborg 

you could even get two hefty motors/dynamos and use one to spin the other and regenerate perfect 240v 50Hz mains from that, with total isolation

Years ago I had thought that this would be a good thing to design and put into production but never got around to it.

The plan was that the motor would drive the dynamo via a belt driven flywheel. The belt driven flywheel would be a big plastic thing which could be filled with sand, or lead shot, to make it very very heavy and thus give a stable isolated 240v 50Hz supply.

Quote:

Originally Posted by p a t r i c k 

Years ago I had thought that this would be a good thing to design and put into production but never got around to it.

 

The plan was that the motor would drive the dynamo via a belt driven flywheel. The belt driven flywheel would be a big plastic thing which could be filled with sand, or lead shot, to make it very very heavy and thus give a stable isolated 240v 50Hz supply.

You are just stacking inefficiencies there.  Maybe for a headphone rig you could use something like that without sending your power bill through the roof.  I picturing less than 20% efficiency if used with a class A amp.  That's not counting the speakers either.  With particularly inefficient speakers I could see less than .1% overall efficiency.

Better to stick with batteries and an inverter.  Then again price or value never dictated anything in this market...

Quote:

Originally Posted by maverickronin 

Better to stick with batteries and an inverter.  Then again price or value never dictated anything in this market...

Yes I agree with you, on both points