"Arfa Daily" hath wroth:
I know that there is always furious debate on the audio groups about this,
but in all the years that I have been mending this stuff, I have never
actually been faced directly with it ...
Wrong class of customer. Such things tend to be purchased by people
with more money than technical abilities. Did you notice that the
cord is rather stiff? That's intentional as no self respecting
audiophile would hide such an expensive purchase behind their
equipment. It's made to be hung out the front of the rack or shelf,
where all can admire it.
Yesterday, a boat-anchor Yammy turned up from one of the high-end dealers
that I do work for, and with it was a power cable that the owner wants
fitting in place of the one that Yamaha saw fit to put on when they designed
it. This cable comprises a couple of metres of (20A?) three core rubber
power cable (the sort of stuff that you would use as the flexible 'tail' to
go from a wall plate to a storage heater, or maybe a hot water immersion
heater) plus a very ordinary UK 13A power plug on one end, and a reasonable
quality IEC straight plug on the other. The cost of this lead ? 100 UKP.
That's about $190 at the current exchange rate !! And he now wants to pay
the store to get me to fit it.
Ouch. One of these cables perhaps?
http://www.audioadvisor.com/products.asp?dept=25&view_all=true
Be sure to check out the $1,080 power cable.
There was an article in EDN on the topic a while back. Digging...
"OFC madness: Facts, not fantasy, regarding power cables for high-end
audio equipment."
http://www.edn.com/article/CA6418215.html
Now I'm actually not very happy about modifying anything to do with hot-side
power wiring, for obvious legal reasons, but my real question is about the
number of wires. Originally, the amp is fed with a standard 2 core power
lead. When this three core lead is fitted in its place, should I connect the
earth lead to the metal chassis ?
If it was 2 wire, it would need to be double insulated. Grounding the
chassis is always a good thing (unless it's a 40 year old AC-DC power
supply). Yeah, I would ground it.
I can't see that this should lead to any
potential safety issues, but as the amp was originally designed not to have
a power ground connected, might not connecting one lead to *more*
power-conducted noise getting in, actually making the performance *worse*
than the owner thinks that he is going to achieve, by his dubious mods ?
Only if the AC power line noise were fairly high level (several volts)
and the power supply design was relying on the common mode rejection
of the AC power cord to remove the noise. A rather crude power line
noise filter will remove all of that.
I have a contact within Yammy, who has direct access to the design boys back
in Japan, so I think that I am going to give him a call anyway, but I would
value the opinions of others on here as well.
Don't give them any ideas, or we may be plagued with $200 replacement
power cords.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558