Arfa Daily wrote in message
...
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 ...
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.
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 ? 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 ?
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.
Arfa
If the user-accessible part of the chassis is metal then that has to be
bonded to mains earth.
2 core is only allowed for double insulated kit in the UK.
Its not a quality of sound issue but a health and safety issue first and
foremost.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/