Power Cords
 

"David Lodge" wrote in message
ps.com...
Trevor Wilson wrote:
I use an amplifier which has no speaker relay protection systems.
Therefore,
when it is unplugged, it can still deliver power to the speakers, for as
long as the main capacitor banks can supply it. The main filter caps
total
250,000uF. This means the amplifier can deliver a handful of Watts for
several seconds. Plugging and unplugging the amp from the 240VAC mains
supply is inaudible to all listeners. Therefore, there can never be any
difference between power cords.

Is there not another angle to look at (says he throwing fuel on the
cynical fire...) and that is when the mains power supply is noisey.

**Sure. However, a power cord is not even going to appraoch the capabilities
of a decent power supply, in removing mains bourne crap.

While I can appreciate a mains cable ain't going to make any difference
with a clean power supply, to what extent do these noise reducing mains
cables with their ferrite rings and platted cables reduce an
interference that may be inherent in the supply?

**All of which can easily be placed inside the amplifier, if there is a
problem. Moving this hardware to the outside is wasteful, inefficient and
costly.

Of course an amp that
removes all such interference before the amp power lines will not show
any difference, but will a hifi component with a less than optimally
design power supply benefit from a "noise reducing" cable?

**Perhaps. Ironically, cheap, crappy amplifiers (i.e.: The ones which suffer
from mains borne noise) are not likely to be used with expensive power
cords.


--
Trevor Wilson
www.rageaudio.com.au

Power Cords
 

In article ,
Luke Siemaszko wrote:
So how does a kettle get on then pulling the power it takes?, and I've
never had a problem with an actual kettle connector....

Kettle draws loads of power
some is wasted in voltage drop over crap connector
connector gets slightly warm
you don't notice
life continues

there aren't (as far as I know) hordes of kettle enthusiats eager to
squeeze every last drop of performance from their kettles. Amplfifiers,
thoough, operate in a different environemnt to kettles.....

A kettle draws continuous power at around 2 kW. Domestic amps don't draw
anywhere near at *peak* 2kW. That's 2000 watts. And then they convert that
AC to DC and use large reservoir capacitors. Of course you might have a
2000 watt amplifier but I somehow doubt it.

--
*Everyone has a photographic memory. Some just don't have film.

Dave Plowman London SW
To e-mail, change noise into sound.

Power Cords
 

"Dave Plowman (News)" wrote in message
...
In article ,
Luke Siemaszko wrote:
So how does a kettle get on then pulling the power it takes?, and I've
never had a problem with an actual kettle connector....

Kettle draws loads of power
some is wasted in voltage drop over crap connector
connector gets slightly warm
you don't notice
life continues

there aren't (as far as I know) hordes of kettle enthusiats eager to
squeeze every last drop of performance from their kettles. Amplfifiers,
thoough, operate in a different environemnt to kettles.....

A kettle draws continuous power at around 2 kW. Domestic amps don't draw
anywhere near at *peak* 2kW. That's 2000 watts. And then they convert that
AC to DC and use large reservoir capacitors. Of course you might have a
2000 watt amplifier but I somehow doubt it.

**I've worked on a few, but they are few and far between. Significantly,
most alleged Class A amps aren't, simply because US mains supply systems are
hopeless. Anything more than a kW from a US power point is pretty much
hopeful thinking. Krell learned this lesson after their early amps (KSA100,
KMA200, et al) weren't able to deliver the goods, due to typical US power
points. They sensibly switched to Class A/B (albeit with lots of bias
current), so the things could actually work properly in their country of
origin.



--
Trevor Wilson
www.rageaudio.com.au

Power Cords
 

In article om, David
Lodge wrote:


Is there not another angle to look at (says he throwing fuel on the
cynical fire...) and that is when the mains power supply is noisey.

This is why amplifier designers tend to pay attention to ensuring the amp
has a decent PSU, and has some level of inherent noise rejection. They also
live in the real world. Indeed, the mains supply in many factories or labs
can be even worse than domestic mains in terms of the interference added to
the basic mains waveforms.

While I can appreciate a mains cable ain't going to make any difference
with a clean power supply, to what extent do these noise reducing mains
cables with their ferrite rings and platted cables reduce an
interference that may be inherent in the supply?

Depends. Those that have 'ferrite coatings' would be likely to have almost
no effect on anything except the seller's bank balance. Correct use of
rings, etc, may help in some cases, but this isn't "mains cables" any more.
We are moving into the different topic of "mains filters".


Of course an amp that removes all such interference before the amp power
lines will not show any difference, but will a hifi component with a
less than optimally design power supply benefit from a "noise reducing"
cable?

If the amp and its PSU let through interference, then a filter can help.

FWIW my experience is that some items do produce audible 'clicks' at times
which are mains injected. Reason follows from the above: PSU and rail
rejection not adequate. This can be dealt with by using a mains filter, not
an expensive mains cable. Alternatively, change the item for something else
that has a better PSU and/or amp stages with better rail rejection.

Above said, my experience is also that most items I've used don't have this
problem - or at least it became rarer some decades ago as the designs and
components improved.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

Power Cords
 

"Dave Plowman (News)" wrote in message
...
In article ,
Luke Siemaszko wrote:
So how does a kettle get on then pulling the power it takes?, and I've
never had a problem with an actual kettle connector....

Kettle draws loads of power
some is wasted in voltage drop over crap connector
connector gets slightly warm
you don't notice
life continues

there aren't (as far as I know) hordes of kettle enthusiats eager to
squeeze every last drop of performance from their kettles. Amplfifiers,
thoough, operate in a different environemnt to kettles.....

A kettle draws continuous power at around 2 kW. Domestic amps don't draw
anywhere near at *peak* 2kW. That's 2000 watts. And then they convert that
AC to DC and use large reservoir capacitors. Of course you might have a
2000 watt amplifier but I somehow doubt it.

--
*Everyone has a photographic memory. Some just don't have film.

Dave Plowman London SW
To e-mail, change noise into sound.

Don't doubt. Just a quote from my ss NRG manual Model A201S:
Power consumption: Maximum for each respective load
Idle (No Load) 1.3kW
8 Ohm 1.3kW
4 Ohm 1.65kW
2 Ohm 3.3kW
1 Ohm 6.4kW
The actual values will typically be lower with 'normal' music, though I
could have been a deaf headbanger with a pair of 1 ohm Apogee Scintilla ;-)
I'm sure some of the larger Krells spec much the same. Its fun/agonizing
watching the digits on the consumer unit whizz around on something like the
S/Saens Organ symphony. Thats exactly why the supply cable is hard wired
rather than trusting to an iec connector.

-=Mike=-

Power Cords
 

In article ,
Mike Gilmour wrote:
Of course you might have a
2000 watt amplifier but I somehow doubt it.

Don't doubt. Just a quote from my ss NRG manual Model A201S: Power
consumption: Maximum for each respective load
Idle (No Load) 1.3kW
8 Ohm
1.3kW
4 Ohm 1.65kW
2 Ohm 3.3kW
1 Ohm 6.4kW


The actual values will typically be lower with 'normal' music, though I
could have been a deaf headbanger with a pair of 1 ohm Apogee Scintilla
;-) I'm sure some of the larger Krells spec much the same. Its
fun/agonizing watching the digits on the consumer unit whizz around on
something like the S/Saens Organ symphony. Thats exactly why the supply
cable is hard wired rather than trusting to an iec connector.

At 26 amps you're into needing a 32 amp radial wired in 4mm.

Is it really worth it? ;-)

--
*If you're not part of the solution, you're part of the precipitate *

Dave Plowman London SW
To e-mail, change noise into sound.

Power Cords
 

Jim Lesurf wrote:
FWIW my experience is that some items do produce audible 'clicks' at times
which are mains injected. Reason follows from the above: PSU and rail
rejection not adequate. This can be dealt with by using a mains filter, not
an expensive mains cable. Alternatively, change the item for something else
that has a better PSU and/or amp stages with better rail rejection.

That all make sense (both what I quoted above and what I didn't), so is
it fair to say:
- mains filtering devices can provide a degree of noise reduction, but
whether you'll hear a difference or benefit from it depends on the
level of noise in the first place, and the extent to which your amp (or
source component) filters out the noise anyway
- Good main cables themselves are likely to provide a benefit only if
they replace a cable which is difficient in delivering the required
power. Once its sufficient (as I suspect most standard cables are),
there's no additional benefit to be gained by replacing them with
"better" cables.

Power Cords
 

"Luke Siemaszko" wrote in
message

tony sayer wrote:


So how does a kettle get on then pulling the power it
takes?, and I've never had a problem with an actual
kettle connector....

Ditto for space heaters, etc.

Kettle draws loads of power

Most kettles are relatively low-powered compared to the
appliances that are heavy-hitters.

some is wasted in voltage drop over crap connector
connector gets slightly warm
you don't notice
life continues

there aren't (as far as I know) hordes of kettle
enthusiats eager to squeeze every last drop of
performance from their kettles.

In the US self-heated kettles are far from the largest
single users of power. Electric space heaters are near or at
the top.


Amplfifiers, thoough, operate in a different environemnt
to kettles.....

Yes, resistive loads just sit there and suck power at a high
rate, while the average drain from an audio power amp is
pretty low.

Power Cords
 

"Jim Lesurf" wrote in message

In article
om,
David Lodge wrote:


Is there not another angle to look at (says he throwing
fuel on the cynical fire...) and that is when the mains
power supply is noisey.

This is why amplifier designers tend to pay attention to
ensuring the amp has a decent PSU, and has some level of
inherent noise rejection. They also live in the real
world. Indeed, the mains supply in many factories or labs
can be even worse than domestic mains in terms of the
interference added to the basic mains waveforms.

While I can appreciate a mains cable ain't going to make
any difference with a clean power supply, to what extent
do these noise reducing mains cables with their ferrite
rings and platted cables reduce an interference that may
be inherent in the supply?

The biggest EMI filter in most power supplies is the power
transformer. If its optimized for efficiency at 60 Hz, its
likely to be a good rejector of higher frequencies.

Power Cords
 

"Dave Plowman (News)" wrote in message
...
In article ,
Mike Gilmour wrote:
Of course you might have a
2000 watt amplifier but I somehow doubt it.

Don't doubt. Just a quote from my ss NRG manual Model A201S: Power
consumption: Maximum for each respective load
Idle (No Load) 1.3kW
8 Ohm
1.3kW
4 Ohm 1.65kW
2 Ohm 3.3kW
1 Ohm 6.4kW


The actual values will typically be lower with 'normal' music, though I
could have been a deaf headbanger with a pair of 1 ohm Apogee Scintilla
;-) I'm sure some of the larger Krells spec much the same. Its
fun/agonizing watching the digits on the consumer unit whizz around on
something like the S/Saens Organ symphony. Thats exactly why the supply
cable is hard wired rather than trusting to an iec connector.

At 26 amps you're into needing a 32 amp radial wired in 4mm.

Is it really worth it? ;-)

Oh yes... :-))


--
*If you're not part of the solution, you're part of the precipitate *

Dave Plowman London SW
To e-mail, change noise into sound.