Cables -- some questions to ponder -- power cords
Raymond Makul
[ Although this has the potential for a contentious exchange (if form
holds), the poster asks a very legitimate question. -- jwd ]
For those who are great believers that various kinds of cables can
have significant differences on the performance of their systems, I
ask the following:
I see "hospital grade" replacement power cords that sell for prices in
the $200 range. But they plug into a household wall socket, that in
turn is connected by plain household wiring to a circuit breaker box,
when then goes through meter to my utility service drop, to my power
company's line and line transformer. How does "improving" the power
cord make any significant difference if it is still connected to my
crappy house wiring, and everything else upstream of it? Or should I
rewire my house with "oxygen free" copper wiring, and ask my power
company to install an "oxygen free" service drop and line transformer?
Somehow, I could see value of filtering the power going into my stereo
to remove line noise, harmonics, etc., but for the life of my I can't
figure out what the supposed difference the power cord would make if
it replaces one of adequate current carrying capability.
--
Raymond Makul
al...@bellatlantic.net
Charlie Hand
In article <5ah0ue$2...@eyrie.graphics.cornell.edu>,
Raymond Makul <al...@bellatlantic.net> wrote:
>[ Although this has the potential for a contentious exchange (if form
> holds), the poster asks a very legitimate question. -- jwd ]
>For those who are great believers that various kinds of cables can
>have significant differences on the performance of their systems, I
>ask the following:
>I see "hospital grade" replacement power cords that sell for prices in
>the $200 range. But they plug into a household wall socket, that in
>turn is connected by plain household wiring to a circuit breaker box,
>when then goes through meter to my utility service drop, to my power
>company's line and line transformer. How does "improving" the power
>cord make any significant difference if it is still connected to my
>crappy house wiring, and everything else upstream of it? Or should I
>rewire my house with "oxygen free" copper wiring, and ask my power
>company to install an "oxygen free" service drop and line transformer?
I suspect, though I'm not certain, the "hospital grade" may be mostly
about leakage current. When I designed equipment for use in surgical
rooms, there were all kinds of grounding and leakage requirements (you
wouldn't want a milliamp of leakage finding it's way to the patient's
heart!)
>Somehow, I could see value of filtering the power going into my stereo
>to remove line noise, harmonics, etc., but for the life of my I can't
>figure out what the supposed difference the power cord would make if
>it replaces one of adequate current carrying capability.
I only hope you applied for patents before posting this. Think of the
profits!
"Re-wire your entire house and community to experience night-and-day
improvement of sound stage and imaging!".
How about this: "Audiophile substation, only $1,500,000 per channel"!
-Charlie
--
--
/Newsgroups: .*,.*,.*,/h:j
rp...@netonecom.net
> How does "improving" the power cord make any significant difference
> if it is still connected to my crappy house wiring, and everything
> else upstream of it?
Oh yes I've asked that question too...
I've spent over $700 on three power cords last year... they work but
don't really know why either. Two years ago I hired an electrician
to installed a 20 amp service to the stereo which made no difference.
That same year I also installed a power conditioner and that made a
difference. If you read the advertising for power cords it appears
the manufactures have diverse reasons they work as well.
[ No offense intended to the poster, but this is the type of response
that gets us nowhere fast. Short of a statistically valid sampling
of the readership represented through such replies, simply saying "I
don't know why it works, but it does do for me" doesn't amount to
much at all. Given the level of expertise out there, we ought to be
able to deal more concretely with the matter. Anyone else want to
try? Apologies to Rich ... -- jwd ]
Best Regards,
Rich
Michau II
>I see "hospital grade" replacement power cords that sell >for prices
in the $200 range. But they plug into a >household wall socket, that
in turn is connected by plain >household wiring to a circuit breaker
box, when then goes >through meter to my utility service drop, to my
power cord make any significant >difference if it is still connected
to my >crappy house wiring, and everything else upstream of it?
I have no idea, I change my amp's 'factory' power cord to a Tara Lab's
PRISM and it makes no difference.
A while later I have to replace my pre-amp's power cord (I moved my
sofa and one of the sofa's leg landed on the power cord and ripped the
insulation so I have to replace it). I got a second hand power cord (a
Tara Affinity) and this time it made a big difference(!). Moved it to
the amp and it made a different as well. So I bought some more and the
system sounds better ever since.
I never thought power cables make differences beffore.
Michau
Curtis Leeds
Raymond Makul wrote:
> I see "hospital grade" replacement power cords that sell for prices in
> the $200 range. But they plug into a household wall socket, that in
> turn is connected by plain household wiring to a circuit breaker box,
> when then goes through meter to my utility service drop, to my power
> company's line and line transformer. How does "improving" the power
[ cut -- rgd ]
Obviously, if you have "crappy house wiring" and severe
electrical service deficiencies, improving the quality of an
electrical cord is not likely to produce any real improvement. And, of
course, your utility will laugh at you if you request OFC copper wire
at your service drop.
However, some audiophiles are fortunate to have sound
electrical wiring in their homes, and satisfactory electrical
service. In such cases, do you find it difficult to accept that a bad
electrical cord could be a "weak link"?
--
********************************************************
Curtis Leeds cle...@mail.idt.net
"A man hears what he wants to hear, and disregards
the rest."
********************************************************
James W. Durkin
Curtis Leeds <cle...@mail.idt.net> writes:
> Obviously, if you have "crappy house wiring" and severe electrical
> service deficiencies, improving the quality of an electrical cord is
> not likely to produce any real improvement. And, of course, your
> utility will laugh at you if you request OFC copper wire at your
> service drop.
> However, some audiophiles are fortunate to have sound electrical
> wiring in their homes, and satisfactory electrical service. In such
> cases, do you find it difficult to accept that a bad electrical cord
> could be a "weak link"?
Bad argument Curtis.
The stock power cord on many, if not most, pieces of high-end gear
appears to be of equivalent quality to anything upstream in the homes
of audiophiles with "sound electrical wiring in their homes, and
satisfactory electrical service". Given this, what does an audiophile
power cord buy you? If all you want is to make dead sure you're up to
the level of anything ahead of the electronics, you can put spec or
hospital grade plugs on the best three conductor power cable you can
find for all of about $20-25. What's lurking in the $200 certified
audiophile cable that is going to substantively better that?
Inquiring minds and all that root ....
--
James Durkin
j...@graphics.cornell.edu
Tim Brown
Raymond Makul wrote:
> I see "hospital grade" replacement power cords that sell for prices in
> the $200 range. But they plug into a household wall socket, that in
> turn is connected by plain household wiring to a circuit breaker box,
> when then goes through meter to my utility service drop, to my power
> company's line and line transformer. How does "improving" the power
> cord make any significant difference if it is still connected to my
> crappy house wiring, and everything else upstream of it?
Hospital grade cords have enhanced durability and quality control.
Unlike the wire in the walls line cords get flexed, stretched and
ocassionally abused. The connections between the wire proper and the
plug/socket ends is especially vulnerable. Don't know if this is still
true but hospital cords were required to have clear plugs so the
condition of the ground wire can be easily inspected. Hospital grade
cords do not perform any better electrically than "regular" line
cords. --
TB
email: brownt at ase.com
Tim Brown
Gary S. Bekkum
James W. Durkin wrote:
[snip -- moderator bt]
> What's lurking in the $200 certified
> audiophile cable that is going to substantively better that?
>
Do any of the high-end power cords use special shielding that would
reduce RF/EMI pickup or transmission? Consider that the power cords
in your equipment are closest to your audio system, and any leakage or
pickup of noise would be concentrated there. The house wiring would
run away from your home run area (although it might pick up noise from
other appliances and computers etc.) Any one else have thoughts on
this?
Gary
Fremantle Cockburn Enterprise Agency Inc
In article <5ajf7j$m...@tolstoy.lerc.nasa.gov>, Curtis Leeds
<cle...@mail.idt.net> wrote:
> Obviously, if you have "crappy house wiring" and severe electrical
> service deficiencies, improving the quality of an electrical cord is
> not likely to produce any real improvement.
For the purposes of general enlightenment, please define the variables
that constitute 'quality' in an electrical power supply cord, such
that "real improvements" might be made to the performance of one's
audio/video system other than, e.g., current carrying capability,
voltage drop per unit length, insulation, and possibly the contact and
corrosion capabilities of the plug/socket pins/receptacles!! I was
unaware that there were any other relevant factors besides UL/CSA,
VDO, IEC, or other standard specifications, but having an open mind
I'm willing to hear about new ones!!
> And, of course, your utility will laugh at you if you request OFC
> copper wire at your service drop.
Perhaps not, seeing as they may (possibly) have plenty of the stuff in
all the hydrogen cooled generating sets in their power stations, maybe
they might consider giving one a special service connection, for a
price of course!!
> However, some audiophiles are fortunate to have sound electrical
> wiring in their homes, and satisfactory electrical service.
Where have you been living?!?!? Outside of some countries
euphemistically referred to as the 'Third World" my experience is that
the wiring in domestic dwellings, commercial and industrial premises
is usually sound, in accordance with the regulations of the relevant
electrical utility/authority, particularly in locations where people
can 'afford' to own high end electrical equipment, not just audio! If
unsound wiring installations are to be found, it is usually in
agricultural/farm locations where, it used to be said when I was a
young engineer, farmers are quite likely to try and use a wet string
to carry the current to their appliances. Overstating the case?
Perhaps, but in the past I have found such things as hammer mills, arc
welders on farms powered by such things as bell wire, twisted lighting
flex, and light guage electrical wiring inside metal conduits where
the insulation had melted and the copper had fused to itself and the
conduits! (though not yet in Australia)
> In such cases, do you find it difficult to accept that a bad
> electrical cord could be a "weak link"?
Seeing as you mention it what, exactly, constitutes a 'bad' electrical
cord such that it might be a "weak link", apart from not being made to
UL/CSA, IEC or other standards depending on the country in which one
lives.
Thanking you in anticipation
regards
Patrick Scully
Fremantle, Western Australia
Scott Frankland
James W. Durkin wrote:
> What's lurking in the $200 certified audiophile cable that is going
> to substantively better that?
Well, if it's anything more than a FILTER I don't think it'll do any
good! It's also not a bad idea to keep all connector sockets CLEAN in
order to minimize spurious noise. I like Cramolin Red preservative for
this. Before applying I recommend the use of a welder's "toothbrush".
These are brass or stainless bristle brushes about the size of a large
toothbrush. Works good for tube pins, too! :-)
~SF~
EC...@impulse.net
One simple question that I believe should be asked...
Have you actually TRIED some of the better power cords in your system?
I am surprised that the moderator allowed you to ask this sort of
question without a qualifying statement such as "I tried such and
such's and so and so's power cable and didn't hear any difference at
all".
[ I think the poster would be well served to both reread the original
post in this thread and the newsgroup's guidelines. There is
nothing in either that would suggest it's at all inappropriate to
ask a substantive question about a particular product or product
genre without having first heard that product or products in that
category. What was asked was an abstract question, and a reasonable
good one at that (as such beasts go). One needn't have tried it
first before pointing out the inherent risk in tweaking a tiger
about the nose. -- jwd ]
Experience has taught me that some equipment benefits greatly from
changing power cords, some does not. I believe it is mostly in the
reduction of radiated noise and your particular equipments design and
vulnerability to this radiated noise that determine whether or not you
hear any differences (after all, your power cord puts off quite a nice
magnetic field, and it is the ONLY part of the chain of power that
actually comes near to your gear). The better power cords seem to
minimize this noise which is one reason that there seem to be more
benefits from replacing power cords at the source and preamplification
ends...where this radiated noise can be further amplified up the line.
Note that similar benefits can often be had by moving a poorly
shielded preamplifier away from your power amplifier amp which also
radiates quite a bit of noise.
Just my opinion!
--
Kevin
E.C.S. New/pre-owned audio/home theater equipment.
Santa Barbara California. 805-685-6544.Fax 805-961-4993
We accept Visa/Mastercard/American Express/Discover.
www.ecsaudio.com
jj, curmudgeon and all-around grouch
In article <5ajf7j$m...@tolstoy.lerc.nasa.gov> Curtis Leeds
<cle...@mail.idt.net> writes:
> of course, your utility will laugh at you if you request OFC copper
> wire at your service drop.
You'll find that most laugh if you act like you expect any kind of
copper wire in your service drop.
One of my peeves is that utilities around here commonly use drop
cables that are simply too small to maintain good loss levels under
surge conditions. This is certainly irritating when a surge causes
the CD player to outright glitch (by surge here I mean demand surge
that causes low voltage for a second or 3).
One of the nice things about my new house is that I don't have a well
pump that provides me with lots of these motor-starting surges. :-)
--
Copyright alice!jj 1997, all rights reserved, except transmission by USENET
and like facilities granted. This notice must be included. Any use by a
provider charging in any way for the IP represented in and by this article
and any inclusion in print or other media are specifically prohibited.
Curtis Leeds
Fremantle Cockburn Enterprise Agency Inc wrote:
> For the purposes of general enlightenment, please define the variables that
> constitute 'quality' in an electrical power supply cord, such that "real
> improvements" might be made to the performance of one's audio/video system
> other than, e.g., current carrying capability, voltage drop per unit length,
> insulation, and possibly the contact and corrosion capabilities of the
> plug/socket pins/receptacles!! I was unaware that there were any other
> relevant factors besides UL/CSA, VDO, IEC, or other standard specifications,
> but having an open mind I'm willing to hear about new ones!!
This demand for such an explanation is rather odd, since I never made
any claims for high-end power cords. Why are you asking me these
questions?
> >And, of course, your utility will laugh at you if you request OFC copper
> >wire at your service drop.
> Perhaps not, seeing as they may (possibly) have plenty of the stuff in all the
> hydrogen cooled generating sets in their power stations, maybe they might
> consider giving one a special service connection, for a price of course!!
Here, you are quite mistaken; they will most positively laugh. Indeed,
copper is no longer used in most areas for electrical distribution.
Aluminum is the almost universal choice. (It's cheaper.)
> Where have you been living?!?!? Outside of some countries euphemistically
> referred to as the 'Third World" my experience is that the wiring in domestic
> dwellings, commercial and industrial premises is usually sound, in accordance
> with the regulations of the relevant electrical utility/authority,
> particularly in locations where people can 'afford' to own high end electrical
> equipment, not just audio! If unsound wiring installations are to be found,
> one likely source I have found is in agricultural/farm locations...
Well, I live in the Northeastern United States, and I can say that you
are in error to believe that your experience is in any way
representative. There are two issues here, really: first, the quality
of electrical service and second, the quality of the house-wiring. As
to the electrical service itself, AC quality (satisfactory voltage,
current, and power ratio) is not guaranteed and, indeed, can be
marginal at best. The utility companies have been over-taken by
merger-mania, and do not necessarily maintain lines and systems the
way they should and once did. In my particular case, I engaged in a
multi-year battle with my utility for years. (This involved lawyers,
engineers, the state Board Of Public Utilities, how much detail would
you like?) I wasn't willing to accept service that varied from 91 VAC
to 155VAC, and I wasn't willing to accept the utility's inability to
deliver satisfactory current, either. I can tell you from first-hand
knowledge that utilities are not interested in audio matters, and they
are often not interested in basic electrical service delivery, either.
Especially at the residential level. Only a fool would assume that
service is always within specification.
The second issue is of the house wiring itself. While the NEC
should assure sound practices, it is often ignored. Volume builders
cut corners frequently (a series of law suits is now under way in the
town adjacent to me over just this) and codes are ignored.
Furthermore, some owners undertake repairs and improvements without
building permits; many do their own work and will not construct within
code. So it's a mistake to assume that any home's wires are within
code unless they've been checked, or unless the history of the house
is very well known.
Again, I made no claims whatsoever for high-end power cords; I
only observed that electrical service is often marginal. If you doubt
my claims, my battle with my electrical utility is a matter of the
public record at the New Jersey Bioard Of Utilities, Electrical
Division. You could, as they say, "look it up". Based on your
comments, you'd be surprised.
James Durkin
Scott Frankland <audi...@ix.netcom.com> writes:
> James W. Durkin wrote:
>> What's lurking in the $200 certified audiophile cable that is going
>> to substantively better that?
> Well, if it's anything more than a FILTER I don't think it'll do any
> good!
Good point, but one that begs a question. Why bother?
It would make a whole lot more sense in my book if you just opted for
a power conditioner (read "filter") to rid the line of any demons
(pick your favorite) left at the outlet. That way you "filter" for
the whole lot, and not just one component. If you're worried about
current limiting on amps, then leave some unfiltered outlets on the
power conditioner or just plug the amps directly into the wall.
All that said, I'm trying to think of what companies offer power cords
with some type of "obvious" (potential?) filter element. MIT,
Transparent, Tice. Any others? Now for the million dollar question.
Anyone have an idea as to what's lurking in these boxes? Maybe a
wristwatch in the case of the Tice (just a thought)?
P.S.:
When I mentioned the $200 "certified audiophile" power cord, I was
essentially parroting (as far as price goes) the original poster.
While browsing the January '97 S'phile, I came across the following:
World's Greatest AC Power Cord?
Hear what the critics have to say...
Essential Sound Products, Inc.
The Essence Power Cord:
- Multi-conductor, patent pending geometry.
- Proprietary connector components & termination process.
- Shielding prevent RFI & EMI emmisions for the quietest
backgrounds.
- Precise soundstaging & resolution.
$499 / 6 ft. (January Special Only $449)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
||||||||||||||||||||||||||||||||||||||||
[ shamelessly ripped form an ad for dynaTEK Audio/Video & Home
Cinema, pp. 278-279 ]
--
James Durkin
j...@graphics.cornell.edu
"High-end audio. Unsafe at any price?"
Charlie Hand
In article <5ar62q$g...@eyrie.graphics.cornell.edu>,
>> However, some audiophiles are fortunate to have sound electrical
>> wiring in their homes, and satisfactory electrical service.
>Where have you been living?!?!? Outside of some countries
>euphemistically referred to as the 'Third World" my experience is that
>the wiring in domestic dwellings, commercial and industrial premises
>is usually sound, in accordance with the regulations of the relevant
>electrical utility/authority, particularly in locations where people
>can 'afford' to own high end electrical equipment, not just audio! If
Here in the USA we have a little thing called "political corruption".
In my neighborhood, built in 1970, all the receptical boxes in the
neighbornood are gradually, one-by-one, blowing up (except for the
ones which are re-wired before they blow up). The cause? Crimp
connections - very dangerous - fully conformant to regulations - fully
government-inspected - very cheap to the builder.
I think they only just recently outlawed aluminum wire, but only in
certain applications.
Richard D Pierce
In article <5aroso$p...@agate.berkeley.edu>,
Curtis Leeds <cle...@mail.idt.net> wrote:
[ cut -- rgd ]
>Here, you are quite mistaken; they will most positively laugh. Indeed,
>copper is no longer used in most areas for electrical distribution.
>Aluminum is the almost universal choice. (It's cheaper.)
Small correction. That aluminum is cheaper than copper is certain, though
it's not THAT much cheaper, material-wise. The primary reason to use
aluminum is its superior combination of mechanical vs electrical
properties, which it has an advantage over copper.
Copper has a conductivity of 1.67 uOhm cm and a density of 9 g/cm^3.
Aluminum has a conductivity of 2.65 uOhm cm and a density of 2.7
g/cm^3. Thus, for a given electrical resistance, aluminum is less
than half the weight of copper (but requires about 60% greater
cross-sectional area, or cables about 25% greater diameter). That
means less supported weight on overhead transmission, lower costs in
stringing and maintaining cables, and so forth.
And the power company is VERY interested in lowest possible resistance
in transmission wires because the higher the resistance, the greater
the ohmic losses (electrical power transformed directly to heat), and
since that loss is not metered, it's an economic loss for the power
company.
It makes good economic sense for the power companies to use aluminum
transmission lines, and it makes good economic sense to make sure that
there's enough aluminum there to minimize power losses.
As long as the net electrical resistance is the same, it makes little
difference.
Now there's a secondary effect in that terminating and connecting
aluminum poses that may be an issue. However, copper poses it's own
set of problems as well.
--
| Dick Pierce |
| Loudspeaker and Software Consulting |
| 336 Broadway Hanover, MA 02339 |
| (617) 826-4953 (Voice and FAX) |
brad sanders
In <5ar9c8$h...@eyrie.graphics.cornell.edu> EC...@impulse.net sez:
>One simple question that I believe should be asked...
>
>Have you actually TRIED some of the better power cords in your system?
>Experience has taught me that some equipment benefits greatly from
>changing power cords, some does not. I believe it is mostly in the
>reduction of radiated noise and your particular equipments design...
Absolutely true. Although they are al plugged into the SAME outlet
strip (yep, I admit it: purchased for ten bucks at the local building
supply) the power cord from my CD player (when the CD player is ON)
needs to stay VERY far away, and misaligned to, my TV and VCR power
cords, lest I be watching the world through waves of heterodynes. Note
the equipment does not move, and they ALL SHARE THE SAME OUTLET.
Now, I'll ask you: Have YOU ever tried comparing those RIDICULOUSLY
over priced "power cords" with a very good flexible conduit? One can
buy very soft, pliant, three conductor cable with an equally soft,
pliant, outer shield - for FAR LESS than the $133/foot or so charged
by many of these absurdists.
> http://radioactive.home.ml.org <-------------------------------
Steve Nugent
Gary S. Bekkum wrote:
> James W. Durkin wrote:
> [snip -- moderator bt]
> > What's lurking in the $200 certified
> > audiophile cable that is going to substantively better that?
> Do any of the high-end power cords use special shielding that would
> reduce RF/EMI pickup or transmission? Consider that the power cords
> in your equipment are closest to your audio system, and any leakage or
> pickup of noise would be concentrated there. The house wiring would
> run away from your home run area (although it might pick up noise from
> other appliances and computers etc.) Any one else have thoughts on
> this?
My experience with shielded cords is that they add significant
capacitance and reduce the transient response of power amplifiers and
preamps. They can improve the performance of DAC's however. The best
cord that I have found is simply three 12 gauge solid wires twisted
together with no shield. This cord improved the transient response of
my DAC and power amplifiers. The same cord built with stranded is
inferior to the solid. If you don't mind the fact that it is stiff, I
would highly recommend solid copper.
Steve N.
Curtis Leeds
Steve Nugent wrote:
> My experience with shielded cords is that they add significant
> capacitance and reduce the transient response of power amplifiers and
> preamps.... If you don't mind the fact that it is stiff, I
> would highly recommend solid copper.
This poster should also have mentioned "...if you don't mind creating
a fire hazard..." as part of his disclaimer. Solid conductor cable is
not recommended for use as a power cord; it is not designed to be
flexible. The conductor will gradually weaken as it is moved about
(for vaccuuming, dusting, etc.), increasing its resistance. You can
figure out for yourself the potential result.
As always, one should be cautious whenever modifying electrical
devices, and skeptical about taking advice from people not qualified
to issue it.
Andy Moss
EC...@impulse.net wrote:
> Experience has taught me that some equipment benefits greatly from
> changing power cords, some does not. I believe it is mostly in the
> reduction of radiated noise and your particular equipments design and
> vulnerability to this radiated noise that determine whether or not you
> hear any differences (after all, your power cord puts off quite a nice
> magnetic field, and it is the ONLY part of the chain of power that
> actually comes near to your gear). The better power cords seem to
> minimize this noise which is one reason that there seem to be more
> benefits from replacing power cords at the source and preamplification
> ends...where this radiated noise can be further amplified up the line.
> Note that similar benefits can often be had by moving a poorly
> shielded preamplifier away from your power amplifier amp which also
> radiates quite a bit of noise.
This is nonsense. I think it can be extrapolated that a *better*
power cord is capable of carrying more electric current. Therefore
it's resistance is, obviously, lower. When this is the case, the
amount of current that can be carried through this cord is increased
(for the given voltage). When the current is increased (if at all!)
the magnetic field is also increased. The increased field, by your
reckoning, can be induced into the audio cables of your system. So
consequently, a better cable will sound worse, no?
> Just my opinion!
Just grade ten physics!
Cheers!
--
Andy Moss
"I often fantasize about my inability to daydream....."
hen...@nortel.ca
Steve Nugent (Steve_F...@ccm.jf.intel.com) wrote:
: My experience with shielded cords is that they add significant
: capacitance and reduce the transient response of power amplifiers and
: preamps.
If it wouldn't be too much trouble, could you post some figures on
the amount of capacitance added? It would also be interesting to see
a description in objective terms of the change in transient response
and perhaps some analysis of the mechanism by which this occurs.
Thanks in advance.
-Henry
--
ATTENTION! Reply to h...@nortel.ca (hen...@nortel.ca won't work).
jj, curmudgeon and all-around grouch
In article <5aroso$p...@agate.berkeley.edu> Curtis Leeds
<cle...@mail.idt.net> writes:
>I wasn't willing to accept service that varied from 91 VAC
>to 155VAC, and I wasn't willing to accept the utility's inability to
>deliver satisfactory current, either.
Just in case there's any doubt. I used to live about 30 miles ene of
Curtis. I didn't have that problem, but I used to have 138-140V
service all the time, until I read the riot act to the
"damnpowercompany". And that with about 1 outage/week, too.
Good service is NOT universal.
--
Copyright alice!jj 1997, all rights reserved, except transmission by USENET
and like facilities granted. This notice must be included. Any use by a
provider charging in any way for the IP represented in and by this article
and any inclusion in print or other media are specifically prohibited.
Bob Myers
Steve Nugent (Steve_F...@ccm.jf.intel.com) wrote:
> My experience with shielded cords is that they add significant
> capacitance and reduce the transient response of power amplifiers and
> preamps. They can improve the performance of DAC's however. The best
How would shielding a POWER CORD - which is presumably what we're
talking about here - "reduce the transient response of power
amplifiers"? Adding capacitance to the AC line is (within reason) a
good thing, as it could possibly cause a slight reduction in conducted
high-frequency noise. The first thing said power is going to see
after rectification in the power supply happens to be some ungodly
HUGE capacitors, anyway.
> cord that I have found is simply three 12 gauge solid wires twisted
> together with no shield. This cord improved the transient response of
> my DAC and power amplifiers. The same cord built with stranded is
> inferior to the solid. If you don't mind the fact that it is stiff, I
> would highly recommend solid copper.
Solid copper for a POWER CORD? Don't do it. It's OK for running
inside the walls where it won't be flexed, but an exposed
solid-condutor power cord is asking for trouble. What happens if the
safety ground is the first to break? For that matter, why would a
stranded-wire power cord be inferior to solid? (I'm a bit surprised
that one got through without SOME justification to back it up!)
[ Sometimes Bob, moderators better serve the readership if they let
misinformation through that will be clearly and unequivocally
corrected by people such as yourself. Ultimately, it's a more
'educational' process. Thanks Prof. Bob. :-) jwd ]
--
Bob Myers KC0EW Hewlett-Packard Co. |Opinions expressed here are not
O- Workstations Systems Div.|those of my employer or any other
my...@fc.hp.com Fort Collins, Colorado |sentient life-form on this planet.
Richard D Pierce
In article <5b2v3t$r...@eyrie.graphics.cornell.edu>,
jj, curmudgeon and all-around grouch <j...@research.att.com> wrote:
>In article <5aroso$p...@agate.berkeley.edu> Curtis Leeds
><cle...@mail.idt.net> writes:
>
>>I wasn't willing to accept service that varied from 91 VAC
>>to 155VAC, and I wasn't willing to accept the utility's inability to
>>deliver satisfactory current, either.
>
>Just in case there's any doubt. I used to live about 30 miles ene of
>Curtis. I didn't have that problem, but I used to have 138-140V
>service all the time, until I read the riot act to the
>"damnpowercompany". And that with about 1 outage/week, too.
On the other hand, I recently moved out of a rural community about 45
miles NW of Boston where for 13 years the poer coming in from the
street was absolutely rock-steady. 120 VAC and I never saw more than
about +-4 volts variations, with two exceptions. One was when the
rasied bed from a dump truck crushed the transformer out on the pole
(93 volts in one leg, 20 in the other, yikes!) and the other when, one
summer day, I was working and all of a sudden the lights in my office
dimmed for about 5 seconds, to be replaced by an equally long VERY
bright blue glow coming in through the window accompanied by a
crackling sound. Then there was, simultaneously, a momentary loss of
power and a CRACK! sound. I immediately called the local gendarmerie
to suggest there may have been an auto accident then rushed
outside. The good police arrived just as I got to the street, where we
both discovered, sitting under a pole, the smoking remains squirrel
pelt at the end of a trail of smoke that lead up to the insulators at
the top of the nearest telephone pole.
What remained of the face had a VERY distinctive look, that of a
rodent interuppted in the middle of saying "Oh, sh--".
Arnold B. Krueger
Gary S. Bekkum <gsb...@ix.netcom.com> wrote i
> Do any of the high-end power cords use special shielding that would
> reduce RF/EMI pickup or transmission? Consider that the power cords
> in your equipment are closest to your audio system, and any leakage or
> pickup of noise would be concentrated there. The house wiring would
> run away from your home run area (although it might pick up noise from
> other appliances and computers etc.) Any one else have thoughts on
> this?
The purpose of the power supply of a piece of audio equipment is to
take whatever comes in though the power line (within the design specs)
and turn it into beautifly pure stuff to run what's inside.
Any power source that meets the design specs for the power supply
should suffice. Procedures for designing equipment to reject
undesireable power line disturbances are well known.
Contrary to what may be popular belief, audio equipment does not have
the greatest potential to be upset by environmental noise, and does
not have the greatest tendency to contaminate the environment with
electrical noise and power distrubances.
Technology that works in those areas where these problems are REALLY
severe is highly developed, readily available, not egregiously
expensive, and applies readily and well to audio equipment.
Philip Ganderton
Hopefully more than just another comment to the effect that I heard a
difference, so it must be doing something:
I have recently been listening to AC power cords in a
non-scientific way, and have found them to make significant
differences in the sound of my system (Krell, B&W, Purist). The local
dealer talks about power correction factor, but I dont have enough
background to follow these arguments (poorly informed and constructed
as the ones that I have heard are). However, I do have a response to
those who argue that 1.5m of AC cord cant make any difference when
there is miles of crappy wire from the generating plant, and then
yards of crappy wire in my house to the outlet: if I have a simple
lenght of wire, and I place an active component (say a resistor) in
series with it, then the effect of the resistor is independent of
where I place it in the wire: at the beginning, at the end, or in the
middle. *If*, as I would argue, the power cord is an active
component, then so long as it is somewhere in the system (and where
better to localize its effect than directly before the audio
component) it is having its effect.
I think that some manufacturers (including a local tweeker in
town) are making their power cables into quite active components,
playing with capacitance and inductance (eg, is it possible to "tune"
a power cable?). And this is why some people hear differences.
(Ooops, now there's a statement...)
Well, anyway, all this fits in with my "new" appreciation of
how the entire system, all components, interact to produce a "sound":
and how changing one component can often create more of a change than
it would seem to warrant. Sort of like the fallacy of composition:
that the whole is something different from just the sum of its parts.
Whatever,
Cheers,
philip ganderton
Bob Myers
Philip Ganderton (gan...@unm.edu) wrote:
> middle. *If*, as I would argue, the power cord is an active
> component, then so long as it is somewhere in the system (and where
> better to localize its effect than directly before the audio
> component) it is having its effect.
Just as an FYI for the future: "active" components are generally meant
to be those which provide amplification or a similar function; another
way to look at it would be a component which consumes power NOT
directly related to its action on the signal or current it's
modifying. Examples are transistors & tubes. The other main category
of components are called "passive" components, and that's what an
engineer would call a resistor, capacitor, or inductor. This, of
course, has no bearing at all on this discussion, but I thought it
would be good to get us all speaking the same language.
> I think that some manufacturers (including a local tweeker in
> town) are making their power cables into quite active components,
> playing with capacitance and inductance (eg, is it possible to "tune"
> a power cable?). And this is why some people hear differences.
> (Ooops, now there's a statement...)
The problem with this line of reasoning is that the power cords aren't
in the signal path; certainly their characteristics might have an
effect on the 60 Hz (50 Hz in a goodly part of the planet, of course)
AC power, but that is far removed from the audio signal itself. In
fact, there is a rather large modifier-of-line-current between the
cord and those stages which directly handle the audio signal: the
power supply, which is supposed to be making one or more *DC* supplies
out of the AC line current. Now, it IS possible that noise on the AC
line might make it through to the DC used in the amp, and therefore
into the output, but those of us who prefer not to consider exotic
power cords will say that (a) this is indicative of a less-than-robust
power supply design, and (b) the power cord is a poor place to be
making fixes to compensate for that. The cord COULD do some
filtering, etc., to clean up the line - but if this is a problem, you
can do a much better job with a real filter at the supply input. In
short, while it's conceivable that the cord might make a difference,
it would have to be pretty small, and a much better correction of the
problem could be had elsewhere with more ease.
Michael Hanz
Philip Ganderton wrote:
> ... if I have a simple
> length of wire, and I place an active component (say a resistor) in
> series with it, then the effect of the resistor is independent of
> where I place it in the wire: at the beginning, at the end, or in the
Philip is right in the basic concept. But consider what would be the
case if the active component has the same electrical properties as the
rest of the system, only less of it...(inductance, capacitance,
resistance)? Its contribution to effects is proportional to its share
of those properties from generating plant to appliance. Without
external inductors or capacitors added to the 6 feet of cable, its
share (and contribution) to tangible effects is pretty small compared
to the contribution of those properties by the house and distribution
wiring. You can see that clearly in the measurements presented in
earlier posts.
Just another way of looking at it...
--
Michael Hanz, P.E.
UNM EE '65
Herndon, VA
AAFR...@erols.com
Richard D Pierce
I'd like to gurther emphasis some of Bob's points:
In article <5bi3fd$s...@agate.berkeley.edu>,
Bob Myers <my...@hpfcla.fc.hp.com> wrote:
>Philip Ganderton (gan...@unm.edu) wrote:
>> middle. *If*, as I would argue, the power cord is an active
>> component, then so long as it is somewhere in the system (and where
>> better to localize its effect than directly before the audio
>> component) it is having its effect.
>
>Just as an FYI for the future: "active" components are generally meant
>to be those which provide amplification or a similar function; another
>way to look at it would be a component which consumes power NOT
>directly related to its action on the signal or current it's
>modifying.
This is a particular source of difficulty in communicating between
people. "Active component" is a very specific term that has been in
use LONG before high end audio. It has a meaning that is well
understood and unambiguous. Now, we see the term "active component"
applied to something which the entire engineering community agrees is
not an active component, thus confusing the discussion by a
misapplication of terminology.
The power cord is NOT an "active component" by convention and by
definition, despite the misapplication of the term by some advertisers
(I am not blaming Mr. Ganderton for this misuse, as I have seen it
agregiously applied by manufacturers who are supposed to know better
and some of whom have knowingly misused terminology to further their
own economic agenda).
Whether the power cord, being a PASSIVE component, is an IMPORTANT
component is another question altogther. But if it WERE and IMPORTANT
compoent does not make it and ACTIVE component.
>> I think that some manufacturers (including a local tweeker in
>> town) are making their power cables into quite active components,
>> playing with capacitance and inductance (eg, is it possible to "tune"
>> a power cable?). And this is why some people hear differences.
>> (Ooops, now there's a statement...)
>
>out of the AC line current. Now, it IS possible that noise on the AC
>line might make it through to the DC used in the amp, and therefore
>into the output, but those of us who prefer not to consider exotic
>power cords will say that (a) this is indicative of a less-than-robust
>power supply design, and (b) the power cord is a poor place to be
>making fixes to compensate for that.
I think this is the point that needs special emphasis:
If a power cord DOES make an audible difference, it's a strong
indicator not (as Bob politely suggested) of less-than robust
power supply designm, but of demonstrably BAD power supply
design.
One of the primary jobs of the power supply IS to isolate the active,
signal carrying electronics from the AC line. It can do that job FAR
better than a power cord can. The available range of design options in
doing the job in the power supply are FAR more vast than in the most
imaginative of power cables configurations. If the power supply is so
bad that a power cable changes its performance enough to be heard,
it's a sign of a bad power supply, NOT a sign of a great power
cable. Trying to fix a power supply with a power cable is like trying
to treat mutliple gunshot wounds with chewable aspirin, yeah, it might
relieve some of the symptoms, but it DOES NOT fix the problem.
jjz...@aol.com
In article <5bj34r$j...@canyon.sr.hp.com>, DPi...@world.std.com (Richard D
Pierce) writes:
>I think this is the point that needs special emphasis:
>
> If a power cord DOES make an audible difference, it's a strong
> indicator not (as Bob politely suggested) of less-than robust
> power supply designm, but of demonstrably BAD power supply
> design.
>
>One of the primary jobs of the power supply IS to isolate the active,
>signal carrying electronics from the AC line. It can do that job FAR
>better than a power cord can. The available range of design options in
>doing the job in the power supply are FAR more vast than in the most
>imaginative of power cables configurations. If the power supply is so
>bad that a power cable changes its performance enough to be heard,
>it's a sign of a bad power supply, NOT a sign of a great power
>cable. Trying to fix a power supply with a power cable is like trying
>to treat mutliple gunshot wounds with chewable aspirin, yeah, it might
>relieve some of the symptoms, but it DOES NOT fix the problem.
If properly designed power supplies are such that a change in the
power cord cannot improve its function, does the same conclusion hold
for power line conditioners which presumably do a much better job at
providing a clean, pure 60 Hz, 120 V signal to the power supply than
any power cord can? In other words are properly designed power
supplies robust enough to output clean, stable power to the circuits
in the face of the normal noises and voltage variations found on the
input to the power supplies? If so, and my belief is that it must be
so, how does one know whether a particular component has a properly
designed power supply without resorting to having to listen for
audible differences when the component is or is not plugged into a
power line conditioner?
Josh Ziff
bl...@vnet.ibm.com
My theory of why power cord improvements work is that they improve, or
at least change, the amount of electromagnetic interference entering
the equipment. I've looked inside my equipment, and none of it has any
EMI suppression stuff built in. This is 4-figure price tag gear, so
you would think they could afford it, but no. The power cord gets
pretty close to the interconnects and speaker cables where it can
couple EMI either to or from them (which isn't much of a problem with
wall wiring because it's so far away). The amp is broadbanded, so any
out-of-band junk from the CD player gets amplified, and could couple
back into the power cord. And/or, junk already on the power wiring
could couple to the interconnects and get into the amplifier input. It
seems reasonable to me that use of a shielded power cord on such
equipment could improve the situation.
From what I understand many of these expensive power cords are
shielded, though I didn't use one. What I did was cut the plug off,
slip two layers of shield braid over the cable, put on a better plug,
and put 3 big ferrite beads at the amplifier end (where the last few
inches are unshielded, because the beads didn't seem to do much when
put over the shielding). This does seem to improve things, although I
certainly can't "prove" it.
Bob
Steve Nugent
bl...@VNET.IBM.COM wrote:
> My theory of why power cord improvements work is that they improve, or
> at least change, the amount of electromagnetic interference entering
> the equipment.-snip
It
> seems reasonable to me that use of a shielded power cord on such
> equipment could improve the situation.
I have found just the opposite to be true. In every case when I have
tried to use clip-on ferrite cores to reduce EMI from going in or
coming out of amps, pre-amps and DAC's, the filter has compromised the
sound. I believe this is primarily due to poor power supply design.
The filter capacitance in the equipment is not low ESR, or the mix of
high and low capacitance values (decoupling) is not optimum and allows
droop to occur in the power on the circuit boards. My preference is
to attach my gear directly to the transformer on the pole. It is
difficult for me to believe that RF frequencies can get through the
toroidal power transformers and past the filter capacitors in typical
power supplies, not to mention regulators.
I measured the differences between shielded versus unshielded stranded
power cords when a complete system was driven by an impulse and a
square wave with slew rate of ~ .05V/Usec. I could measure no
difference, but the slew rate was rather low. I plan on trying again
with higher slew rate oscillator. I also plan to make measurements of
the power cables themselves. I suspect that the effect that I hear
when I have heard differences between shielded and unshielded power
cables is a a result of both high energy and transient waveforms. In
any case, I have found that the audible effect is subtle at best and
requires critical listening to detect. I have done various tweaks to
audio gear to improve the power supply filter capacitance and
decoupling, including a Velodyne subwoofer, which benefited greatly.
I have found that expensive equipment does not necessarily mean
quality power supplies and power distribution. Mark Levinson gear
does not appear to benefit much from power cord tweaks. This is a
good sign, if you have the money, and tends to support the claim that
the real effect with different power cords is to compensate for
deficiencies in power supplies.
Steve N.
Bob Olhsson
> If a power cord DOES make an audible difference, it's a strong
> indicator not (as Bob politely suggested) of less-than robust
> power supply designm, but of demonstrably BAD power supply
> design.
>
>... Trying to fix a power supply with a power cable is like trying
>to treat mutliple gunshot wounds with chewable aspirin, yeah, it might
>relieve some of the symptoms, but it DOES NOT fix the problem.
I hasten to point out that $100 for a tweak power cord is a LOT
cheaper than the difference in price between medium and top-quality
power supplies.
Certainly I agree that a great power-supply is the "right" approach
but practically-speaking it often isn't an option.
There ARE basics though, I just took some of my own advice and cleaned
my connections which has just made a DRAMATIC improvement. I've also
heard tightening up the (often 50+ year old) mains service connection
make a dramatic improvement that AC conditioning was a band-aid for.
--
Bob Olhsson Audio | O tongue, thou art a treasure without end.
Box 555,Novato CA 94948 | And, O tongue, thou art also a disease
415.457.2620 | without remedy. == Jelal'uddin Rumi ==
415.456.1496 FAX |
Bob Myers
Bob Olhsson (o...@hyperback.com) wrote:
> I hasten to point out that $100 for a tweak power cord is a LOT
> cheaper than the difference in price between medium and top-quality
> power supplies.
True, but then there's so very little that this $100 "tweak power
cord" can do that wouldn't be done FAR better by spending the same
amount on an add-on filter. Unless, of course, the power cord has
included with it a filter (meaning that there's a box of discrete
components tacked on to the cord) - this gives you the same results
but in a whole lot sillier package!
Chuck A Haser
[ quoted text deleted -- jwd ]
A couple of years ago someone mentioned to me to replace my power
cords with Kimber Cable TC4. I never did it. Any thoughts on it?
Richard D Pierce
In article <5bm44p$4...@eyrie.graphics.cornell.edu>, <jjz...@aol.com> wrote:
>In article <5bj34r$j...@canyon.sr.hp.com>, DPi...@world.std.com (Richard D
>>I think this is the point that needs special emphasis:
>>
>> indicator not (as Bob politely suggested) of less-than robust
>> power supply designm, but of demonstrably BAD power supply
>> design.
>>
>>signal carrying electronics from the AC line. It can do that job FAR
>>better than a power cord can.
>>it's a sign of a bad power supply, NOT a sign of a great power
>>to treat mutliple gunshot wounds with chewable aspirin, yeah, it might
>>relieve some of the symptoms, but it DOES NOT fix the problem.
>
>power cord cannot improve its function, does the same conclusion hold
>for power line conditioners which presumably do a much better job at
>providing a clean, pure 60 Hz, 120 V signal to the power supply than
>any power cord can? In other words are properly designed power
>supplies robust enough to output clean, stable power to the circuits
>in the face of the normal noises and voltage variations found on the
>input to the power supplies? If so, and my belief is that it must be
>so, how does one know whether a particular component has a properly
>designed power supply without resorting to having to listen for
>audible differences when the component is or is not plugged into a
>power line conditioner?
Let's play devils advocate for the moment and presume that a line
conditioner DOES make a real improvement in the action of the power
supply, and let's compare that to that of a line cord.
Power conditioning units have a number of devices that enable them to do
their job:
1. Varistors, transorbers or other such non-linear devices that
prevent excessive voltage spikes from being passed into the
power supply.
A power cord, no matter how expensive or sophisticated, has NO such
capability of ANY kind.
2. Common mode inductors to reduce common mode noise on the line.
A power cord has a very small effective, several orders of magnitude
less, common mode inductance compared to those found in a power
conditioning strip.
3. Parallel high frequency bypass capacitors to shunt high frequency
noise and interference (such as RF interference, switching transients,
and the like).
A power cord has several orders of magnitude lower capacitance, and
thus is, by its very nature, several order of magnitude less effective
at shunting high-frequency noise and interference.
5. A power conditioner may have current limiting of some sort (even as
simle minded as a circuit breaker) to protect the load from destroying
itself or causing excessive current draw from the unit.
I once saw a power cord get so hot it melted the insulation and
started a fire. Does that count? :-)
4. It's possible that a power conditioner may also have series inductors
that, combined with the above mentioned capacitors, results in a
steeper rolloff slope, lower cutoff frequency and better attenuation
of high frequency interference.
A power cord has a very low effective inductance which, combined
with its low parallel capacitance, results in a far less effective
HF filter because of its much higher cutoff frequency (tens of MHz).
No, there is absolutely NO reason why all of these measures cannot be
incorporated as part of the power supply design in the first
place. The surprising thing is that ALL the parts in these sorts of
power conditioners are pretty damned cheap and readily available, a
fact that belies both their retail price (in some cases) and their
relative rarity in power supply.
However, if you are going to make the comparison between a power cord
and a power conditioner, then do it fairly using consistant
criteria. What a power conditioner does beneficially (that which it is
designed to do), a power cord does 1/1000 of and, in many cases, not
at all.
And, once again, if the power supply is properly designed to begin
with, adding a power conditioner is somewhat redundant and may not
make a hill of beans difference.
Ian J. Smith
Steve Nugent wrote:
>
> My preference is
> to attach my gear directly to the transformer on the pole. It is
> difficult for me to believe that RF frequencies can get through the
> toroidal power transformers and past the filter capacitors in typical
> power supplies, not to mention regulators.
>
My experience has led me to show eactly the opposite is true! RF
frequencies are readily picked up by and/or conducted on power lines
around the home. A typical toroidal transformer has so much
inter-winding capacitance, that any RF goes straight across to the
secondary. The electrolytic filter capacitors have too much inductance
to attenuate RF, so it's all up to the little ceramic capacitors next
to the regulators. By then the RF has radiated all around the
equipment because of all the internal wiring. The regulator also only
regulates up to a few kHz and just passes the RF.
IMHO the only way to stop interference is a proper common-mode RF
filter on the mains input to the equipment. Ideally the box will be
all metal and all lines in and out will be filtered.
Here in Europe we have regulations that cover not just RF emissions,
but also susceptibility to in-coming interference, so RFI is
considered as a whole. Sadly, as far as I know, it does not cover
hi-fi!!!
--
Ian J. Smith BEng CEng MIEE i...@lucent.com
Senior Wireless Engineer
Lucent Technologies Network Systems UK (formerly AT&T)
Disclaimer: the views expressed above are mine and not
necessarily those of my employer.
Stewart Pinkerton
"Ian J. Smith" <no_retur...@lucent.com> writes:
>Here in Europe we have regulations that cover not just RF emissions,
>but also susceptibility to in-coming interference, so RFI is
>considered as a whole. Sadly, as far as I know, it does not cover
>hi-fi!!!
The regulations most certainly DO cover hi-fi and all CE-marked
equipment meets both emissions and susceptibility requirements. This
has led to noticeable differences in the sound of many components,
generally for the better now the designers have got a hold of the
technology. Check the latest Audiolab and Meridian gear to hear this
done well, typically giving additional smoothness to the sound and
reducing sensitivity to power line interference.
--
Stewart Pinkerton | If you can't measure what you're making,
A S P Consulting | how do you know when you've got it made?
(44) 1509 880112 |
"I canna change the laws o' physics" - the other Scotty
jjz...@aol.com
> In other words are properly designed power
>supplies robust enough to output clean, stable power to the circuits
>in the face of the normal noises and voltage variations found on the
>input to the power supplies? If so, and my belief is that it must be
>so, how does one know whether a particular component has a properly
>designed power supply without resorting to having to listen for
>audible differences when the component is or is not plugged into a
>power line conditioner?
In article <5c0udd$t...@canyon.sr.hp.com>, DPi...@world.std.com (Richard D
Pierce) answers:
>And, once again, if the power supply is properly designed to begin
>with, adding a power conditioner is somewhat redundant and may not
>make a hill of beans difference.
>
Thanks for your answer, Dick, and for explaining the factors that go
into the design of a good power supply or line conditioner. But, the
question was: how is a consumer to know, without resorting to a
listening test, if an audio component has a good enough power supply
such that the need and expense of a line conditioner is unnecessary?
Josh Ziff
Kazushi Endoh
my...@hpfcla.fc.hp.com (Bob Myers)wrote:
>Bob Olhsson (o...@hyperback.com) wrote:
>> I hasten to point out that $100 for a tweak power cord is a LOT
>> cheaper than the difference in price between medium and top-quality
>> power supplies.
Top-quality to super-top-quality upgrade needs double to triple costs,
in general.
>True, but then there's so very little that this $100 "tweak power
>cord" can do that wouldn't be done FAR better by spending the same
>amount on an add-on filter. Unless, of course, the power cord has
>included with it a filter (meaning that there's a box of discrete
>components tacked on to the cord) - this gives you the same results
>but in a whole lot sillier package!
I have never seen a good sounding AC filter. In addition, pure sine
wave generator or error correcting AC amp, they are extended concept
of AC filter, can not work as good as "great power cords". These
active power conditioners are priced $5000 to $8000. (2kVA version is
close to $20,000) It is not easy, not cheap at all. -- Kazushi Endoh
Med.Univ.Yamanashi ken...@res.yamanashi-med.ac.jp
Bob Myers
Kazushi Endoh (ken...@res.yamanashi-med.ac.jp) wrote:
> >True, but then there's so very little that this $100 "tweak power
> >cord" can do that wouldn't be done FAR better by spending the same
> >amount on an add-on filter. Unless, of course, the power cord has
> >included with it a filter (meaning that there's a box of discrete
> >components tacked on to the cord) - this gives you the same results
> >but in a whole lot sillier package!
> I have never seen a good sounding AC filter. In addition, pure sine
> wave generator or error correcting AC amp, they are extended concept
> of AC filter, can not work as good as "great power cords". These
> active power conditioners are priced $5000 to $8000. (2kVA version is
> close to $20,000) It is not easy, not cheap at all. -- Kazushi Endoh
> Med.Univ.Yamanashi ken...@res.yamanashi-med.ac.jp
Sorry, Kazushi, but you'll have to tell us more than that. Just what
is it that you think these "great power cords" can do that can't be
done better via a discrete line filter? For that matter, if you have
never seen a good sounding AC filter, what do you do about the massive
filter that is going on in the front end of ANY power supply?
Kazushi Endoh
Steve Nugent <Steve_F...@ccm.jf.intel.com> wrote:
>I have found that expensive equipment does not necessarily mean
>quality power supplies and power distribution. Mark Levinson gear
>does not appear to benefit much from power cord tweaks. This is a
>good sign, if you have the money, and tends to support the claim that
>the real effect with different power cords is to compensate for
>deficiencies in power supplies.
Our local dealer uses Mark Levinson No 38L/332 for display, and 38L
shows great improvement by using my Purist's Proteus power cord. 38L
should not suffer from power deficiencies, it is not a heavy current
drawer. So the mechanism of improvement is different from power
deficiency. Since I have never seen a good sounding AC filter, the
mechanism of improvement is different from AC filtering too. I tried
Proteus power cord on several high priced systems, power amps were
$20,000 to $30,000 range. So far, I have never seen a system immune to
power cord (of course No332 was not immune).
In article <5bj34r$j...@canyon.sr.hp.com>, DPi...@world.std.com
(Richard D Pierce) writes:
[ cut -- rgd ]
>imaginative of power cables configurations. If the power supply is so
>bad that a power cable changes its performance enough to be heard,
>it's a sign of a bad power supply, NOT a sign of a great power
>cable.
Madrigal had better to agree "it's a great power cable", otherwise
their 38L has "The specially emphasised poor power supply", isn't it??
Does the Mark Levinson No 38L have so bad power supply? If so, do you
have any idea to improve No 38L? (Since my friends have No 38Ls.) No
38SL may also have poor power supply, I heard 38SL is just a Teflon
version.
The budget should be less than $500, since good power cord is
available at $450 (but they already have and using though...).
Kazushi Endoh
noca...@ix.netcom.com (Chuck A Haser) wrote:
>A couple of years ago someone mentioned to me to replace my power
>cords with Kimber Cable TC4. I never did it. Any thoughts on it?
You can hear almost same sound characteristics as used in a speaker
cable. I made several power cords from speaker cable, MonitorPC sounds
like MonitorPC, Tara sounds like Tara, etc. Kimber Kable is good for
power cord, since Teflon insulation is heat-resistant and physically
tough, sonically, unfortunately it was not my taste. Since MonitorPC
and VanDenHul have strong character, it is interesting to play
with. Try to feed CD transport:-). -- Kazushi Endoh
Med.Univ.Yamanashi ken...@res.yamanashi-med.ac.jp
Jeffery
DPi...@world.std.com (Richard D Pierce) wrote:
> However, if you are going to make the comparison between a power
> cord and a power conditioner, then do it fairly using consistant
> criteria. What a power conditioner does beneficially (that which it
> is designed to do), a power cord does 1/1000 of and, in many cases,
> not at all.
>
> And, once again, if the power supply is properly designed to begin
> with, adding a power conditioner is somewhat redundant and may not
> make a hill of beans difference.
About power conditioners, would you know if computer-grade power
conditioners. Like the American Power Conversion (APC) Smart-UPS be
good for hi-fi use?
Of course the UPS part might be unecessary, and although it says "for
computer loads only", I think it should be ok for not very power
quenching hifi use.
What I am wondering is that the Smart-UPS gives PURE SINE WAVE output.
I don't know how well it lives up to this capability, but it sure
sounds attractive. Theoretically, do you think this would be of any
use to hifi applications? Would it make any improvement in sound?
jeff.
Jeffery
Bob Myers
Kazushi Endoh (ken...@res.yamanashi-med.ac.jp) wrote:
> You can hear almost same sound characteristics as used in a speaker
> cable. I made several power cords from speaker cable, MonitorPC sounds
> like MonitorPC, Tara sounds like Tara, etc. Kimber Kable is good for
> power cord, since Teflon insulation is heat-resistant and physically
> tough, sonically, unfortunately it was not my taste. Since MonitorPC
> and VanDenHul have strong character, it is interesting to play
> with. Try to feed CD transport:-). -- Kazushi Endoh
Now, I find this very interesting, and it suggests to me that what's
going on here DOES have MUCH more to do with bias and expectations
than it does with any real objective effect on the sound.
After all, the power cord is most definitely NOT in the signal path,
and the supposed benefits of a "quality power cord" are MUCH different
than what effect we might expect speaker cabling to have on the signal
that it carries. The only reason that comes to mind as to why we
would expect "Tara to sound like Tara" is that the listener has a
preconceived notion as to what "Tara" products sound like. If someone
wants to object to this hypothesis, fine, but at least do me the
courtesy of telling me why this is an unreasonable assumption.
--
Peter Beyer
How does one explain the difference in sound by a powercord for a
class A Tube Amp? (e.g. current stays the same no mather how loud you
play)
I've heard it my self, I'am lost....
/Peter
Kazushi Endoh
"Power supply, how much good it should be?" in power cord resembles
"DIF, how much good it should be?" in digital interconnect. And
unexpectedly, I quoted Madrigal products in both cases. Maybe I'm
considering Madrigal as a good (standard) reference.
my...@hpfcla.fc.hp.com (Bob Myers) wrote:
> Sorry, Kazushi, but you'll have to tell us more than that. Just
> what is it that you think these "great power cords" can do that
> can't be done better via a discrete line filter? For that matter,
> if you have never seen a good sounding AC filter, what do you do
> about the massive filter that is going on in the front end of ANY
> power supply?
I don't know why/how power cord works, just I know fact that it works.
You can point out lots of cheap things are used in AC line, ordinary
hookup wires are used as internal wiring, nickel plated brass fuse
folder, cheap fuse, etc., but power cord works, that is fact.
I heard Goldmund and Spectral are doing something special in power
supply design. (In addition Goldmund is using good internal wire)
PS: I'm not believing Purist's voodoo like explanation of their cable.
James Durkin
ken...@res.yamanashi-med.ac.jp (Kazushi Endoh) writes:
> my...@hpfcla.fc.hp.com (Bob Myers) wrote:
>> Sorry, Kazushi, but you'll have to tell us more than that. Just
>> what is it that you think these "great power cords" can do that
>> can't be done better via a discrete line filter?
> I don't know why/how power cord works, just I know fact that it
> works. You can point out lots of cheap things are used in AC line,
> ordinary hookup wires are used as internal wiring, nickel plated
> brass fuse folder, cheap fuse, etc., but power cord works, that is
> fact.
One assumes by the statement "I know fact that it works" you mean that
expensive, aftermarket power cords offer an easily discernible sonic
improvement over the stock cords supplied with most high-end gear.
How do you *know* this to be so? As even a casual read of this group
will show, perception and reality are often something other than the
same thing. I'm sorry, but statements like "I know" smack of little
more than proof by assertion. Now please do share with us the
experiments/observations/whatever behind the knowledge.
--
James Durkin
j...@graphics.cornell.edu
SSS
In <5c0udd$t...@canyon.sr.hp.com> DPi...@world.std.com (Richard D
Pierce) writes:
>However, if you are going to make the comparison between a power cord
>and a power conditioner, then do it fairly using consistant
>criteria. What a power conditioner does beneficially (that which it is
>designed to do), a power cord does 1/1000 of and, in many cases, not
>at all.
>And, once again, if the power supply is properly designed to begin
>with, adding a power conditioner is somewhat redundant and may not
>make a hill of beans difference.
[ quoted text deleted -- jwd ]
I absolutely agree with what Dick has written. However, EVERY single
piece of audio equipment I've listened to from Krell, Mark Levinson,
Mcormack, Bryston, to the cheapest japanese, either Tubes or Solid
State, they ALL sounded slightly different with different power cords
and the differences were (and are) noticeable every single time the
power cords were (and are) changed.
They also sounded (and sound) different when plugged to line
conditioners like Panamax 1000 and Power Wedge. Sometimes the sound
quality improved (and improves) but sometimes it lost (and looses)
something.
Whether they have poorly designed power supplies, I don't know, but
Krell and Mark Levinson seem to be some of the most highly regarded
pieces of audio equipment.
The way I see it is like a very high performance sports car. It might
be the most perfectly designed car for the road, but unfortunately,
not all gas stations serve the same octane and clean gas. So, the car
will perform slightly different that what it's designers wished.
Sometimes adding an extra fuel filter solves the problem :)
This is my own experience and opinion.
--
Ramon E. De la Cruz
rdel...@iastate.edu
Kazushi Endoh
my...@hpfcla.fc.hp.com (Bob Myers) wrote:
> Now, I find this very interesting, and it suggests to me that what's
> going on here DOES have MUCH more to do with bias and expectations
> than it does with any real objective effect on the sound.
>
> After all, the power cord is most definitely NOT in the signal path,
> and the supposed benefits of a "quality power cord" are MUCH
> different than what effect we might expect speaker cabling to have
> on the signal that it carries. The only reason that comes to mind
> as to why we would expect "Tara to sound like Tara" is that the
> listener has a preconceived notion as to what "Tara" products sound
> like. If someone wants to object to this hypothesis, fine, but at
> least do me the courtesy of telling me why this is an unreasonable
> assumption.
You may need to consider fact that coloration in power cord is a
negative result for me, I just wasted such cord with coloration. I'm
expecting much better performance, because I would not like to pay
much for expensive power cords. In addition, I make cheap amps as a
hobby, I can't use $500 cord with $500 amp. I prefer XLO or Tara next
to silver solid core, since they have little coloration. (Silver solid
core is cheaper but availability of that I'm using is limited)
It is very interesting that power cord could add coloration on CD
transport. I expected VanDenHul work without coloration in the case of
CD transport, but it did coloration. Of course I know it is very
difficult to explain, it is NOT in the signal path, furthermore the
signal is digital!.
The worst cord I tested was DENON class 1 LC-OFC multi-stranded heavy
gauge cord (this was not cheap). Terrible, worse than cheap brass wire
for garden use. The best cord I tested may be Goldmund.
I'm going to buy another Goldmund power cord to examine effect-length
correlation, disassembling and changing macro characteristics, etc.
Bob Myers
SSS (rdel...@iastate.edu) wrote:
> The way I see it is like a very high performance sports car. It might
> be the most perfectly designed car for the road, but unfortunately,
> not all gas stations serve the same octane and clean gas. So, the car
> will perform slightly different that what it's designers wished.
> Sometimes adding an extra fuel filter solves the problem :)
This is going to go slightly astray from audio, but I think that this
brings up yet another excellent example of how people make buying
decisions based on their expectations, rather than on the basis of
real benefits.
For years, "high octane" gas has been marketed as "high performance"
gas - and it IS, to the extent that high-performance ENGINES often
require the higher octane levels. This has lead to the widespread and
completely erroneous belief that a given can will always perform
better with high-octane fuel; that the gas itself (or petrol, for
those of you like Stewart on the other side of the pond) improved
performance simply by being of a higher octane rating. And you can
find many, many people who will swear to this - that their cares just
perform better when filled with "super" rather than plain old regular.
In fact, no such performance boost occurs. The energy content of
gasoline is pretty much the same for all grades, independent of the
octane rating. But higher-compression (i.e., "high-performance")
engines require high octane fuel to prevent knocking - the octane is
acting to INHIBIT the combustion of the fuel. In short, the higher
octane gas permits higher performance - by permitting engines to be
designed with higher compression ratios - but is not itself the cause
of the performance improvement. As long as your particular engine
isn't knocking on regular, you're getting everything out of it you're
going to.
But this fact in no way prevents the public from buying high-octane
gas, often at a considerable premium (and make no mistake, the COST of
making this stuff isn't THAT much higher than regular; this stuff is
pushed because it's very profitable), even though there is absolutely
no real benefit over regular in the vast majority of cases (as can be
shown by anyone with a stopwatch). That some cars perform better than
others is easily shown, but the reason for this difference is being
completely misunderstood. Further, this same buying public will swear
that there IS a benefit to high-octane in their tanks, and will
continue to do so even after being shown conclusive evidence to the
contrary.
Now, why do so many people believe that audio somehow is immune to
this effect, or that the audio market works any differently?
Bob Myers | "Man will occasionally stumble over the truth, but
my...@fc.hp.com | most of the time he will pick himself up and continue."
O- | - Winston Churchill
James Wolf
On 20 Jan 1997 10:40:22 -0500, noca...@ix.netcom.com (Chuck
A Haser) wrote:
>A couple of years ago someone mentioned to me to replace my power
>cords with Kimber Cable TC4. I never did it. Any thoughts on it?
Yes, I made one with the kimber 8. On a McCormack DNA 0.5, I noticed
a more open and larger sound stage. Take care when putting it
together as it is stranded wire. I have not tried other aftermarket
power cords, so I can only comment on its performance vs. the OEM
cord.
I am also using the PowerWedge 114.
Good Luck
James Wolf
conn...@gol.com
In article <5chcbl$6...@agate.berkeley.edu>, my...@hpfcla.fc.hp.com
(Bob Myers) wrote:
> For years, "high octane" gas has been marketed as "high performance"
> gas. This has lead to the widespread and
> completely erroneous belief that a given can will always perform
> better with high-octane fuel; that the gas itself improved
> performance simply by being of a higher octane rating.
> In fact, no such performance boost occurs. As long as your particular engine
> isn't knocking on regular, you're getting everything out of it you're
> going to.
This is not altogether correct. The ECU (electronic control unit) of
many modern engines (particularly those in sports cars) will vary the
boost level (in the case of turbocharged engine), ignition timing,
valve timing etc. depending on the load encountered and the fuel
octane rating, in addition to the atmospheric density available. The
result is that changing the octance can have a measureable and
noticeable effect on the power and torque.
Once again, we see the danger of having preconceptions or false
expectations.
Hope this helps
--
jonathan c
Without comprehension, knowledge is nothing.
RAHE Moderator
This particular subthread has roamed rather far from being
audio-related. No further discussion related almost entirely to
automobiles, rather than audio, will be allowed. The subthread is
hereby terminated. The main thread itself is free to continue.
--
rgd, rd, jwd, bt
"the rec.audio.high-end moderating team"
Bob Myers
conn...@gol.com wrote:
> In article <5chcbl$6...@agate.berkeley.edu>, my...@hpfcla.fc.hp.com
> (Bob Myers) wrote:
>> For years, "high octane" gas has been marketed as "high
>> performance" gas. This has lead to the widespread and completely
>> erroneous belief that a given can will always perform better with
>> high-octane fuel; that the gas itself improved performance simply
>> by being of a higher octane rating.
>> In fact, no such performance boost occurs. As long as your
>> particular engine isn't knocking on regular, you're getting
>> everything out of it you're going to.
> This is not altogether correct. The ECU (electronic control unit) of
> many modern engines (particularly those in sports cars) will vary
> the boost level (in the case of turbocharged engine), ignition
> timing, valve timing etc. depending on the load encountered and the
> fuel octane rating, in addition to the atmospheric density
> available. The result is that changing the octance can have a
> measureable and noticeable effect on the power and torque.
Yes, but the basic point still holds - it is NOT that the
higher-octane gas is ITSELF responsible for the increase in
performance (i.e., there is no more power to be obtained from the gas
itself, just because it has a higher octane number). The higher
octance simply permits the ENGINE to work at the level it was designed
for. This is exactly backwards from the common misconception about
high-octane fuel, which is what I was trying to point out. Of even
greater significance, given the topics THIS group is worried about, is
that fact that the consumer will very often report an improvement from
using this gas when in fact no such gain actually exists.