"Powell" wrote in message
"Eeyore" wrote
If your budget is above $500 or so you might consider
a power line conditioning instead of perusing cables
as a source of increasing the overall resolution of your
system.
What do you mean by conditioning ?
Graham
There are four different classes of power conditioners:
1. General filtering
2. Specialized filtering: analog, digital, power amp
3. Specialized filtering with isolated transformers
4. Power regeneration
All completely necessary with good audio gear and normal wall socket power.
Sections:
I. What IS a Power Line Conditioner?
II. Why do I NEED/WANT one?
III. HTML Links
IV. Specific Products & Technology
V. Cheap Tweaks for the Dangerously Inclined
VI. Closing Comments
I. What IS a Power Line Conditioner?
=====================================
Before there was such a market for high end tweaks and
buzz words in high end audio/video companies like APCC & Tripplite
among many others were already making power conditioners for the
computer and electronics industry.
They are used only under exceptional conditions.
These devices are
still made and they are used to provide voltage
regulation for devices like copiers.
Go check the copiers in the building you work. Just about all of them will
be plugged into the wall without the intervention of a power conditioner.
They used
transformers with multiple taps, and as the input voltage
surges or sags the relays or transistors in the power
conditioner would switch among the different transformer taps.
Or, they used ferroresonant transformers.
I thought Tice or Audio
Power made a similar device, but I seem to be mistaken. Two good source of
non- esoteric power line conditioners are
www.furmasound.com and www.equitech.com. Pretty good
looking stuff if you have common surge/sagging problems.
For about $30 you can buy a line voltage monitor called a "Kill-a-watt". If
your power is sagging, it will tell you. All audio gear will function
nominally when the normal 120 volt power is in the range of 105 to 135
volts.
A line conditioner may have some features to do the
following:
1. Filter the AC signal so you get closer to
an ideal 60 Hz signal.
Generally unecessary. The power supplies in good audio gear can tolerate
very dirty AC power without audible problems.
2. Provide surge protection
Generally unecessary. The power supplies in good audio gear can tolerate a
wide range of surges.
3. Provide Under / Over voltage protection
(turns off)
Generally unecessary. The power supplies in good audio gear can tolerate a
wide range of voltage sources.
4. Provide Under / Over voltage regulation
(keeps the output voltage constant)
Generally unecessary. The power supplies in good audio gear can tolerate a
wide range of voltages. Audio gear that has internal circuits that are
critical of voltage levels have internal regulators.
5. Provide power outage protection
(like an Uninterruptable Power Supply)
Generally unecessary. In most places in the US, Canada, and Europe, the
power has very few outages. Power outages are more frustration than danger.
6. Provide a lower apparent impedance to the source
(like PS Audio, Elgar, etc.)
Generally unecessary for the reasons stated above. BTW, some of the tools
that are often unecesarily used by audiophiles to clean up power, end up
raising the source impedance of the power line. It's eaiser and more
sensible to disconnect them, than to use more expensive means to create any
difficulties that they may create.
Different products work differently, and will have
different feature mixes. The heavier, the more you are
paying for, so beleive it or not the cost per pound is a
good indicator of how much is going into the product,
Generally people don't have any problems with AC power. If its not broken,
don't fix it. If it is broken, then of course fix it. However the best means
for getting good AC power are pretty prosaic and don't involve high end
audio products. Get a professional electrician on the job, not some
saleshack on a web site or in an audio store.
Alas not all filtration is the same. Products which
claim to filter RFI/EMI only start to work at around 100
kHz or higher, which is far above human audibility. The
theoretically ideal power line filter would filter out
all signals below and above 60 Hz.
One of the best ways to filter HF noise out of AC power involves your
standard power transformer. They are intentially made with poor HF response.
They don't make good output transformers for tubed amps, but they do help
clean up the power. The next way involves the filter capacitors. One irony
is that most equipment that has built-in power line filtering beyond this,
does so because it is trying to keep from radiation HF noise, not keep it
out of the equipment.
II. Why do I NEED/WANT one?
============================
II.a: NEEDS
Unless you suffer from chronic over/under voltages at
your house then chances are you don't really need a power
conditioner, the system will work reliably without it.
Amen, brother.
You may very well find that surge protection is important
to you. Check out the separate "Nigel's Surge Supression Info Sheet".
Every once in a while I see a computer that probably got knocked out by a
power surge. This usuall kills the PC's power supply. I see about one a
year. A surge protector might easily cost more than a new power supply.
Multiply that by all the PC's with unecessary external surge protectors that
could have simply shrugged off the surges they saw, or simply never got hit
by any.
II.b: WANTS
Audio/videophiles WANT power conditioners because they
feel it will improve the quality of their listening or viewing
experience.
Feel would be a good word. A lot of audiophilia is about feeling as opposed
to learning or thinking.
How much of an audible or visible difference a power line
conditioner will make in your world depends on the
following:
1. The quality of your incoming AC power.
2. The quality of your components power supplies.
3. The resolution of your system
(Fix your room acoustics first, then
worry about power line issues)
The point about acoustics is highly relevant. However the idea that there is
audio gear that has that much higher resolution than ordinary gear that it
is that much more sensitive to power is ********. More likely, the high end
gear is improperly designed and lacks the normal levels of rejection of
noise sources that are seen in mid-priced and professional audio gear.
7. Your gullibility
Good point.
An example of exceptional power supply design is found in
much of Krell and Mark Levinson equipment some of which use fully
regulated, fully balanced power supplies.
Actually, just about every piece of audio gear of even modest cost has
fully-regulated, fully-balanced power supplies, for the parts of the
equipment that would benefit from it. The idea that you've got to spend
megabucks to get equipment with a good power supply is total bullocks.
This is a rare thing,
That would be a false claim, providing we can believe that the author is
poorly-informed enough to actually believe what he just wrote.
but any potential benefit from a power conditioner
may be a moot point with this equipment.
Power conditioners are generally a moot point.
Most amplifiers
use unregulated, but highly filtered power supplies,
relying on the incoming AC voltage remaining constant,
and large capacitors to reduce any noise on the line.
Frankly, I would not call the main power supply in a power amp "highly
filtered". Genearlly there is only one stage of capacitive filtering, no
inductors, and no pi-network filtering. Furthermore, load that power amp up
and you'll often find volts of ripple on the main DC power lines in the
power amp. It's the output stage that rejects the ripple and makes the
output of the power amp clean.
There is one exception to this. Power conditioners that
provide balanced outputs may reduce ground loop related
hums, as well as provide a good lowering of the overall
noise floor.
Only an issue with poorly-designed equipment and systems.
snip manufacturer-by-manufacturer sales pitches