"Joe" wrote
I am in need of a power conditioner for my home
recording studio.
Power conditioner is a very generic term.
Nigel's Power Line Conditioner Info Sheet
(C) 2000
V 1.15
This document may be copied so long as it is copied in it's
entirety, including copyright, and so long as it is not posted to
rec.audio.high-end
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.
These devices are still made and they are used to provide voltage regulation
for devices like copiers. 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. I thought
Tice
or Audio Power made a similar device, but I seem to be mistaken. Two good
sources 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.
Today there are many things called a line conditioner, and they are not all
the same. In general a power line conditioner can be everything from a
power strip with surge protection to larger, beefy boxes that do a variety
of things to the incoming AC power.
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.
2. Provide surge protection
3. Provide Under / Over voltage protection
(turns off)
4. Provide Under / Over voltage regulation
(keeps the output voltage constant)
5. Provide power outage protection
(like an Uninterruptable Power Supply)
6. Provide a lower apparent impedance to the source
(like PS Audio, Elgar, etc.)
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, and a
good guage of how much you should be paying for it. If you just spent
$1,300 on a power strip you can pick up with your pinky, you paid too
much. Articles in Hi Fi News and Record Review (a brit mag) in 1998-99
give some insight into building your own.
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.
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.
You may very well find that surge protection is important to you. Check out
the separate "Nigel's Surge Supression Info Sheet".
If you're buying some fancy power line conditioner that is supposed to
include surge protection, ask them if the equipment has been certified to
UL 1449 Second Edition. I have yet to see an audio equipment
"Conditioner" manufacturer that claims surge supression publish any
sort of UL or CSA listing on their web site, so be careful about relying on
them for surge supression. This does not include Monster Cable's strips,
they are primarily a surge supressor, with noise filters added, and are in
fact UL 1449 certified.
II.b: WANTS
Audio/videophiles WANT power conditioners because they feel it will improve
the quality of their listening or viewing experience. 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)
4. The effectiveness & features of the
line conditioner.
5. How much noise the line conditioner itself
actually creates
(a potential problem in a UPS)
6. What frequencies the power conditioner's filtration
is effective at.
7. Your gullibility
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. This is a rare thing, but any potential benefit from a
power conditioner may be a mute point with this
equipment. 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.
II.c: WON'Ts
One thing most line conditioners don't do is fix ground loop problems (i.e.
a loud 60 Hz hum you hear coming from your speakers), in some cases they
can actually make things worse by improving the connection to ground of
your equipment. The ideal way to fix a ground loop problem is to use signal
level isolation transformers between your system and the source of the
problem, which is often the cable TV or a computer connection. Check out:
www.jensentransformers.com
for a variety of safe solutions. Otherwise, if you want to start a fire or
electrocute yourself or your family, use a 2-3 prong adaptor, a.k.a. a
cheater plug.
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.
Also, power conditioners should not be used to substitute for bad electrical
wiring. In some cases a power conditioner may make things worse, drawing
more current and stressing the existing wiring. You should NEVER over fuse
wiring.
III. HTML Links
================
Here is a variety of links to people selling things that go between your
equipment and the incoming AC line.
www.apcc.com
www.audiopower.com
www.accuphase.com
www.belkin.com
www.bestpower.com
www.brickwall.com
www.elgar.com
www.equitech.com
www.furmasound.com
www.monstercable.com
www.psaudio.com
www.surgex.com
www.ticeaudio.com
www.tripplite.com
www.vansevers.com
You should also check the links from
www.stereophile.com which
seem to be pretty exhaustive, and mention many more manufacturer links
to audio related power line products than I do here. Be warned however
that while the list at Stereophile may be more comprehensive than mine,
it's less discriminating, and includes some products I feel provide
particularly poor return on investment.
IV. Products & Technology
==========================
Some products merit special attention in my book, for a variety of reasons.
Monster Cable
=============
Despite having the WORST web site in all of audio regarding technology, with
gross technical and gramatical errors, several people have sent me e-mails
defending their power strips, claiming they made improvements in picture or
video quality. Heck if I know, but you might want to, they're not too
expensive.
Panamax
=======
Panamax gets special because they do have complete A/V surge protection
solutions their parts quality does not usually merit what they charge, like
$99 for a standard surge strip, and I've read of reliability and warranty
problems online, so you should check the archives at
www.deja.com. In my opinion APCC, Triplite and Belkin all give you
more surge protection/dollar than Panamax.
The Panamax DBS+ I have (got a deal on it) has failed to protect my two
satelite receivers from wind related static discharge , so I'm not too happy
with them these dayas.
Brickwall & Zerosurge
=====================
Working on a completely different principle of surge protection than MOV
based surge protectors are the models from Brick Wall and
ZeroSurge. They are basically single pole low pass filters ( a good thing )
for your power lines. The claimed response is -3db at 3 kHz. This
effectively limits the maximum Volts/Second. When a surge hits, it becomes
a 2nd and 3rd order low pass filter. Surgex also OEM's these devices, or
licenses the technology.
This low start point for their noise filtration puts them into both my Line
Conditioner sheet as well as my Surge Protection sheet.
Audo Power & Tice
=================
Moving closer to the ideal of a power line conditioner are the ones that
use isolation transformers. These have a much better capacity to remove
audible power line noise than mere surge strips. Audio Power & Tice have
a variety of products you should take a listen to, if you can get past
Tice's
voodoo web pages (i.e. their Q&A section). Note that not all these
products use isolation transformers, so check to be sure what you're
getting.
Richard Gray's Power Company
============================
Tremendous hype on their web site is parroted almost word for word by
dealers and customers. Their web site and "Grey Paper" fails to make any
truly technical statements about what the product does and IMHO they offer
poor return on investment, considering the parts that actually go into them,
and that they sell for around $700. I would encourage people to either
spend another $300 for a PS Audio unit, or spend less for something from
Furmasound or Equitech, or even getting a power conditioner (not a UPS)
from APC or Tripp Lite instead of buying a product from this company.
PS Audio
========
New are the Power Plant models from PS Audio. PS Audio has taken the
high road, and said electrical bill be damned! We'll get clean power no
matter the cost. The Power Plant models are basically power amplifiers
that re-create the 115 Volt AC signal at their output. They are perhaps the
most ambitious designs I've seen so far and again have some good ideas
behind them. Their prices seem very reasonable, considering how much
goes into one and the current offerings of power conditioners in the
market, and they certainly should be able to meet their twin goals of:
Greatly reducing apparent power line impedance
- AND -
Greatly reducing power line noise and distortion
The technology used may very well be the best at doing those two things
in combination.
Since the Power Plants are essentially class AB amplifiers they are no
better than 50% efficient, so expect it to add additional heat and
electrical current draw to your electric circuit, which is something to pay
attention to if you're close to being overloading it already. On the other
hand, using a linear (AB) amplifier stage removes the likelihood of
more digital noise being introduced into the 60 Hz waveform it
generates.
If the PS Audio units don't have enough current capacity, consider the
products from Elgar, sweeet....way expensive! If you have money to burn,
perhaps you should consider an Elgar as a pre-conditioner, and use a PS
Audio unit for your source components only.
Other equipment manufacturers should also take note that unlike many sites
PS Audio's web site was delightfully free of bovine scatalogical samples.
Chang Lightspeed
================
Chang Lightspeed need comments on because of their on-line
advertising which demonizes coils & transformers. They're right about
small, poorly designed coils actually increasing the power line
impedance, however what they fail to note is that by going coilless their
conditioners may very well not be able to remove any power line noise
within the audible spectrum. This noise is the most important to
audiophiles are concerned with as it has the best chance of being
propagated through the power supplies of the equipment and finally
to our ears. Perhaps this is why their on-line advertising mentions
RFI/EMI noise reduction so much, and makes no mention of audio
frequency noise reduction. Coil impedance can be overcome by using
bigger and better inductors.
Does anyone know how much these puppies weigh? I bet you they're
lighter and are less expensive to manufacture than comparative
products from manufacturers who DO use coils in their designs.
Uninterruptable Power Supplies
==============================
A UPS is a must for anyone doing serious computer work, but it's benefits
for audiophiles will vary. If you're going to try a UPS to improve the
sound / picture quality then avoid the standby kind, which have a 2-4 ms
lag before they turn on. Get one labeled "line interactive."
Because UPS's are designed for computers they usually pay little attention
to how much grunge is coming out when they generate the output
waveform, which could in turn easily make your system sound worse,
not better. The solution is to make sure the output of your UPS is a sine
wave, with the lowest possible distortion and noise. So, avoid "stepped
aproximation" and look for "pure sinewave" output.
Lastly, most UPS have a relatively loose voltage regulation. For example,
as the input voltage varies from 90 to 145 volts the UPS will output from
105 to 125 volts. It's a smaller variation than what's coming in, and it's
certainly better than any passive conditioners like Audio Power or Tice but
it's certainly not the best technology could do if money were no object.
Radio Shack
===========
Yes, RS can be an audiophiles best friend, especially when he/she is
looking for a $20 voltage meter. If you think you have a chronic voltage
problem at your home or listening room outlets go get a meter and find
out. If it's bad enough, perhaps you should start with a phone call to your
electrical company and/or electrician before getting a voltage conditioner.
V. Cheap Tweaks for the Dangerously Inclined
=============================================
One potential improvement audiophiles can make, fairly easily if they are
electronically and dangerously inclined, is to increase the power supply
filter capacitance. You can do this both by replacing the current storage
capacitors to higher values of capacitance (and equal or better voltages)
and also by adding storage capacitance across the maximum + and -
voltage rails of the device (make sure the capacitor's voltage rating is
greater than the difference between the + and - rails, of course). While
we're going there, consider also replacing the filter caps with less
inductive versions if possible such as caps from Sanyo or Panasonic
(I think, sorry, it's been a while since I was opening data books so check
this out yourself) as well as adding polypropelyne or polystyrene
capacitors of equal or greater voltage rating in parallel with any upgrades
you do.
Be careful with how much capacitance you add, adding capacitance
increases the turn on (inrush) current and may over-stress the bridge
rectifier. Of course, the fix for this is to add a bigger rectifier so you
can get
more power! (Grunt grunt!) And if you fry your transforer too, well that can
be fixed as well!
This little tweak alone can greatly increase the S/N ratio of many mass
market electronic devices far more than other tweaks, such as new power
cables. If you already have a very good power supply it won't matter much
as if you didn't (i.e. it will make a bigger difference for mass market Sony
or Yamaha than Krell or Mark Levinson).
I won't go into any more detail than this, if you have to ask chances are
you shouldn't be in there anyway. Oh, yeah, and as always, if you're an
idiot and hurt yourself or your equipment don't call me, have your mama
call me so I can tell her what a dufus you are.
VI. Closing Comments
=====================
I don't mean to exclude anyone, so if I missed you or a product you feel
deserves special mention send an e-mail to nigel_tufnel@my- deja.com
and I'll add it onto this growing and improving list.
As always, thoughtful, informative discussions are encouraged,
corrections are gladly accepted, and flames may be sent to
[email protected]. It's your ears, eyes and wallet you're trying to
please. Advice from anyone is a good way to start but it's your hard
earned dollar so you should always be the final judge of a products
worth.
