[Arny Krueger]

"Bret Ludwig" wrote in message
ups.com
Arny Krueger wrote:
"Powell" wrote in message

"Eeyore" wrote
ons.

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.

The Sola ferroresonant transformer was usually mounted in
the basement so you didn't realize there even was one. I
have salvaged them from torn down gas stations and fast
food joints. They work great, mounted in the basement.

Mine sit in that big "Onan" box that frustrates Powell so much. I only trot
it out for things like specification tests on power amps.

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.

Generally unecessary. The power supplies in good audio
gear can tolerate a wide range of surges.

What you mean is they SHOULD BE able to. Many linear
supplies can't.

Got any test results to share? I have a 25 amp variac and a number of
voltage indicaters including an old RCA two Kill-a-watts.

Generally unecessary. The power supplies in good audio
gear can tolerate a wide range of voltage sources.

See above.

Been there, done that.

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.

We were out for three days two years ago. But under the
circumstances we didn't give a **** about the stereo.

And if you do, you need something that runs off of gas, gasolene, or diesel.


Switchmode supplies should be able to take surges-as
opposed to spikes-very well. Peecee supplies are built to
a purple panda's pussy hair on price. Then the customer
goes ape**** and demands a new computer, and if it's
within warranty the manufacturer gives them one. False
economy.

Well, they can recycle refurb computers well enough to still have a
business.

Power conditioners are generally a moot point.

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.

That's one reason the PA amps you love to extol do not do
that well in high end service. But not the primary one.

I haven't seen a high end or other audiophile amp that was that much
different.

Most traditional solid state power amps have no voltage
regulation and in fact would benefit from regulating at
least up to the driver stage.

Nahh.

OTOH regulating the output
stage linearly does make for a lot more weight and heat,
as big heatsinks are necessary.

There aren't a lot of power amps that have regulated power supplies. The
Dyna 120 was one of them, and there was a Quad. AFAIK both are long out of
production.

Tube amps have much
better short-term energy control at the final stage, or
at least can have, without highly inefficient linear
shunt or pass regulation.

Nahh. Most tube amps have like a 50 uF PS cap at the PS output, which can
store a lot of voltage for its size, because of the 5x higher voltage. So
energy goes up with the square of the voltage and we have 25 times the
energy for a given sized cap.

But, 25*50 is just 1,250, and there are hardly any SS power amps worth
mentioning that have as little as twice that much capacitance in their PSs.
The QSC USA 400 that so many like to **** on has 6,600 uF. So, we're talking
between 2 and 5 times more energy storage, even in pro audio SS amps.

A good tube amp with a remote,
choke filtered supply keeping all AC except the signal
off the chassis is a very impressive thing. It does weigh
a lot (as though I care.)

Tubed amps are a different case because they have less feedback, and
therefore less power supply rejection.

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.

Balanced power is used in most serious recording
facilities today.

There's that catch word, serious.

In fact, the NEC actually had to be
amended to permit 110V balanced power in commercial
faclilties. A simpler way to achieve this, is simply to
use the 220V balanced power already in most American
houses. It appears to be of great benefit, and requires
only that you buy only equipment suited to 220 V
operation. The safety issues with equipment designed for
unbalanced power are those also found when it is used
with 110V balanced power. The power switch and circuit
breaker should break both hot lines, which is usually
easy to do: alternatively wire the box to be on at all
times and use an external switch.

Balanced power is a band-aid. Some people need band-aids though.