[[email protected]]

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker?
The run to where the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..

[Sonnova]

On Wed, 1 Oct 2008 13:30:05 -0700, wrote
(in article ):

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker?
The run to where the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..


I can't see where running a dedicated line from your utility box to your
listening room will do any good unless you are afraid that your stereo
equipment is taxing the existing wiring to somewhere near its current limit.
The reason why I say this is because it's still the SAME mains line from the
primary house feed. The three-phase line comes into the house where all three
phases feed things such as electric stoves/ovens and clothes dryers with
so-called 220 volts. At the main breaker, each phase is split off into the
feeder circuits (each with it's own 15 or 20 amp breaker/fuse in most US
homes) with 110 volt standard current. Except for the fact that half the
house is usually wired on one phase and the other half is wired on the second
phase, there is no isolation between the branches. So, unless your house only
uses one of the 110 phases to supply all the 110 house current, and you tap
into the other, unused one for your dedicated audio run, you have no real
isolation from the grunge found on a normal house current line at all. Even
so, the other phase will be shared with all other households and businesses
that exist on your side of the nearest pole-mounted, electric company
transformer, so even if you don't use the other phase, rest assure, somebody
in your neighborhood does and their noise/interference is YOUR
noise/interference.

What I did was different. I found a huge isolation transformer (weighs close
to 100 pounds) of the kind used in hospitals and scientific labs at a
going-out-of-business electronics surplus store for $75. It is 110 to 110 and
the output end of the transformer is fitted with a standard hospital-style
wall plate and two standard hospital grade 3-prong outlets. There are filters
made up of oil-filled capacitors in-line with the windings on both the
primary and the secondary sides. These are built-into the end "bells" of the
transformers. The primary side is plugged into the wall, and my stereo system
is plugged into the secondary side. The 'theory' is that with so much 60Hz
"iron" and so many windings, that the transformer serves as a low-pass
filter. 60 Hz power is transferred, but any frequencies, such as RF noise or
other grunge riding on the AC that are much above 60 Hz are attenuated. A
look with an oscilloscope verifies that the secondary side of the transformer
is MUCH cleaner looking than the primary. Not even compressor turn-on spikes
like the refrigerator or air conditioner get through!

Results? I haven't noticed any difference in the sound of my system with or
without this transformer, in spite of the cleaner mains. I leave it in the
system, because it doesn't really hurt anything, But I think this power
conditioning and the $400 IEC mains cords and the like that go with them are
a bunch of audiophile hooey. YMMD.

[Mike Gilmour[_2_]]

"Sonnova" wrote in message
...
On Wed, 1 Oct 2008 13:30:05 -0700, wrote
(in article ):

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker?
The run to where the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..


I can't see where running a dedicated line from your utility box to your
listening room will do any good unless you are afraid that your stereo
equipment is taxing the existing wiring to somewhere near its current
limit.
The reason why I say this is because it's still the SAME mains line from
the
primary house feed. The three-phase line comes into the house where all
three
phases feed things such as electric stoves/ovens and clothes dryers with
so-called 220 volts.

I don't know if this is an American way but normally UK houses are fed with
a single phase supply so the three-phase line does not enter the house in
the average domestic dwelling. However this does happen in large
flat/apartment complexes such as highrises where three-phase is used, the
three separate phases is distributed for equal loading throught the complex.
A similiar phase distribution happens between numbers of houses/streets.

Normally your system would be fed from one phase only. Taking system
supplies from two separate phases can cause earth loop related problems as
any pro-sound engineer who does sound reinforcement duties will tell you.

I have a number of heavier core dedicated feeds from the consumer unit
direct to my system to maintain tight supply regulation. For example my NRG
amplifer feeding the bass speakers has a 3000VA toroidal transformer feeding
supplies with a capacitance in excess of 100,000 microfarads. I believe
isolation of supplies can also largely free up the supply from locally
generated noise. Remember digital devices also distribute noise to some
degree - this is why you see ferrite blocks on some cables in your computer
wiring. It's quite instructional to investigate the amount of noise on your
supply line, I understand there is a device available so you can actually
hear that noise!
My own analysis showed noise plus regular timed spikes, finally traced to
induced noise from a farmers electric fence 1/3 mile away!

I believe there are benefits from dedicated supplies where the combined
system load is high. A number of my friends who have installed dedicated
supplies have said there is a sonic improvement - but there again it's not
an A-B comparison. Personally I like to keep the supply as tight as
possible, i.e. nothing with any marked impedance in series with the supply,
filtering only from supply to ground.


At the main breaker, each phase is split off into the
feeder circuits (each with it's own 15 or 20 amp breaker/fuse in most US
homes) with 110 volt standard current. Except for the fact that half the
house is usually wired on one phase and the other half is wired on the
second
phase, there is no isolation between the branches. So, unless your house
only
uses one of the 110 phases to supply all the 110 house current, and you
tap
into the other, unused one for your dedicated audio run, you have no real
isolation from the grunge found on a normal house current line at all.
Even
so, the other phase will be shared with all other households and
businesses
that exist on your side of the nearest pole-mounted, electric company
transformer, so even if you don't use the other phase, rest assure,
somebody
in your neighborhood does and their noise/interference is YOUR
noise/interference.

What I did was different. I found a huge isolation transformer (weighs
close
to 100 pounds) of the kind used in hospitals and scientific labs at a
going-out-of-business electronics surplus store for $75. It is 110 to 110
and
the output end of the transformer is fitted with a standard hospital-style
wall plate and two standard hospital grade 3-prong outlets. There are
filters
made up of oil-filled capacitors in-line with the windings on both the
primary and the secondary sides. These are built-into the end "bells" of
the
transformers. The primary side is plugged into the wall, and my stereo
system
is plugged into the secondary side. The 'theory' is that with so much 60Hz
"iron" and so many windings, that the transformer serves as a low-pass
filter. 60 Hz power is transferred, but any frequencies, such as RF noise
or
other grunge riding on the AC that are much above 60 Hz are attenuated. A
look with an oscilloscope verifies that the secondary side of the
transformer
is MUCH cleaner looking than the primary. Not even compressor turn-on
spikes
like the refrigerator or air conditioner get through!

Results? I haven't noticed any difference in the sound of my system with
or
without this transformer, in spite of the cleaner mains. I leave it in the
system, because it doesn't really hurt anything, But I think this power
conditioning and the $400 IEC mains cords and the like that go with them
are
a bunch of audiophile hooey. YMMD.

[Sonnova]

On Thu, 2 Oct 2008 06:00:04 -0700, Mike Gilmour wrote
(in article ):

"Sonnova" wrote in message
...
On Wed, 1 Oct 2008 13:30:05 -0700, wrote
(in article ):

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker?
The run to where the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..


I can't see where running a dedicated line from your utility box to your
listening room will do any good unless you are afraid that your stereo
equipment is taxing the existing wiring to somewhere near its current
limit.
The reason why I say this is because it's still the SAME mains line from
the
primary house feed. The three-phase line comes into the house where all
three
phases feed things such as electric stoves/ovens and clothes dryers with
so-called 220 volts.

I don't know if this is an American way but normally UK houses are fed with
a single phase supply so the three-phase line does not enter the house in
the average domestic dwelling. However this does happen in large
flat/apartment complexes such as highrises where three-phase is used, the
three separate phases is distributed for equal loading throught the complex.
A similiar phase distribution happens between numbers of houses/streets.

In the US, we have a mix of 220 and 110 volt main devices. We do not power
our light bulbs, televisions and electric razors on 220 volts. Just our
electric stoves and our clothes dryers, big central air-conditioning units
and heat pumps/oil furnace/hot water systems.

Normally your system would be fed from one phase only. Taking system
supplies from two separate phases can cause earth loop related problems as
any pro-sound engineer who does sound reinforcement duties will tell you.

That's not what I said. Houses use one of the other for 110 delivery, and
often power different parts of the house from different phases. The only
place where both phases are used are on 220 volt appliances where the phases
are 110-0-110 = 220 volts.

I have a number of heavier core dedicated feeds from the consumer unit
direct to my system to maintain tight supply regulation. For example my NRG
amplifer feeding the bass speakers has a 3000VA toroidal transformer feeding
supplies with a capacitance in excess of 100,000 microfarads. I believe
isolation of supplies can also largely free up the supply from locally
generated noise. Remember digital devices also distribute noise to some
degree - this is why you see ferrite blocks on some cables in your computer
wiring. It's quite instructional to investigate the amount of noise on your
supply line, I understand there is a device available so you can actually
hear that noise!
My own analysis showed noise plus regular timed spikes, finally traced to
induced noise from a farmers electric fence 1/3 mile away!

I believe there are benefits from dedicated supplies where the combined
system load is high. A number of my friends who have installed dedicated
supplies have said there is a sonic improvement - but there again it's not
an A-B comparison. Personally I like to keep the supply as tight as
possible, i.e. nothing with any marked impedance in series with the supply,
filtering only from supply to ground.

I simply don't believe that very much of this grunge can get through the AC
to DC conversion process that happens in the power supply of any audio
component. Most Hi-end components are over-designed in this regard anyway. I
suspect that if enough high frequency grunge to affect the sound actually got
through a component's power supply, that you could see it under no-signal
conditions on an oscilloscope, but more importantly, you would see it in your
TV picture! That you don't, shows that the effect of noise on the line is
miniscule.

[Mike Gilmour[_2_]]

"Sonnova" wrote in message
...
On Thu, 2 Oct 2008 06:00:04 -0700, Mike Gilmour wrote
(in article ):

"Sonnova" wrote in message
...
On Wed, 1 Oct 2008 13:30:05 -0700, wrote
(in article ):


I have a number of heavier core dedicated feeds from the consumer unit
direct to my system to maintain tight supply regulation. For example my
NRG
amplifer feeding the bass speakers has a 3000VA toroidal transformer
feeding
supplies with a capacitance in excess of 100,000 microfarads. I believe
isolation of supplies can also largely free up the supply from locally
generated noise. Remember digital devices also distribute noise to some
degree - this is why you see ferrite blocks on some cables in your
computer
wiring. It's quite instructional to investigate the amount of noise on
your
supply line, I understand there is a device available so you can actually
hear that noise!
My own analysis showed noise plus regular timed spikes, finally traced to
induced noise from a farmers electric fence 1/3 mile away!

I believe there are benefits from dedicated supplies where the combined
system load is high. A number of my friends who have installed dedicated
supplies have said there is a sonic improvement - but there again it's
not
an A-B comparison. Personally I like to keep the supply as tight as
possible, i.e. nothing with any marked impedance in series with the
supply,
filtering only from supply to ground.

I simply don't believe that very much of this grunge can get through the
AC
to DC conversion process that happens in the power supply of any audio
component. Most Hi-end components are over-designed in this regard anyway.
I
suspect that if enough high frequency grunge to affect the sound actually
got
through a component's power supply, that you could see it under no-signal
conditions on an oscilloscope, but more importantly, you would see it in
your
TV picture! That you don't, shows that the effect of noise on the line is
miniscule.

I'm not quite so sure that RF doesn't have some small effects on the noise
of the system. For example I initially had a RF related problem with my NRG
amplifier which has a very wide bandwidth for an AF amplifier. Whilst using
open core Cogan Hall cables some input RF problems occurred that caused the
mute mode to cycle. By further investigation I found that the input
amplifier board had an HF roll off filter with a selectable cut-off
frequency which could be set to roll off all input signals above either 200
KHz or 3 MHz at 6 dB/octave. Setting it to the lower bandwidth cured the
problem. I had long talks about this with the then VP of NRG Chris Ludwig
who subsequently sent me all the workshop manuals and separate large
schematics free of charge.

Furthermore I found there is a slight reduction of background noise
(preamplifier gains fully up) when using a parallel local ground, i.e. a
long copper rod with wire radials into the soil connected to the system via
a copper strip (by background involved RF engineering) - this could be
easily demonstrated by disconnecting/reconnecting. Supply loop tests showed
the existing supply ground was satisfactory so I deduce this must only be HF
related however small. There are no transmitters in the local area so I
assume its possibly due to RF signalling on mains as used by utilities and
others.

[Will Prints]

On Wed, 01 Oct 2008 20:30:05 +0000, wrct wrote:

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker? The run to where
the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..

I live in a house that has had (re)construction in every year from 1951
onward. We now have at least a dozen "dedicated circuits" in the house.
The background noise level in the audio system is quite low, and was not
improved by putting the audio on a separate circuit. What /did/ help
eliminate a tiny amount of electrical crackle and other random hisses was
putting the computers in a separate room behind the garage on a separate
circuit with noise rejection between the computers and everything else in
the house.

george
www.georgeflanagin.com

[[email protected]]

I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker? The run to where
the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..

I live in a house that has had (re)construction in every year from 1951
onward. We now have at least a dozen "dedicated circuits" in the house.
The background noise level in the audio system is quite low, and was not
improved by putting the audio on a separate circuit. What /did/ help
eliminate a tiny amount of electrical crackle and other random hisses was
putting the computers in a separate room behind the garage on a separate
circuit with noise rejection between the computers and everything else in
the house.

How did you achieve the latter "noise rejection" aside from the physical
distance?

I had already planned to have computer and audio gear on seperate
circuits with this in mind. In addition I chose existing lines that
have minimal parallel runs between them and physically separated as far
as possible.

What else might you suggest?

Thanks.

[Peter Wieck]

OK, a few things, and please forgive my tendency to lecture.

a) ANY residential 110/220 (more like 120/240 these days anyway - and
that is a long and separate story) system is Two-Wire SINGLE PHASE
current. The neutral(ground) takes half the phase to make half the
voltage from each LEG of the SINGLE phase.

b) A dedicated line is always useful as electronics don't like voltage
sags - and unless you know exactly what else is being shared on any
given line, there may well be a sag if some device kicks in such as a
vacuum cleaner, air-conditioner, hair-dryer or similar.

c) Most sources of noise are below-the-horizon items such as defective
fluorescent lamp ballasts (and this is becoming more and more of an
issue with the increasing use of CFL-type lamps), electronic light
dimmers, poorly shielded appliance motors, *some* switching power-
supplies (mostly for computers) and the like. Again, this is a rather
difficult problem that a dedicated line addresses only in small part -
but that part can be the difference.

d) Then, there are ground-loops and the associated hum. A dedicated
line and careful set-up helps with this greatly - but mostly it is the
careful set-up part that matters.

Cutting to the chase: A dedicated line (at least 20A, #12 wire) can't
hurt and will avoid some issues. Purchase good-quality name-brand CFL
lamps, dimmers and such. Pick-by-direct-test the leg that DOES NOT
carry the hair-dryer, space-heater, or whatever if you can.

Peter Wieck
Melrose Park, PA

[Doug McDonald[_3_]]

Peter Wieck wrote:
OK, a few things, and please forgive my tendency to lecture.

a) ANY residential 110/220 (more like 120/240 these days anyway - and
that is a long and separate story) system is Two-Wire SINGLE PHASE
current. The neutral(ground) takes half the phase to make half the
voltage from each LEG of the SINGLE phase

Huh? At least all the places in the USA I have ever lived,
th 117 nominal volts line is single sided: one side is essentially
grounded ( most I ever measured was 8 volts off ground) and the
other is 117 volts away.

Where I work we have nominal "200 odd" volts lines, two wires plus
ground. The two non grounded phases are 117 volts off ground, and
120 degrees apart phase. Thus it is not 234 volts, but 203.

Doug McDonald

[Sonnova]

On Mon, 6 Oct 2008 15:36:27 -0700, Peter Wieck wrote
(in article ):

OK, a few things, and please forgive my tendency to lecture.

a) ANY residential 110/220 (more like 120/240 these days anyway - and
that is a long and separate story) system is Two-Wire SINGLE PHASE
current. The neutral(ground) takes half the phase to make half the
voltage from each LEG of the SINGLE phase.

b) A dedicated line is always useful as electronics don't like voltage
sags - and unless you know exactly what else is being shared on any
given line, there may well be a sag if some device kicks in such as a
vacuum cleaner, air-conditioner, hair-dryer or similar.

Unfortunately, any circuit fed from the same house feed is on the same
circuit and is only isolated from the rest of the house load by a dedicated
breaker or fuse and these do nothing to isolate the separate circuit from the
rest of the house and its noise sources.

c) Most sources of noise are below-the-horizon items such as defective
fluorescent lamp ballasts (and this is becoming more and more of an
issue with the increasing use of CFL-type lamps), electronic light
dimmers, poorly shielded appliance motors, *some* switching power-
supplies (mostly for computers) and the like. Again, this is a rather
difficult problem that a dedicated line addresses only in small part -
but that part can be the difference.

d) Then, there are ground-loops and the associated hum. A dedicated
line and careful set-up helps with this greatly - but mostly it is the
careful set-up part that matters.

Cutting to the chase: A dedicated line (at least 20A, #12 wire) can't
hurt and will avoid some issues. Purchase good-quality name-brand CFL
lamps, dimmers and such. Pick-by-direct-test the leg that DOES NOT
carry the hair-dryer, space-heater, or whatever if you can.

Not bad advice.

[Peter Wieck]

On Oct 6, 11:43*pm, Doug McDonald wrote:
Peter Wieck wrote:
OK, a few things, and please forgive my tendency to lecture.

a) ANY residential 110/220 (more like 120/240 these days anyway - and
that is a long and separate story) system is Two-Wire SINGLE PHASE
current. The neutral(ground) takes half the phase to make half the
voltage from each LEG of the SINGLE phase

Huh? At least all the places in the USA I have ever lived,
th 117 nominal volts line is single sided: one side is essentially
grounded ( most I ever measured was 8 volts off ground) and the
other is 117 volts away.

Where I work we have nominal "200 odd" volts lines, two wires plus
ground. The two non grounded phases are 117 volts off ground, and
120 degrees apart phase. Thus it is not 234 volts, but 203.

Doug McDonald

OK - lemme clarify, while keeping in mind that I am in the
Philadelphia (PECO) service area. There are four (4) sorts of
electrical services available on a GS/RS (General Service, meaning
already transformed to operating voltages):

Residential (Type RS): Nominal 110/220 *Single Phase*, three-wire
service (HGH).

Commercial Three-phase/Three-Wire (Delta) Service at some nominal
voltage as low as 110/208. HHH This is not typical. Most Delta-
supplied services are at primary voltages (3300V or higher) for those
commercial customers who transform on-site. Delta as one less heavy
conductor is required.

Commercial Three-phase/Four-Wire (Y) service, at 110/208 or higher.
HHHG-in-the-center. This is the typical commercial service.

Commercial *TWO-phase*/Four Wire service at 220/440 H-G-G-H. This
service is used in a very, very few locations with elevator equipment
dating back to the 1920s, before 3-phase was available in the region
and before reliable motor-generator systems were developed - primarily
for elevator installations and/or large absorbtion HVAC systems. But,
it is still extant in this area (and Baltimore, MD), confined to a
small section of Center City Philadelphia at this time.

Hence the need to distinguish residential service as *single* phase, 3
wire. At my panel in the basement, I am getting 117/234 at the main
lugs. Go figure.

Peter Wieck
Melrose Park, PA

[Arny Krueger]

wrote in message


I'm setting up a new listening space and considering
having a circuit devoted to it.

Seems like a good idea. You might even want to have two circuits for it, one
for the A/V gear and one for the lighting.

Is there any advantage in installing a new breaker and
circuit or just tapping into an existing one right after
the breaker?

Breakers are very cheap, especially if there are spare slots in the circuit
panel. However working at this level is a job for professionals, or amateurs
whose knowlege of legal requirements and accepted practice transcends what
you can reasonably expect from an audio-centric news group.

For one thing, you don't want to overload an existing circuit. And, if you
are fooling around in your listening room and manage to trip a breaker, you
don't want to affect other parts of the house, especially mission-critical
circuits for heating and lighting.

The run to where the equipment will be is short from the
circuit box.

Makes things easy, but has little to do with the price of Tea in Boston.

In terms of electrical isolation does either version have
an advantage?

Now that you're thinking about the wiring in your breaker box, can't you see
how circuits in a house are very poorly isolated from each other, given all
those heavy, short pieces of copper that tie things together?

The limited kind of isolation that they provide has everything to do with
convenience and safety and almost nothing to do with sound quality, given
that they are properly designed and properly implemented.


The existing line I can tap into has only
lighting and similar low load things plugged into it so
there is really no concern for motor startup surges and
other noise sources..

OTOH, modern houses have dimmable lighting, and dimmers can put EMI on a
power circuit and even whole house like little since the days of oil burner
ignition transformers.

[Peter Wieck]

Mpfffff.... Please note the interpolations:

On Oct 13, 9:13*am, "Arny Krueger" wrote:
wrote in message



I'm setting up a new listening space and considering
having a circuit devoted to it.

Seems like a good idea. You might even want to have two circuits for it, one
for the A/V gear and one for the lighting.

???? What "lighting" is there in AV gear? The point being that a
dedictated circuit is a dedicated circuit - only the AV gear is
connected to it. One would have to design the entire household wiring
system from the git-go to isolate lighting from everything else - as
well as violate at least half-a-dozen code regulations for balanced
loads and so forth. This is no small thing. Any electrician worth his
or her salt will "balance the load" before leaving any sort of
installation that involves either a new service or adding circuits to
an existing service. Further, that electrician will ask meaningful
questions of the householder along these lines, as well as "walk the
house" to determine potential loads. And ALWAYS some lighting on both
legs of the circuit so as a leg-failure will not leave a house
entirely in the dark. Most very good electricians refine this to the
point of making sure that every room (especially kitchens) have
receptacles from both legs available, and that ceiling lighting is on
a different leg than receptacles (and circuits) in each room. Several
rooms may share circuits, but at least two per room. In my day, my
boss required that of the four walls in a room, one pair was on one
circuit, one pair on the other, and ceiling lighting a third - when
this was possible. This made three circuits per room, three rooms per
circuit-set.

Is there any advantage in installing a new breaker and
circuit or just tapping into an existing one right after
the breaker?

Breakers are very cheap, especially if there are spare slots in the circuit
panel. However working at this level is a job for professionals, or amateurs
whose knowlege of legal requirements and accepted practice transcends what
you can reasonably expect from an audio-centric news group.

Breakers are cheap, especially cheap breakers in cheap panels. And
unless slots are cut for twins with none already installed, an open
slot is the _only_ legitimate way to add a circuit. If one has a
proper AC ammeter and knows how to use it, it *is* always possible to
combine existing circuits to free up a slot - but this is bad practice
for any number of reasons. Apart from all that, installing a dedicated
circuit is not at all rocket science although full compliance with the
niceties of the NEC is not quite so simple. Note that if your
electrical panel is already full, more than say.... 20 years old, and
you have the full complement of modern appliances, AC unit(s) and so
forth, you may already be at its practical and safe limits. And you
may already be experiencing voltage sags.

For one thing, you don't want to overload an existing circuit. And, if you
are fooling around in your listening room and manage to trip a breaker, you
don't want to affect other parts of the house, especially mission-critical
circuits for heating and lighting.

Then it would not be a 'dedicated circuit', would it?

The run to where the equipment will be is short from the
circuit box.

Makes things easy, but has little to do with the price of Tea in Boston.

In terms of electrical isolation does either version have
an advantage?

Now that you're thinking about the wiring in your breaker box, can't you see
how circuits in a house are very poorly isolated from each other, given all
those heavy, short pieces of copper that tie things together?

"Isolation" is not the correct term in any case. I believe by
intuition that the OP is looking for less noise (already addressed in
part) and perhaps cleaner power (also addressed in part). Now, the OP
could invest in a power conditioner that consists of a CV & Isolation
transformer, capacitor bank and so forth. Not cheap and kinda-sorta
silly as most good equipment (at least as should be discussed here)
does a more than adequate job of conditioning internally within what
is ordinarily considered safe operating conditions. But if the
environment is already very noisy those noise sources cannot be
eliminated, a legitimate option.

The limited kind of isolation that they provide has everything to do with
convenience and safety and almost nothing to do with sound quality, given
that they are properly designed and properly implemented.

As long as one understands that fuse (and circuit breakers) are
designed to protect real-estate and not the equipment they serve. That
would be the point of the exercise as it would require heroic (and
expensive) measures to give a truly noise-free circuit. TrippLite
makes a bunch of such systems - expect to pay $300 or more, much more
if your system could pull 10 amps or more.

The existing line I can tap into has only
lighting and similar low load things plugged into it so
there is really no concern for motor startup surges and
other noise sources..

Not a dedicated circuit in this case - and therefore it won't give any
discernable benefit.

OTOH, modern houses have dimmable lighting, and dimmers can put EMI on a
power circuit and even whole house like little since the days of oil burner
ignition transformers.

Oil Burner ignition transformers are still at-issue in some cheap
guns. Most are shielded these days, but continuous arc-ignition still
exists. And the some systems use intermittent ignition - which can
still be noisy under some conditions, but as the occasional *POP*
rather than the typical continuous buzz when in operation.

Peter Wieck
Melrose Park, PA

[jamesgangnc]

Don't worry about it. You will not see a difference. The circuits all tie
together at the breaker box so there is no isolation. The really major
loads that would cause voltage drop on start up are already on other
circuits.

wrote in message
...
I'm setting up a new listening space and considering having a circuit
devoted to it.

Is there any advantage in installing a new breaker and circuit or just
tapping into an existing one right after the breaker?
The run to where the equipment will be is short from the circuit box.

In terms of electrical isolation does either version have an advantage?
The existing line I can tap into has only lighting and similar low load
things plugged into it so there is really no concern for motor startup
surges and other noise sources..

[Arny Krueger]

"jamesgangnc" wrote in message


Don't worry about it. You will not see a difference.
The circuits all tie together at the breaker box so there
is no isolation. The really major loads that would cause
voltage drop on start up are already on other circuits.

Good point. The electrical isolation between electrical circuits in
residences is very low.

For example, well-known line-based signaling applications like X10
whole-house controls won't work if there is appreciable isolation between
circuits.

I've seen X10 not work in large buildings where there are tiers of
electrical distribution panels that are widely separated.