Dedicated 240V line

[Guest]

Archived from groups: rec.audio.high-end (More info?)

OK, I'm learning a little about residential electrical service in the US and
I understand you
can have the 240 line hooked up directly. Presumably that should give you a
cleaner signal,
but the problem is your gear has to be wired to handle it. Most gear I'm
aware of (thinking
mostly of amps) have to be wired that way internally (no simple switch like
my PC power
supply.)

Now I was looking at this product
http://www.hometheaterhifi.com/volume_8_4/smart-theatre-gc120-11-2001.html
Apparently what that thing does is balance the line for 120v like it would
be in a dedicated line
of 240v (if I read that right.) I'm not interested in paying a grand for
that when I can get it in
the line much cheaper. But down at the bottom of the article it says

"In North America, 240 Volts is provided as a balanced circuit to our homes:
two 120
Volt legs out of phase with each other (our 120 Volt outlets come off of one
of the two
legs). For the ultimate in balanced AC, Smart will be introducing a
variation on the
GC120 which will take the balanced 240 Volts AC at your home's entrance
panel, and
pass it on as balanced 120 Volts AC, tapping into CMR of noise before the
GC120."

Presumably this would still be very expensive. So my question is, is there
some
reasonably priced product that would take 240v from a dedicated line and
step it
down to 120V for use with standard equipment, still getting the benefits of
the
balanced line?

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Why would you want to do this? Unless you have very atypical power at
your house or very poorly designed power supplies in your equipment,
you will be wasting your time and money. The link describes what is
basically expensive snake oil with very dubious technical claims. You
might want to invest in a surge protector to protect your equipment if
that is what your after.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

The damning fact that should have shouted in your face - they make
claims without any numbers. Where do they put any numbers or define
'dirty electricity'. They do not. They are lying by telling half
truths. Even worse, somehow this filter (and it is apparently nothing
more than a filter) will stop what three miles of non-conductive air
could not. Somehow there is an imbalance in 120 volt AC electricity
(because it is supposed to be unbalanced).

As best I can tell from the description, it is a series mode
protector. A filter doing what must already be inside the power
amplifier. All this for $1000?

Other series mode protectors for less money are Zerosurge, Brickwall,
and Surgex. However even these will not stop destructive transients.
But again, numbers also beg that you first learn of the many types of
transients.

Also irresponsible is a following recommendation for a plug-in
protector; that also costs so much money for ineffective protection.
The plug-in protector is not for noise, harmonics, or other 'imbalance'
problems. The plug-in protector simply claims to protect from
transients that are typically not destructive to power amps.

Start by identifying which electrical events you have a problem with.
The typical hardware destructive transient seeks earth ground
destructively through electronics. Effective protection means a 'whole
house' protector earths that transient before it can even enter the
building. No earth ground (such as with plug-in protectors) means no
effective protection.

What else should be eliminated to protect the power amp? Without an
answer to that question, one should not be advocating products such as
surge protectors or that product from www.hometheaterhifi.com­.

Meanwhile, running 240 volts to an appliance designed for 120 volts
could create problems. The system is designed assuming one side of the
AC power is at voltages same as the neutral. If interconnected to
other electronics, then undersireable ground loops could be created.
But again, what is that 240 volt 'balancing' electronics doing. The
article tells us nothing; classic of lying by telling half truths.

jeffc wrote:
> OK, I'm learning a little about residential electrical service in the US and
> I understand you can have the 240 line hooked up directly. Presumably
> that should give you a cleaner signal, but the problem is your gear has
> to be wired to handle it. Most gear I'm aware of (thinking mostly of
> amps) have to be wired that way internally (no simple switch like my PC
> power supply.)


> Now I was looking at this product
> http://www.hometheaterhifi.com­/volume_8_4/smart-theatre-gc12­0-11-2001...
> Apparently what that thing does is balance the line for 120v like it would
> be in a dedicated line of 240v (if I read that right.) I'm not interested in
> paying a grand for that when I can get it in the line much cheaper. But
> down at the bottom of the article it says

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

"w_tom" <w_tom1@usa.net> wrote in message
news:dabkj602msn@news2.newsguy.com...
> The damning fact that should have shouted in your face - they make
>claims without any numbers. Where do they put any numbers or define
>'dirty electricity'. They do not. They are lying by telling half
>truths.... Meanwhile, running 240 volts to an appliance designed for 120
>volts
>could create problems.

Did you actually read what I wrote, or did you just read the web site and go
off on another crusade of yours? I don't want that device. I want a
balanced line. I don't want 240v. Of course plugging a 120v device into a
240v line is a bad idea. If you go back and read what I wrote you'll see
this is all spelled out. If you have any insight into my actual question
I'd appreciate it.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

Why do you want a balanced power? Do you have a specific noise problem?
While balanced signal sources are extremely effective for reducing
noise, the same cannot be said for power sources though there may be
some advantages. You might do a search in rec.audio.pro for balanced
power and check out recommendations and how effective balanced power
sources are without the snake oil.

 

[Guest]

Archived from groups: rec.audio.high-end (More info?)

<imtekms@yahoo.com> wrote in message news:daccq70gc5@news2.newsguy.com...
> Why do you want a balanced power? Do you have a specific noise problem?

I have in the past. Seems like a cheap way to provide good clean power.
This way, you eliminate the power source as a variable in the noisy power
equation.

 

[Bear]

Archived from groups: rec.audio.high-end (More info?)

jeffc wrote:

> <imtekms@yahoo.com> wrote in message news:daccq70gc5@news2.newsguy.com...
>
>>Why do you want a balanced power? Do you have a specific noise problem?
>
>
> I have in the past. Seems like a cheap way to provide good clean power.
> This way, you eliminate the power source as a variable in the noisy power
> equation.


I responded to this before, but it seems to have gotten waylaid...

What you want is a transformer. A Step Down transformer with a center
tapped 120v secondary. You can buy such things from transformer
companies like Signal Transformer. BUT ---> you need to know how to and
actually be able to mount and enclose this beast in a safe and secure
way. If you don't know how to do this, or have someone you can hire to
do this, don't.

Otherwise you have to buy one already made, for much more money.

My recommendation is to run a 240v line to an area near your gear, then
insert the 240 --> 120vac transformer. This will give you a very stiff
line. Which is good.

The farther from your AC Mains Breaker Panel your gear is, the greater
the benefit to running 240 to a local area and then stepping it down.

Merely running the 120-0-120 legs to the isotransformer will
automatically provide you with a high degree of "common mode" rejection
off the 240vac line.

(some ISO trannies do not have the CT available to run at "0" - these do
not get the above effect)

I suggest using heavy gauge wire for all of the runs - I like 10ga myself.

You can also use a "Corcom" type filter as a common mode HF noise
rejection filter with or without an isolation transformer.

IF you use an isolation transformer it is a very very good idea to run
absolutely everything that is in your system or that is going to be
plugged into your system from the same power source. Not the wall and
also the iso transformer. Keeping the ground & neutral potentials
together is a good idea.

The idea of using a centertap'd secondary from an iso transformer has
limited merti, imho. That's because the iso transformer is already a big
inductor, and already a big LP filter. The benefit from nominally taking
AC from a secondary that looks like 60 - 0 - 60 to the input of your
gear won't really buy you too much since the input transformer
essentially ignores the "0" since it has only two wires.

There might be some benefit if some caps were added to remove "hash" and
"trash" from the line, shunting it to the "0"... but again the iso
tranny already does this on its own, and adding a Corcom unit (or
similar brand) will hit the nail on the head very hard.

All Electronics is selling some 1000va Stancor units now, that seem
pretty hefty and do the 240 - 110 trick but at least the one I have seen
does not have the CT on the 240vac side - you might ask them if any do.

Much depends on what sort of power issues you might be having.

The "balanced power" idea is not useful in many situations at all - it's
better imho to identify the problems and address them in specific.

_-_-bear