(xy) wrote in message . com...

1)can anyone convince me *not* to buy one of these power boxes?


Bill Whitlock of Jensen Transformers points out that symmetrical AC
power only works if your audio equipment has precisely matched
capacitances from each leg of the power line to chassis...which
apparently very little real-world equipment does.

Buster Mudd wrote:
(xy) wrote in message . com...

1)can anyone convince me *not* to buy one of these power boxes?

Bill Whitlock of Jensen Transformers points out that symmetrical AC
power only works if your audio equipment has precisely matched
capacitances from each leg of the power line to chassis...which
apparently very little real-world equipment does.

Even if it doesn't, it still at least halves the noise due to leakage
just because the voltage from each rail to ground is halved. So worst
case if all the leakage is on one leg of the power line, you get a 6 dB
improvement. If the leakage due to capacitance is equal on both sides
of the line, you get a complete elimination of it.

In the real world, the difference is closer to the 6 dB improvement than
the total elimination, but that can be a big deal on an old guitar amp
with leaky line bypass caps, even if it doesn't make any difference whatever
on a console with a well-designed power supply.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.

i don't have any "problems" in my gear, per se. i use excellent
equipment, and the one spec i obsess on is s/n ratio. but it's more
of a sonic-hygeine thing. if simply plugging into a box like the
furman it-1210(?) can make my studio go from 88db to 94db real world
s/n ratio, that's freakin' phenomenal.

i'm honestly not smart enough yet with electronics to do all of these
things like messing with my outlets and stuff. but i did just come up
with a simple equation:
low-noise-freak + lame electronics skills= buy the balanced power
outlet box

thanks for all the insights. so if you see someone obsessing over
these things at aes wearing an atari t-shirt, it's probably me.

Even if it doesn't, it still at least halves the noise due to leakage
just because the voltage from each rail to ground is halved. So worst
case if all the leakage is on one leg of the power line, you get a 6 dB
improvement. If the leakage due to capacitance is equal on both sides
of the line, you get a complete elimination of it.

In the real world, the difference is closer to the 6 dB improvement than
the total elimination, but that can be a big deal on an old guitar amp
with leaky line bypass caps, even if it doesn't make any difference whatever
on a console with a well-designed power supply.
--scott

In article ,
xy wrote:
to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.

One thing I never hear about is the potential problem caused by the
radiated hum field from the huge power transformer you just added to
your control room. I could see such a situation _adding_ hum to a
room just as easily. Are their transformers that well shielded that
this doesn't happen? Somehow, I find that hard to believe...

I guess people expect an improvement because they're spending money
and exerting effort, but it just doesn't seem to be guaranteed
IMHO... and if you put one of these thigns in the wrong rack, I could
imagine that it'd create problems just as easily.

When you come down to it, I don't see what's wrong with opening up
ancient, poorly designed gear and just fixing it. There's a
transformer in just about every power supply and if you drive it
right, there'd be no need to have another transformer upstream.


Regards,

Monte McGuire

On Wed, 10 Sep 2003 05:43:43 +0000 (UTC), (Monte
P McGuire) wrote:

One thing I never hear about is the potential problem caused by the
radiated hum field from the huge power transformer you just added to
your control room. I could see such a situation _adding_ hum to a
room just as easily. Are their transformers that well shielded that
this doesn't happen? Somehow, I find that hard to believe...

It's also a potential problem with variacs for light dimming.
Just something else to keep in mind.

Chris Hornbeck

"xy" wrote in message
om...

to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.

i don't have any "problems" in my gear, per se. i use excellent
equipment, and the one spec i obsess on is s/n ratio. but it's more
of a sonic-hygeine thing. if simply plugging into a box like the
furman it-1210(?) can make my studio go from 88db to 94db real world
s/n ratio, that's freakin' phenomenal.

But that's not how it works.

What has been (correctly) said is that with balanced power, a single noise
source (of many) that may or may not be relevant to certain poorly-designed
equipment drops by 6 dB.

Substantial improvements in component or system performance due to balanced
power are an indictment of the original system. However, in the real world
expediency can have considerable value.

The actual improvement in system performance due to balanced power can still
be vanishing, or lots. YMMV.

xy wrote:

to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.


I regularly run guitar tracks with a noise floor of higher than -40,
and it gets completely masked by other stuff in mixes, not to mention
the guitar signal itself. The noise is muted when that's all's on that
track.

i don't have any "problems" in my gear, per se. i use excellent
equipment, and the one spec i obsess on is s/n ratio. but it's more
of a sonic-hygeine thing. if simply plugging into a box like the
furman it-1210(?) can make my studio go from 88db to 94db real world
s/n ratio, that's freakin' phenomenal.

i'm honestly not smart enough yet with electronics to do all of these
things like messing with my outlets and stuff. but i did just come up
with a simple equation:
low-noise-freak + lame electronics skills= buy the balanced power
outlet box

thanks for all the insights. so if you see someone obsessing over
these things at aes wearing an atari t-shirt, it's probably me.

Even if it doesn't, it still at least halves the noise due to leakage
just because the voltage from each rail to ground is halved. So worst
case if all the leakage is on one leg of the power line, you get a 6 dB
improvement. If the leakage due to capacitance is equal on both sides
of the line, you get a complete elimination of it.

In the real world, the difference is closer to the 6 dB improvement than
the total elimination, but that can be a big deal on an old guitar amp
with leaky line bypass caps, even if it doesn't make any difference whatever
on a console with a well-designed power supply.
--scott


--
Les Cargill

xy wrote:
to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.

Well, the places where these things make a big difference is on things
like old poorly-maintained guitar amps, where 6 dB may not be anywhere
near enough to deal with the hum.

i don't have any "problems" in my gear, per se. i use excellent
equipment, and the one spec i obsess on is s/n ratio. but it's more
of a sonic-hygeine thing. if simply plugging into a box like the
furman it-1210(?) can make my studio go from 88db to 94db real world
s/n ratio, that's freakin' phenomenal.

No, it won't change your S/N ratio whatsoever, because most of the noise
in your gear is thermal noise from the electronics that balanced power
will do nothing to eliminate. All balanced power does is reduce hum due
to chassis leakage. Nothing else. It does nothing about hiss, nothing
about other hum sources.

i'm honestly not smart enough yet with electronics to do all of these
things like messing with my outlets and stuff. but i did just come up
with a simple equation:
low-noise-freak + lame electronics skills= buy the balanced power
outlet box

Try it and see. I think it's generally a waste of money unless you have
gear with power supply problems, but there's enough gear out there with
power supply problems that it can occasionally come in handy.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Monte P McGuire wrote:
In article ,
xy wrote:
to me, 6db is a *gigantic* improvement! doesn't perceived sound drop
in half every 6db? that's huge! i'm kind of surprised that several
people "casually" mentioned a 6db improvement, as if it's a take it or
leave it kind of thing.

One thing I never hear about is the potential problem caused by the
radiated hum field from the huge power transformer you just added to
your control room. I could see such a situation _adding_ hum to a
room just as easily. Are their transformers that well shielded that
this doesn't happen? Somehow, I find that hard to believe...

Nope, that's why we keep the transformer in the power closet fifty
feet away.

When you come down to it, I don't see what's wrong with opening up
ancient, poorly designed gear and just fixing it. There's a
transformer in just about every power supply and if you drive it
right, there'd be no need to have another transformer upstream.

That is the REAL solution to these problems. The reason I have balanced
power is because I can't do this to customer-provided gear, especially in
a live situation where the act is on in ten minutes.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Monte P McGuire wrote:

One thing I never hear about is the potential problem caused by the
radiated hum field from the huge power transformer you just added to
your control room. I could see such a situation _adding_ hum to a
room just as easily. Are their transformers that well shielded that
this doesn't happen? Somehow, I find that hard to believe...

The transformer belongs down the hall in the electrical room, where the
inverse square law can work its magic. Some transformers do spew a lot
more magnetic field than others, and proper orientation also helps.

I can't count the number of facilities I've worked in or on where the
electrical room (often with a megawatt or more of load) is on the other
side of the wall from a room with sensitive telephone, computer, or AV
infrastructure. Sometimes rotating a rack 90º or moving it a few inches
is enough, but other times it takes extraordinary efforts. I even moved
a transformer outside once (it needed an upsize anyway and we just had
to pay the difference between the indoor and outdoor enclosures plus
provide all the ductwork for the utility.)

so if i'm using nothing but neumann mics and focusrite red range and
things like that, i won't hear any benefit from one of these boxes?

xy wrote:
so if i'm using nothing but neumann mics and focusrite red range and
things like that, i won't hear any benefit from one of these boxes?

If you're using an old U47 with a leaky power supply, you might hear a lot
of benefit.

If you're using gear with modern well-designed power supplies, you should not
hear any.

Try it and see.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

ok, good looks like i'm in the clear

Mr. Dorsey's comment about a balanced power supply not helping
"thermal noise" was great. That's probably what i'd be (erroneously)
trying to use it for...to get every type of potential hiss to some
sort of black-hole non-existence. In this case the balanced power box
won't help it seems.

I guess balanced power really centers on 60 cycle "hum" kinds of
things and crusty old tube guitar amps and stratocasters
etc...magnetic field hum stuff. I'd be trying to chase "hiss" with
the thing.

xy wrote:

I guess balanced power really centers on 60 cycle "hum" kinds of
things and crusty old tube guitar amps and stratocasters
etc...magnetic field hum stuff. I'd be trying to chase "hiss" with
the thing.

It fixes one specific hum source: chassis leakage. It doesn't do anything
about induced hums and ground loop problems, really.

But it really does help with that specific hum source.

Also, because it's a transformer, it also cleans up high frequency trash
on the power line, which can result in buzzes and radio interference
problems.

But it's a very specific cure for a very specific problem.
The bottom line, though, is that you should try it and see what it
does. Any of the power filter companies will be willing to loan you
a balanced power transformer on a credit card so you can hear what it
does for you.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."