Dimmers

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

Every sound system manual I have ever seen recommends strongly you have
dimmers on a separate phase from the sound system.

The problem with this is, most dimmer packs are three phase.

Short of not using 1/3 of your channels, what can be done about the noise
problems?

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

Patrick Dunford wrote:

> Every sound system manual I have ever seen recommends strongly you have
> dimmers on a separate phase from the sound system.
>
> The problem with this is, most dimmer packs are three phase.
>
> Short of not using 1/3 of your channels, what can be done about the noise
> problems?

Most of those sound system manuals are misusing the word phase.
What they were trying to stop with that advice is ground loops that
allow the hash and trash generated by dimmers to enter the signal
paths.
The sound system should be on a separate power panel than
the dimmers, and they both should have large friendly ground
conductors connected to a good building grounding system.

--Dale

 

[george]

Archived from groups: nz.tech,rec.audio.pro (More info?)

In article <MPG.1bbf5e70af9d390c98a4e9@news.paradise.net.nz>,
Patrick Dunford <patrickdunford@nomail.invalid> wrote:

> Every sound system manual I have ever seen recommends strongly you have
> dimmers on a separate phase from the sound system.
>
> The problem with this is, most dimmer packs are three phase.
>
> Short of not using 1/3 of your channels, what can be done about the noise
> problems?

three hots into the dimmer
and you only have two legs coming from the distro
if it is one dimmer opwer it all off one leg
if it is multi dimmers power I half off one leg and the other half off
the other
just use a service and cableing adaquate for the job

most venues that use lots of portable systems have seperate services for
sound and lights with independent disconnects

I just bought the behringer dimmer that was set up for 3 phase
20 amp120v/ph
I hard wired it to three single breakers in a disconnect(breaker box)
all on the same phase this disconnect connects with tails and camlocs
to a mains(at venue) that can supply at least 60 amps/phase
if I can not get the power I have two option
1 down size lighting rig
2 limit the draw by restricting the maximum brightness of the
lamps(easily done with a trimmer on my control desk)
george

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

George wrote:

<Snip>

> most venues that use lots of portable systems have seperate services for
> sound and lights with independent disconnects
>
> I just bought the behringer dimmer that was set up for 3 phase
> 20 amp120v/ph
> I hard wired it to three single breakers in a disconnect(breaker box)
> all on the same phase this disconnect connects with tails and camlocs
> to a mains(at venue) that can supply at least 60 amps/phase

Is the neutral from the dimmer rated for 60A? If running single phase it
will need to be.

The other thing to watch is that RMS/AVERAGE thing when reducing power draw
by turning down at the desk. Ohh and this applies to three phase loads as
well as it is quite possible for the neutral current to exceed any given
phase current due to third harmonic summing in the neutral.

Just a heads up about some of the details that may not be obvious to people
considering doing this.

Regards, Dan (who is profoundly glad that he is in a 230/400V country).
--
** The email address *IS* valid, do NOT remove the spamblock
And on the evening of the first day the lord said...........
..... LX 1, GO!; and there was light.

 

[george]

Archived from groups: nz.tech,rec.audio.pro (More info?)

In article <cj2gef$kg8$1$8302bc10@news.demon.co.uk>,
Dan Mills <dmills@spamblock.demon.co.uk> wrote:

> George wrote:
>
> <Snip>
>
> > most venues that use lots of portable systems have seperate services for
> > sound and lights with independent disconnects
> >
> > I just bought the behringer dimmer that was set up for 3 phase
> > 20 amp120v/ph
> > I hard wired it to three single breakers in a disconnect(breaker box)
> > all on the same phase this disconnect connects with tails and camlocs
> > to a mains(at venue) that can supply at least 60 amps/phase
>
> Is the neutral from the dimmer rated for 60A? If running single phase it
> will need to be.

yes 4 guage free air conductors and the ground is 2
i also have a real disto that runs 2/0 on the same sized camlocs
>
> The other thing to watch is that RMS/AVERAGE thing when reducing power draw
> by turning down at the desk. Ohh and this applies to three phase loads as
> well as it is quite possible for the neutral current to exceed any given
> phase current due to third harmonic summing in the neutral.

this I was not aware of , thanks
>
> Just a heads up about some of the details that may not be obvious to people
> considering doing this.
>
> Regards, Dan (who is profoundly glad that he is in a 230/400V country).

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

On Sat, 25 Sep 2004 09:53:19 +1200, Patrick Dunford
<patrickdunford@nomail.invalid> wrote:

>Every sound system manual I have ever seen recommends strongly you have
>dimmers on a separate phase from the sound system.

But, since most homes only have one phase , domestic users hook all
their dimmers on different rings or spurs or whatever sparkies call
the individual circuits. As in, a different spur to the stereo.

El P.

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

Patrick Dunford <patrickdunford@nomail.invalid> wrote:
>Every sound system manual I have ever seen recommends strongly you have
>dimmers on a separate phase from the sound system.
>
>The problem with this is, most dimmer packs are three phase.
>
>Short of not using 1/3 of your channels, what can be done about the noise
>problems?

1. Don't use dimmers at all.

2. Get a separate service from the dimmers.

3. Spend the money for expensive dimmer packs that have some degree of noise
filtering, then put them on a three-phase isolation transformer from the
main service.

4. Use an ancient autotransformer board.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

On Sat, 25 Sep 2004 09:53:19 +1200, Patrick Dunford
<patrickdunford@nomail.invalid> wrote:

>Every sound system manual I have ever seen recommends strongly you have
>dimmers on a separate phase from the sound system.
>
>The problem with this is, most dimmer packs are three phase.
>
>Short of not using 1/3 of your channels, what can be done about the noise
>problems?

Lots of batteries? But seriously, how old is the room you'll be
working in? I've found, in our new (1995) theater that I can just
plug randomly into Edison wherever I want and not worry. About
that anyway.

There's nothing you can do about the dimmers, which is scary, but
there may not be any practical problems, which is cool.

RFI trapping at the input to electronics may still prove to be
audible, and is worth experimenting with, if only for peace of
mind. I play with clamp-on ferrite donuts on signal and power.

Good fortune,

Chris Hornbeck

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

"Scott Dorsey"
> Patrick Dunford
> >
> >Every sound system manual I have ever seen recommends strongly you have
> >dimmers on a separate phase from the sound system.
> >
>The problem with this is, most dimmer packs are three phase.
> >
> >Short of not using 1/3 of your channels, what can be done about the noise
> >problems?
>
>
> 1. Don't use dimmers at all.
>

** Dorsey is as clueless as ever.


> 2. Get a separate service from the dimmers.


** Won't help when ground system noise is the issue.

>
> 3. Spend the money for expensive dimmer packs that have some degree of
noise
> filtering, then put them on a three-phase isolation transformer from
the
> main service.
>

** Dorsey has not got a clue.


> 4. Use an ancient autotransformer board.


** That is no damn board - that is a room full of motorised hardware
that went out with Noah's Arc.


The real answer is to make sure your PA system is genuinely earth loop hum
free - then it will be dimmer buzz fee to in all probability too.

However, electric guitars, keyboards, amps and other items of stage gear
are the NUMBER ONE culprits for picking up dimmer buzz - and there is
SFA **you** can do about them.




............. Phil

 

[Richard]

Archived from groups: nz.tech,rec.audio.pro (More info?)

Patrick Dunford wrote:

> Every sound system manual I have ever seen recommends strongly you have
> dimmers on a separate phase from the sound system.
>
> The problem with this is, most dimmer packs are three phase.
>
> Short of not using 1/3 of your channels, what can be done about the noise
> problems?

The issue will be with earth loops, they exagerate the noise pickup from dimmers.

Solve the earth loop, solve the buzz generally.

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

richard <rich@ihug.co.nz> wrote:
>The issue will be with earth loops, they exagerate the noise pickup from dimmers.

>Solve the earth loop, solve the buzz generally.

For the most part this is true, but keeping the trash out of the power line
as much as possible with careful power supply to the dimmers is still a good
idea.

Because you're going to encounter equipment with internal ground loops (yes,
I realize Phil doesn't believe in the Pin 1 problem, but there was a nice
paper at the last AES show on it that is worth looking up), you're going to
be using wireless mikes with poor front-ends that pick up RF trash directly,
and all-in-all, sooner or later you're going to have someone working in the
hall that will be in some situation where noise is an issue. So try and do
it right with the initial install.

Don't forget clearcom systems either....
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

In article <cj5292$9f7$1@panix2.panix.com> in nz.tech on 25 Sep 2004
20:25:06 -0400, Scott Dorsey <kludge@panix.com> says...
> Patrick Dunford <patrickdunford@nomail.invalid> wrote:
> >Every sound system manual I have ever seen recommends strongly you have
> >dimmers on a separate phase from the sound system.
> >
> >The problem with this is, most dimmer packs are three phase.
> >
> >Short of not using 1/3 of your channels, what can be done about the noise
> >problems?
>
> 1. Don't use dimmers at all.
>
> 2. Get a separate service from the dimmers.
>
> 3. Spend the money for expensive dimmer packs that have some degree of noise
> filtering, then put them on a three-phase isolation transformer from the
> main service.

How does running your sound gear on isolation transformers go?

We don't get much noise now, except for using three channels where the
mains cables run too close to the audio lines.

 

[Guest]

Archived from groups: nz.tech,rec.audio.pro (More info?)

Patrick Dunford <patrickdunford@nomail.invalid> wrote:
>
>How does running your sound gear on isolation transformers go?

It allows you to break connection between your grounding system and the
building grounding system. It gives you some degree of low-pass filtering
on the power line.

But, it does nothing about the RF trash that is radiating from the building
power system and from the lighting cables. RF trash that floats through the
air and couples into audio gear, even though it's not coming into the audio
gear through the power line.

>We don't get much noise now, except for using three channels where the
>mains cables run too close to the audio lines.

Well, move them and stop worrying so much. If you don't have noise problems,
don't worry about noise. If you have noise problems, find out what specific
problems they are and fix them.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

>> 3. Spend the money for expensive dimmer packs that have some degree of
>noise
>> filtering, then put them on a three-phase isolation transformer from the
>> main service.
>
>
Back in the mid-late 60's, we built a new studio and had the buzzing and other
artifacts from the studio dimmers. We wound up placing the lighting on
isolation transformers to eliminate the interference with audio. I would hope
things have progressed further by now. Isolation was a little expensive.


--Wayne

-"sounded good to me"-

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

Is it just me or does anyone else noticed how much nicer rap is after having
killfiled the philbot. What a relief to get rid of that nasty, fuzzy logic.


Ty Ford








-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

So you DO have a kill file????

Al

On Sun, 26 Sep 2004 11:13:49 -0400, Ty Ford <tyreeford@comcast.net>
wrote:

>Is it just me or does anyone else noticed how much nicer rap is after having
>killfiled the philbot. What a relief to get rid of that nasty, fuzzy logic.
>
>
>Ty Ford
>
>
>
>
>
>
>
>
>-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
>stuff are at www.tyford.com

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

"Ty Ford" wrote:
> Is it just me or does anyone else noticed how much nicer rap is after
having
> killfiled the philbot. What a relief to get rid of that nasty, fuzzy
logic.

It's better, but since it still appears in other people's quoted replies
it's like there's this weird echo which is even stranger and more insane
than the actual posts.

-jw

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

playon wrote:

> So you DO have a kill file?

Ty got a new newsreader some time ago. (Pay attention, will ya? <g>)
Still, that doesn't mean that having four wheel drive makes driving
around and over piles of excrement a pleasure.

--
ha

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <qHH5d.47592$Ot3.42920@twister.nyc.rr.com> johnwashburn99@nyc.rr.com writes:

> "Ty Ford" wrote:
> > Is it just me or does anyone else noticed how much nicer rap is after
> having
> > killfiled the philbot.

> It's better, but since it still appears in other people's quoted replies

Also, all it takes is posting a message with his name in it and he'll
reply with an insulting remark.

Mark my words.

--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

>> Ty got a new newsreader some time ago. (Pay attention, will ya? <g>)
>> Still, that doesn't mean that having four wheel drive makes driving
>> around and over piles of excrement a pleasure.
>>

However, that is what the steering wheel is for...