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alternative to a transformer splitter snake?

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June 8, 2005 2:17:00 PM

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

I need to split 32 channels from the stage to the PA console and to the
recording mixer sitting in the other building 200 ft away.

Here are the alternatives:

Build a transformer splitter, plus the the snake, at a cost of approx
$5,500. Then figure out how to route 150 pounds of copper.

Buy 4x 8ch mic preamps with optical toslink out. Route analog outs to
the PA stage box and optical outs to the AudioRail (or equivalent) ADAT
to ethernet cable converter. Do the same thing in reverse on the other
side, minus the D/A converters (mixer has built-in ADAT cards)

This can be done for about the same cost, over a single ethernet cable
weighting about 5 pounds.

Anyone familiar with the concept? Or maybe done this and willing to
share an opinion?


Thanks,



j.
June 8, 2005 2:17:01 PM

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

On Wed, 08 Jun 2005 10:17:00 GMT, justin <someone@example.net> wrote:

>I need to split 32 channels from the stage to the PA console and to the
>recording mixer sitting in the other building 200 ft away.
>
>Here are the alternatives:
>
>Build a transformer splitter, plus the the snake, at a cost of approx
>$5,500. Then figure out how to route 150 pounds of copper.

Or 4 of these:

http://www.procosound.com/downloads/ms42a.pdf


>
>Buy 4x 8ch mic preamps with optical toslink out. Route analog outs to
>the PA stage box and optical outs to the AudioRail (or equivalent) ADAT
>to ethernet cable converter. Do the same thing in reverse on the other
>side, minus the D/A converters (mixer has built-in ADAT cards)

Do you have any online information abou the audiorails? I'd like to
see it.

Julian
Anonymous
June 8, 2005 2:17:01 PM

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

In article <080620050317019735%someone@example.net>, justin <justin> wrote:
>I need to split 32 channels from the stage to the PA console and to the
>recording mixer sitting in the other building 200 ft away.
>
>Here are the alternatives:
>
>Build a transformer splitter, plus the the snake, at a cost of approx
>$5,500. Then figure out how to route 150 pounds of copper.
>
>Buy 4x 8ch mic preamps with optical toslink out. Route analog outs to
>the PA stage box and optical outs to the AudioRail (or equivalent) ADAT
>to ethernet cable converter. Do the same thing in reverse on the other
>side, minus the D/A converters (mixer has built-in ADAT cards)
>
>This can be done for about the same cost, over a single ethernet cable
>weighting about 5 pounds.
>
>Anyone familiar with the concept? Or maybe done this and willing to
>share an opinion?

I think even if you do all this stuff, you _still_ really need an
isolated split between the PA console and the recoring preamps.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Anonymous
June 8, 2005 2:17:02 PM

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

Julian wrote:
> On Wed, 08 Jun 2005 10:17:00 GMT, justin
<someone@example.net> wrote:
>
>> I need to split 32 channels from the stage to the PA
console and to
>> the recording mixer sitting in the other building 200 ft
away.
>>
>> Here are the alternatives:
>>
>> Build a transformer splitter, plus the the snake, at a
cost of approx
>> $5,500. Then figure out how to route 150 pounds of
copper.
>
> Or 4 of these:
>
> http://www.procosound.com/downloads/ms42a.pdf
>
>
>>
>> Buy 4x 8ch mic preamps with optical toslink out. Route
analog outs to
>> the PA stage box and optical outs to the AudioRail (or
equivalent)
>> ADAT to ethernet cable converter. Do the same thing in
reverse on
>> the other side, minus the D/A converters (mixer has
built-in ADAT
>> cards)
>
> Do you have any online information abou the audiorails?
I'd like to
> see it.

Audiorails have been discussed here a few times, with a
generally favorable outcome. Check google.
June 8, 2005 2:17:02 PM

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

On 8 Jun 2005 08:40:49 -0400, kludge@panix.com (Scott Dorsey) wrote:

>I think even if you do all this stuff, you _still_ really need an
>isolated split between the PA console and the recoring preamps.
>--scott

Why? Doesn't the light give you that isolation.

Julian
June 8, 2005 2:17:03 PM

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

On Wed, 8 Jun 2005 07:36:16 -0400, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>Audiorails have been discussed here a few times, with a
>generally favorable outcome. Check google.

Just thought you might have a bookmark handy :-)

Julian
Anonymous
June 8, 2005 2:17:03 PM

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

In article <r7rda1ldcf8i9gp9dojvo0u42vjngnl756@4ax.com>,
Julian <JulianPAdamsNo@SpamHotmail.Com> wrote:
>On 8 Jun 2005 08:40:49 -0400, kludge@panix.com (Scott Dorsey) wrote:
>
>>I think even if you do all this stuff, you _still_ really need an
>>isolated split between the PA console and the recoring preamps.
>
>Why? Doesn't the light give you that isolation.

That gives you isolation from the truck to the preamp rack, but not
from the preamp rack to the console.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
June 8, 2005 5:11:14 PM

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

Julian wrote:
>
> On Wed, 8 Jun 2005 07:36:16 -0400, "Arny Krueger" <arnyk@hotpop.com>
> wrote:
>
> >Audiorails have been discussed here a few times, with a
> >generally favorable outcome. Check google.
>
> Just thought you might have a bookmark handy


http://audiorail.home.comcast.net/
Anonymous
June 8, 2005 5:18:14 PM

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

You might also see:

http://www.lightviper.com

for the "LightViper".


Julian wrote:
>
> On Wed, 8 Jun 2005 07:36:16 -0400, "Arny Krueger" <arnyk@hotpop.com>
> wrote:
>
> >Audiorails have been discussed here a few times, with a
> >generally favorable outcome. Check google.
>
> Just thought you might have a bookmark handy :-)
>
> Julian
Anonymous
June 8, 2005 10:12:13 PM

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

"justin" <someone@example.net> wrote in message
news:080620050317019735%someone@example.net...
>I need to split 32 channels from the stage to the PA console and to the
> recording mixer sitting in the other building 200 ft away.
>
> Here are the alternatives:
>
> Build a transformer splitter, plus the the snake, at a cost of approx
> $5,500. Then figure out how to route 150 pounds of copper.
>
> Buy 4x 8ch mic preamps with optical toslink out. Route analog outs to
> the PA stage box and optical outs to the AudioRail (or equivalent) ADAT
> to ethernet cable converter. Do the same thing in reverse on the other
> side, minus the D/A converters (mixer has built-in ADAT cards)
>
> This can be done for about the same cost, over a single ethernet cable
> weighting about 5 pounds.
>
> Anyone familiar with the concept? Or maybe done this and willing to
> share an opinion?
>
>
> Thanks,
>
>
>
> j.

There has been discussion of this over at alt.audio.pro.live-sound. You may
want to check the archives.

Mikey
Nova Music Productions
June 9, 2005 1:37:19 AM

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

In article <d86ttl$k95$1@panix2.panix.com>, Scott Dorsey
<kludge@panix.com> wrote:


>
> That gives you isolation from the truck to the preamp rack, but not
> from the preamp rack to the console.
> --scott


That was precisely why I posted the question Scott, the alternative to
a _transformer_ splitter.

I've been thinking about this from another angle: fact is, you don't
need isolation to drive power amps from a PA console balanced out,
although they are both grounded at different ends.

Would this logic apply to the stage preamps feeding the mixer as well?



j.
Anonymous
June 9, 2005 1:37:20 AM

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

>In article <d86ttl$k95$1@panix2.panix.com>, Scott Dorsey
><kludge@panix.com> wrote:
>>
>> That gives you isolation from the truck to the preamp rack, but not
>> from the preamp rack to the console.
>
>That was precisely why I posted the question Scott, the alternative to
>a _transformer_ splitter.
>
>I've been thinking about this from another angle: fact is, you don't
>need isolation to drive power amps from a PA console balanced out,
>although they are both grounded at different ends.

Sometimes you do. Sometimes under bad conditions, transformers can be
your salvation in that circumstance. Sometimes you don't need
transformers but you _do_ need to lift the signal grounds at the console.

With mike-level signals, you get the same problems, just 40 dB worse.
It might be fine and then again it might not be, and it might be fine in
one city but when you move to another you have RF issues.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
June 9, 2005 6:06:06 AM

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

In article <d87q1d$d2u$1@panix2.panix.com>, Scott Dorsey
<kludge@panix.com> wrote:

> >In article <d86ttl$k95$1@panix2.panix.com>, Scott Dorsey
> ><kludge@panix.com> wrote:
> >>
> >> That gives you isolation from the truck to the preamp rack, but not
> >> from the preamp rack to the console.
> >
> >That was precisely why I posted the question Scott, the alternative to
> >a _transformer_ splitter.
> >
> >I've been thinking about this from another angle: fact is, you don't
> >need isolation to drive power amps from a PA console balanced out,
> >although they are both grounded at different ends.
>
> Sometimes you do. Sometimes under bad conditions, transformers can be
> your salvation in that circumstance.


Agreed, in fact it is the only way to do this and guarantee no problem
operation. As always, it is the budget that gets in the way.


> transformers but you _do_ need to lift the signal grounds at the console.

What would be better, switch cable shields from pins 1 each end to the
XLR chasis, or just disconnect pin 1 at one end?

Maybe powering preamp rack with isolating 120/120v transformer so each
mic pre gets grounded through the PA snake?

>
> With mike-level signals, you get the same problems, just 40 dB worse.
> It might be fine and then again it might not be, and it might be fine in
> one city but when you move to another you have RF issues.

It is a fixed installation, but I see your point. I remember when
broadcast consoles used to have 600 ohms transformer isolated
inputs/outputs on _each_ module.


j.
Anonymous
June 9, 2005 6:06:07 AM

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

"justin" <someone@example.net> wrote in message
news:080620051906044278%someone@example.net...
> In article <d87q1d$d2u$1@panix2.panix.com>, Scott Dorsey
> <kludge@panix.com> wrote:
>
> > >In article <d86ttl$k95$1@panix2.panix.com>, Scott Dorsey
> > ><kludge@panix.com> wrote:
> > >>
> > >> That gives you isolation from the truck to the preamp rack, but not
> > >> from the preamp rack to the console.
> > >
> > >That was precisely why I posted the question Scott, the alternative to
> > >a _transformer_ splitter.
> > >
> > >I've been thinking about this from another angle: fact is, you don't
> > >need isolation to drive power amps from a PA console balanced out,
> > >although they are both grounded at different ends.
> >
> > Sometimes you do. Sometimes under bad conditions, transformers can be
> > your salvation in that circumstance.
>
>
> Agreed, in fact it is the only way to do this and guarantee no problem
> operation. As always, it is the budget that gets in the way.
>
>
> > transformers but you _do_ need to lift the signal grounds at the
console.
>
> What would be better, switch cable shields from pins 1 each end to the
> XLR chasis, or just disconnect pin 1 at one end?
>
> Maybe powering preamp rack with isolating 120/120v transformer so each
> mic pre gets grounded through the PA snake?
>
> >
> > With mike-level signals, you get the same problems, just 40 dB worse.
> > It might be fine and then again it might not be, and it might be fine in
> > one city but when you move to another you have RF issues.
>
> It is a fixed installation, but I see your point. I remember when
> broadcast consoles used to have 600 ohms transformer isolated
> inputs/outputs on _each_ module.
>
Rent a resistive splitter from your local sound company. Many (most?) don't
use transformers...should be easy to find. Try it. If it works, go that
way.

Otherwise, it's 200 #'s of copper....

jak

>
> j.
Anonymous
June 9, 2005 6:20:56 AM

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

On Thu, 09 Jun 2005 02:06:06 GMT, justin <someone@example.net> wrote:

>What would be better, switch cable shields from pins 1 each end to the
>XLR chasis, or just disconnect pin 1 at one end?

Now *this* is an interesting question.

>Maybe powering preamp rack with isolating 120/120v transformer so each
>mic pre gets grounded through the PA snake?

Not sure if I'm reading you correctly, but at first blush
you're describing a safety issue. 'Course I'm very likely
just misreading as usual.

Chris Hornbeck
"For a change, she got out,
'Fore he hurt her bad.
Took her records and clothes,
And pictures of her boy." -Elliott Smith
Anonymous
June 9, 2005 9:29:08 AM

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

"justin" <someone@example.net> wrote in message
news:080620050317019735%someone@example.net...
> I need to split 32 channels from the stage to the PA
console and to the
> recording mixer sitting in the other building 200 ft away.
>
> Here are the alternatives:
>
> Build a transformer splitter, plus the the snake, at a
cost of approx
> $5,500. Then figure out how to route 150 pounds of copper.
>
> Buy 4x 8ch mic preamps with optical toslink out. Route
analog outs to
> the PA stage box and optical outs to the AudioRail (or
equivalent) ADAT
> to ethernet cable converter. Do the same thing in reverse
on the other
> side, minus the D/A converters (mixer has built-in ADAT
cards)
>
> This can be done for about the same cost, over a single
ethernet cable
> weighting about 5 pounds.

> Anyone familiar with the concept? Or maybe done this and
willing to
> share an opinion?

Given that the issues of isolation and grounding at both
mixers has been raised, why not drive both mixers optically?

http://www.american-digital.com/PRODUCTS/Calrad_35-442_...
Anonymous
June 9, 2005 1:22:14 PM

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

In article <080620051906044278%someone@example.net>, justin <justin> wrote:
>
>> transformers but you _do_ need to lift the signal grounds at the console.
>
>What would be better, switch cable shields from pins 1 each end to the
>XLR chasis, or just disconnect pin 1 at one end?

Just disconnect at one end. Always keep around a bag of barrel connectors
with pin 1 broken for just that application.

>Maybe powering preamp rack with isolating 120/120v transformer so each
>mic pre gets grounded through the PA snake?

That certainly wouldn't hurt.

>> With mike-level signals, you get the same problems, just 40 dB worse.
>> It might be fine and then again it might not be, and it might be fine in
>> one city but when you move to another you have RF issues.
>
>It is a fixed installation, but I see your point. I remember when
>broadcast consoles used to have 600 ohms transformer isolated
>inputs/outputs on _each_ module.

A lot of higher grade PA consoles still come close. Look inside a
Yamaha PM-2000 some time. Not one on every channel strip, but just
about every input and output is isolated.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
June 9, 2005 1:59:37 PM

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

In article <080620051906044278%someone@example.net> justin writes:

> > transformers but you _do_ need to lift the signal grounds at the console.
>
> What would be better, switch cable shields from pins 1 each end to the
> XLR chasis, or just disconnect pin 1 at one end?

I don't totally agree with the need to lift the cable shield when
using a transformer splitte, but in realilty it often works out better
to do so. It depends on the console, and most consoles have The Pin 1
Problem. In theory (and it works just fine in practice if you do it
right on both ends) Pin 1 should go directly to the audio ground
point, and that audio ground point should go directly to the metal
case. This way, the shield doesn't carry any audio current (because
it's grounded at both ends) and it acts as a continuation of the
chassis to shield the equipment from external interference.

But what happens in real life is that resistance gets in the way, and
"ground" on both ends of the cable (since they're connected to
different devices) aren't exactly at the same potential and same
impedance to real ground, so there's a way for audio current to flow
through the shield. When it gets to Pin 1 of the receiving device,
because it doesn't go directly to ground (and does not collect $200)
that signal current is sitting there waiting to be amplified like
everything else going into the console.


--
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
Anonymous
June 9, 2005 6:45:57 PM

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

On 6/8/05 6:04 PM, in article d87q1d$d2u$1@panix2.panix.com, "Scott Dorsey"
<kludge@panix.com> wrote:

>> In article <d86ttl$k95$1@panix2.panix.com>, Scott Dorsey
>> <kludge@panix.com> wrote:
>>>
>>> That gives you isolation from the truck to the preamp rack, but not
>>> from the preamp rack to the console.
>>
>> That was precisely why I posted the question Scott, the alternative to
>> a _transformer_ splitter.
>>
>> I've been thinking about this from another angle: fact is, you don't
>> need isolation to drive power amps from a PA console balanced out,
>> although they are both grounded at different ends.
>
> Sometimes you do. Sometimes under bad conditions, transformers can be
> your salvation in that circumstance. Sometimes you don't need
> transformers but you _do_ need to lift the signal grounds at the console.
>
> With mike-level signals, you get the same problems, just 40 dB worse.
> It might be fine and then again it might not be, and it might be fine in
> one city but when you move to another you have RF issues.
> --scott

Hands Raised In Warning And Agreement

-YOU- don't want noise on your signal... BUT MORESO:
You do NOT want to introduce same into the house system!
Spending 15min trying to track down a buzsomething that the house tech
INSISTS was never there before you walked in makes for late shows, annoyed
crew, confused artists and hell in your head you don;t want.
Do This Right. Spend the Money.
June 10, 2005 12:49:11 AM

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

In article <4i9fa1d6m84g6ciqikgrjtk37rr6ni4oed@4ax.com>, Chris Hornbeck
<chrishornbeckremovethis@att.net> wrote:

> On Thu, 09 Jun 2005 02:06:06 GMT, justin <someone@example.net> wrote:
>
> >What would be better, switch cable shields from pins 1 each end to the
> >XLR chasis, or just disconnect pin 1 at one end?
>
> Now *this* is an interesting question.

As much as the discussion I once had about "is there a diference in
wiring between a mic cable and a line cable?"


>
> >Maybe powering preamp rack with isolating 120/120v transformer so each
> >mic pre gets grounded through the PA snake?
>
> Not sure if I'm reading you correctly, but at first blush
> you're describing a safety issue. 'Course I'm very likely
> just misreading as usual.

Well, a mic preamp is, by default, always connected to some device, a
mixer, which is, by default, grounded.

Microphone chassis (body) is normally wired to pin 1, to cable shield,
to console ground. If we put a microphone preamp in the path, it will
pass the ground through the pins 1, input to output.

Which would leave the chassis of the preamp floating, but AFAIK, the
few ones I have at hand have pins 1 connected to chassis - just beeped
with the tester.

So, I believe it doesn't change much in terms of safety.

Does this make sense?

j.





>
> Chris Hornbeck
> "For a change, she got out,
> 'Fore he hurt her bad.
> Took her records and clothes,
> And pictures of her boy." -Elliott Smith
Anonymous
June 10, 2005 1:49:09 AM

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

On Thu, 09 Jun 2005 20:49:11 GMT, justin <someone@example.net> wrote:

>Well, a mic preamp is, by default, always connected to some device, a
>mixer, which is, by default, grounded.

Yeah, and as long as they're close, no problem. I've gotten
the idea of mic preamps in the pit in my head, and sometimes
can't shake it.

Thanks,

Chris Hornbeck
June 10, 2005 1:56:53 AM

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

In article <BECDCE63.9D90%ten@nozirev.gamnocssj.com>, SSJVCmag
<ten@nozirev.gamnocssj.com> wrote:


> Hands Raised In Warning And Agreement
>
> -YOU- don't want noise on your signal... BUT MORESO:
> You do NOT want to introduce same into the house system!
> Spending 15min trying to track down a buzsomething that the house tech
> INSISTS was never there before you walked in makes for late shows, annoyed
> crew, confused artists and hell in your head you don;t want.

Been there, know the drill. But this is a fixed installation system,
not a mobile.

> Do This Right. Spend the Money.
>
>

Yes. But what is Right? -THEY- want to know as they are paying for it.

If you were ever in a similar position you'd know that, regrettably,
the Politics of Spending has the higher power than persuasion of Doing
It _absolutely_ Right.


j.
June 10, 2005 2:08:29 AM

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

In article <t46dnRf1I5Z5ljXfRVn-qg@comcast.com>, Arny Krueger
<arnyk@hotpop.com> wrote:


>
> Given that the issues of isolation and grounding at both
> mixers has been raised, why not drive both mixers optically?
>

Because _digital_ PA consoles are as rare as the PA "engineers" who
know how to use them?

;-)

Great idea, though. Thanks. I was wandering if and how I could split a
toslink. One more idea to play with.

j.
Anonymous
June 10, 2005 2:08:30 AM

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

justin wrote:
> In article <t46dnRf1I5Z5ljXfRVn-qg@comcast.com>, Arny
Krueger
> <arnyk@hotpop.com> wrote:

>> Given that the issues of isolation and grounding at both
>> mixers has been raised, why not drive both mixers
optically?

> Because _digital_ PA consoles are as rare as the PA
"engineers" who
> know how to use them?

Actually, if you lurk over in alt.audio.pro.live.sound,
you'll find quite a few digital console advocates. I'm still
learning how to spell 02R96, but so far it has been
productive and fun.

> Great idea, though. Thanks. I was wandering if and how I
could split a
> toslink. One more idea to play with.

Frankly, it seems quite obvious. ;-)
Anonymous
June 10, 2005 7:51:43 AM

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

On 6/9/05 5:56 PM, in article 090620051456534178%someone@example.net,
"justin" <someone@example.net> wrote:

> In article <BECDCE63.9D90%ten@nozirev.gamnocssj.com>, SSJVCmag
> <ten@nozirev.gamnocssj.com> wrote:
>
>
>> Hands Raised In Warning And Agreement
>>
>> -YOU- don't want noise on your signal... BUT MORESO:
>> You do NOT want to introduce same into the house system!
>> Spending 15min trying to track down a buzsomething that the house tech
>> INSISTS was never there before you walked in makes for late shows, annoyed
>> crew, confused artists and hell in your head you don;t want.
>
> Been there, know the drill. But this is a fixed installation system,
> not a mobile.

OK.. I got confoosed somewhere along here, I thought this was a touring
group and the mobile-recording-rig would be getting patched into whatever
house system happened at each venue stop... Do I need to change the meds
(again)?


>
>> Do This Right. Spend the Money.
>>
>>
>
> Yes. But what is Right? -THEY- want to know as they are paying for it.
>
> If you were ever in a similar position you'd know that, regrettably,
> the Politics of Spending has the higher power than persuasion of Doing
> It _absolutely_ Right.

Just trying to reenforce the bigger overiding 'after you let the spending
drive the train and the train has Issues, who gets the blame'.
Squeaky-wheel now beats damnable buzzy tracks later.
!