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Thomas Bishop
Guest
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 Posted:
Wed Nov 09, 2005 1:08 am Post subject:
Stage Box Idea |
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I have an idea to build some stage boxes at my church and wanted some
input (no pun intended). I would like to take the existing XLR plate,
punch some new holes for 1/4" jacks, wire in a transformer on each, and
have built-in direct boxes. My question is regarding the wiring:
Would it be better to use a switch to select one or the other signal
path or would the wiring (and only using one at a time) do the trick?
If I needed some type of switch, what should I be looking for?
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Scott Dorsey
Guest
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| Posted:
Wed Nov 09, 2005 2:43 am Post subject:
Re: Stage Box Idea |
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In article <1131476933.696723.24730@g14g2000cwa.googlegroups.com>,
Thomas Bishop <bishopthomas@hotmail.com> wrote:
| Quote: | I have an idea to build some stage boxes at my church and wanted some
input (no pun intended). I would like to take the existing XLR plate,
punch some new holes for 1/4" jacks, wire in a transformer on each, and
have built-in direct boxes. My question is regarding the wiring:
Would it be better to use a switch to select one or the other signal
path or would the wiring (and only using one at a time) do the trick?
If I needed some type of switch, what should I be looking for?
|
Use a DPDT switch with gold or silver contacts (whichever is cheaper)
to switch both signal leads. And don't forget a ground lift on the
1/4" in.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis." |
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Jim Gregory
Guest
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| Posted:
Wed Nov 09, 2005 3:04 am Post subject:
Re: Stage Box Idea |
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"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr2kk$bk3$1@panix2.panix.com...
| Quote: | In article <1131476933.696723.24730@g14g2000cwa.googlegroups.com>,
Thomas Bishop <bishopthomas@hotmail.com> wrote:
I have an idea to build some stage boxes at my church and wanted some
input (no pun intended). I would like to take the existing XLR plate,
punch some new holes for 1/4" jacks, wire in a transformer on each, and
have built-in direct boxes. My question is regarding the wiring:
Would it be better to use a switch to select one or the other signal
path or would the wiring (and only using one at a time) do the trick?
If I needed some type of switch, what should I be looking for?
Use a DPDT switch with gold or silver contacts (whichever is cheaper)
to switch both signal leads. And don't forget a ground lift on the
1/4" in.
--scott
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I advise you avoid silver-plated switches at Mic level. Easily tarnished.
Self-wiping gold-plated switches are best for changing over input mode or
Ground/Earth Lift but, do remember, the permanent Grounding of any
mains-operated equipment with exposed metal parts is paramount for safety.
And that bonding goes for the wall-panel -plate- for XLRs, jack conns, etc.
Hum-loop considerations are secondary here. Remember last week's baptismal
electrocution whose amateurish cause is still a mystery. While you are at
it, inspect the integrity of whole electrical installation in the church.
Jim |
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Scott Dorsey
Guest
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| Posted:
Wed Nov 09, 2005 3:29 am Post subject:
Re: Stage Box Idea |
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Jim Gregory <jim.greg@ntlworld.com> wrote:
| Quote: |
I advise you avoid silver-plated switches at Mic level. Easily tarnished.
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Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis." |
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Jim Gregory
Guest
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| Posted:
Wed Nov 09, 2005 3:46 am Post subject:
Re: Stage Box Idea |
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"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr5c7$lfb$1@panix2.panix.com...
| Quote: | Jim Gregory <jim.greg@ntlworld.com> wrote:
I advise you avoid silver-plated switches at Mic level. Easily tarnished.
Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
--scott
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In the '70s we changed all our1/4" PO TRS jackfields from silver- to
palladium-plated contacts to improve line-level reliability with inserted
brass B gauge jackplugs, but I live and learn.
Jim |
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Arny Krueger
Guest
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| Posted:
Wed Nov 09, 2005 4:02 am Post subject:
Re: Stage Box Idea |
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"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr5c7$lfb$1@panix2.panix.com
| Quote: | Jim Gregory <jim.greg@ntlworld.com> wrote:
I advise you avoid silver-plated switches at Mic level.
Easily tarnished.
Right, isn't that the point? The tarnish is highly
conductive and very inert. It looks nasty, but it
doesn't affect the contact quality. --scott
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Also, most reasonable switches have strong self-wiping
action built in. |
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Scott Dorsey
Guest
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| Posted:
Wed Nov 09, 2005 4:36 am Post subject:
Re: Stage Box Idea |
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Jim Gregory <jim.greg@ntlworld.com> wrote:
| Quote: | "Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr5c7$lfb$1@panix2.panix.com...
Jim Gregory <jim.greg@ntlworld.com> wrote:
I advise you avoid silver-plated switches at Mic level. Easily tarnished.
Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
In the '70s we changed all our1/4" PO TRS jackfields from silver- to
palladium-plated contacts to improve line-level reliability with inserted
brass B gauge jackplugs, but I live and learn.
|
Did it help?
I know the unplated brass stuff is a major pain, because the copper oxide
forms a very nasty rectification layer if you don't keep the things clean.
So maybe this was a workaround to deal with plug problems. Did it do any good?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis." |
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Jim Gregory
Guest
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| Posted:
Wed Nov 09, 2005 5:33 am Post subject:
Re: Stage Box Idea |
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"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr98q$ru1$1@panix2.panix.com...
| Quote: | Jim Gregory <jim.greg@ntlworld.com> wrote:
"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr5c7$lfb$1@panix2.panix.com...
Jim Gregory <jim.greg@ntlworld.com> wrote:
I advise you avoid silver-plated switches at Mic level. Easily
tarnished.
Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
In the '70s we changed all our1/4" PO TRS jackfields from silver- to
palladium-plated contacts to improve line-level reliability with inserted
brass B gauge jackplugs, but I live and learn.
Did it help?
I know the unplated brass stuff is a major pain, because the copper oxide
forms a very nasty rectification layer if you don't keep the things clean.
So maybe this was a workaround to deal with plug problems. Did it do any
good?
--scott
--
As far as I know. from mid '70s, palladium-plated became UK broadcast |
industry standard for 1/4" TRS and TT Bantam jackfields. We still cleaned
our patchcords monthly with impregnated wadding.
Must be something better in palladium coatings that is preferable to silver.
Jim
Jim |
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Mark Robinson
Guest
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| Posted:
Wed Nov 09, 2005 5:42 am Post subject:
Re: Stage Box Idea |
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Hi Scott,
You seem to way out in left field on this. I've never used silver contacts
in dry circuit conditions. Tarnish is NOT a good conductor. I suppose if a
switch has some sort of wiping action, you might be able to get away using
silver, but I would not chance it. I've seen many misapplied switches and
relays that have failed in equipment because of this. Here is a link to
NKK's web site with some info. If you read it, you'll see that they do not
recommend silver for dry circuit conditions.
http://www.nkkswitches.com/electrical.asp
Mark
"Scott Dorsey" <kludge@panix.com> wrote in message
news:dkr5c7$lfb$1@panix2.panix.com...
| Quote: | Jim Gregory <jim.greg@ntlworld.com> wrote:
I advise you avoid silver-plated switches at Mic level. Easily tarnished.
Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis." |
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Guest
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| Posted:
Wed Nov 09, 2005 9:40 pm Post subject:
Re: Stage Box Idea |
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Arny Krueger <arnyk@hotpop.com> wrote:
| Quote: | "Jim Gregory" <jim.greg@ntlworld.com> wrote in message
news:Snlcf.11623$Cq4.7691@newsfe7-gui.ntli.net
"Mark Robinson" <mark.rob@verizon.net> wrote in message
news:PRccf.16746$Q27.4310@trnddc02...
I was concerned only about the unreliability of dull
silvered contacts either when joining mic-level ccts
handling up to a few milliVolts (+ any phantoming DC) or
when making ccts carrying a few milliWatts at line level.
For dry circuits - two words: reed relays.
|
I like mercury wetted reed relays myself...
--
Aaron |
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Scott Dorsey
Guest
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| Posted:
Wed Nov 09, 2005 9:56 pm Post subject:
Re: Stage Box Idea |
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Mark Robinson <mark.rob@verizon.net> wrote:
| Quote: |
You seem to way out in left field on this. I've never used silver contacts
in dry circuit conditions. Tarnish is NOT a good conductor. I suppose if a
switch has some sort of wiping action, you might be able to get away using
silver, but I would not chance it. I've seen many misapplied switches and
relays that have failed in equipment because of this. Here is a link to
NKK's web site with some info. If you read it, you'll see that they do not
recommend silver for dry circuit conditions.
http://www.nkkswitches.com/electrical.asp
|
The ITT Radio Engineer's Handbook says that tarnish (silver sulphide)
is higher resistance than silver itself, but still fairly low resistance.
But they don't give any real numbers for it, and I can't find any.
They also say that palladium gives a good compromise between cost and
tarnish resistance, while lasting longer than comparable gold plating.
I should say that when contacts wear out and wear through the plating,
they start having big troubles that seem to be fixed by cleaning but
don't stay fixed for long. It's entirely possible that the previous
poster's problems with silver plated contacts which were fixed with
newer palladium types might actually just have been a case of worn-out
contacts.
The electrical contact guy here told me that the main problem with
silver plate is that it forms little pinholes through the plating,
air gets into the copper underneath and copper salts come streaming
out forming red spots that are called the "red plague." I have never
seen this.
He, though, sent me to this thing:
http://nepp.nasa.gov/whisker/reference/tech_papers/chudnovsky2002-paper-silver-corrosion-whiskers.pdf
which I can't see from here.
So I still don't know the story. Anybody know the actual resistivity
of silver sulphide?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis." |
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anahata
Guest
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| Posted:
Thu Nov 10, 2005 12:41 am Post subject:
Re: Stage Box Idea |
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Scott Dorsey wrote:
[re: silver]
| Quote: |
Right, isn't that the point? The tarnish is highly conductive and very
inert. It looks nasty, but it doesn't affect the contact quality.
|
The point of silver is it has higher conductivity than copper. For that
reason it is used for high current switches.
Low level signals don't work well with silver because of the tarnish :
that what gold plated contacts are for.
(look up some switches or relays in a catalogue and you'll soon see the
correlation betwen contact material and intended use)
--
Anahata
anahata@treewind.co.uk -+- http://www.treewind.co.uk
Home: 01638 720444 Mob: 07976 263827 |
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Laurence Payne
Guest
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| Posted:
Sat Nov 12, 2005 6:16 pm Post subject:
Re: Stage Box Idea |
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On 8 Nov 2005 11:08:53 -0800, "Thomas Bishop"
<bishopthomas@hotmail.com> wrote:
| Quote: | I have an idea to build some stage boxes at my church and wanted some
input (no pun intended). I would like to take the existing XLR plate,
punch some new holes for 1/4" jacks, wire in a transformer on each, and
have built-in direct boxes. My question is regarding the wiring:
Would it be better to use a switch to select one or the other signal
path or would the wiring (and only using one at a time) do the trick?
If I needed some type of switch, what should I be looking for?
|
I suggest you install standard XLR stage boxes and buy a few DI boxes.
Stage boxes get rough treatment. Keep them simple and robust. Your
idea has too many ways to break. |
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Thomas Bishop
Guest
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| Posted:
Sun Nov 13, 2005 5:42 am Post subject:
Re: Stage Box Idea |
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"Laurence Payne" <lpayne1NOSPAM@dsl.pipexSPAMTRAP.com> wrote in message
| Quote: | I suggest you install standard XLR stage boxes and buy a few DI boxes.
Stage boxes get rough treatment. Keep them simple and robust. Your
idea has too many ways to break.
|
I see more ways for a moving direct box to break, rather than one that is
mounted underneath a floor. These stage boxes are installed in a floor and
are not moved. Besides walking over the top of them (which is not rough
treatment), how do you mean? These are recessed about 4 inches into the
floor with a solid steel door that closes down over the top of it. There's
nothing that I can think of that would hurt these stage boxes or the
connections within. I'm going to try it out and see how it works before I
commit to buying 12 Jensen transformers, but I welcome all
comments/criticisms you may have. |
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Dale Farmer
Guest
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| Posted:
Sun Nov 13, 2005 12:45 pm Post subject:
Re: Stage Box Idea |
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Thomas Bishop wrote:
| Quote: | "Laurence Payne" <lpayne1NOSPAM@dsl.pipexSPAMTRAP.com> wrote in message
I suggest you install standard XLR stage boxes and buy a few DI boxes.
Stage boxes get rough treatment. Keep them simple and robust. Your
idea has too many ways to break.
I see more ways for a moving direct box to break, rather than one that is
mounted underneath a floor. These stage boxes are installed in a floor and
are not moved. Besides walking over the top of them (which is not rough
treatment), how do you mean? These are recessed about 4 inches into the
floor with a solid steel door that closes down over the top of it. There's
nothing that I can think of that would hurt these stage boxes or the
connections within. I'm going to try it out and see how it works before I
commit to buying 12 Jensen transformers, but I welcome all
comments/criticisms you may have.
|
YOu are going to need extra long guitar cords, to reach all the way to
the stage box from the various performer positions. This increased length
of unbalanced signal cable will pick up more EMI/RFI from the air. As
opposed to a short cable going to a portable DI near the performer.
These long guitar cords will be stepped on by everyone, more likely
to be yanked out mid performance by accident, and are one more different
kind of cable you will have to wrangle on deck.
I think this is, on the whole, not a good idea for a general purpose
space. If you have unbalanced signals being generated at the same spot
all the time, and you can locate the box right there, then this may be a
good solution for you. Location, location, location.
--Dale |
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