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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Tommy Peel on January 08, 2014, 06:07:29 pm

Title: Mixer Rack Case Power Distribution
Post by: Tommy Peel on January 08, 2014, 06:07:29 pm
I've had this mixer rack for a while now and currently my power distribution consists of the 5 power cords coming out of the case and going to a 6-outlet Walmart power strip....
(http://i.imgur.com/MGx9Lh6.jpg)
(http://i.imgur.com/SjVIWVc.jpg)
(http://i.imgur.com/gk6gyI0.jpg)

Anyway I'm thinking of getting a rack mount power strip or finding some other better solution(one cord coming out of the rack going to the wall). I found these on Amazon but am open to other suggestions that are <$50. In my situation(all analog gear) a UPS would be overkill and out of the budget.
Cyberpower CPS-1215RM (http://www.amazon.com/dp/B00077IG3O/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=ZI8F3LURZ6PM&coliid=ITBJYKHP0HM15)
Tripp Lite RS1215-RA (http://www.amazon.com/Tripp-Lite-RS1215-RA-Rackmount-Outlet/dp/B00006B834/ref=pd_cp_e_2)
Title: Re: Mixer Rack Case Power Distribution
Post by: Mike Sokol on January 08, 2014, 08:03:53 pm
Anyway I'm thinking of getting a rack mount power strip or finding some other better solution(one cord coming out of the rack going to the wall). I found these on Amazon but am open to other suggestions that are <$50. In my situation(all analog gear) a UPS would be overkill and out of the budget.
Cyberpower CPS-1215RM (http://www.amazon.com/dp/B00077IG3O/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=ZI8F3LURZ6PM&coliid=ITBJYKHP0HM15)
Tripp Lite RS1215-RA (http://www.amazon.com/Tripp-Lite-RS1215-RA-Rackmount-Outlet/dp/B00006B834/ref=pd_cp_e_2)

If I were picking from these two I would select the Tripp-Lite for two reasons. First, Tripp-Lite is a well known manufacturer who stands behind their products. I don't know about CyberPower since I've never seen any of their other products or know anything about them. Second, I like that the Tripp-Lite strip has 6 outlets on the back and 6 on the front. You always need a few front outlets for an iPhone charger, soldering pencil, whatever.

Now it doesn't bother me much that neither of these boxes are "surge strips" which I consider to be a highly overused and misunderstood term. If you really need to protect sound gear from "surges" a couple of MOVs in a cheap power strip won't do much. In that case you'll need to spend about 10 times your budget on a Surge-X or something similar. Of course if you have a digital mixing console worth thousands or even 10's of thousands of dollars, then spending  hundreds of dollars on a high-end surge protector and/or UPS makes sense. But the subject of surge protectors and UPS backup should probaby become its own thread.   
Title: Re: Mixer Rack Case Power Distribution
Post by: Frank DeWitt on January 08, 2014, 08:49:31 pm

Now it doesn't bother me much that neither of these boxes are "surge strips"

I think a surge protector on a sound system (as opposed to a Surg-X) is worse then nothing.  Here is why.

Assume a bunch of equipment at FOH on a surge protector.  Assume equipment on stage or back stage (Amps for example) with or without a surge protector.  Now assume the FOH takes a hit.  Perhaps a nearby lightning hit is coupled to the system.  OK, the surge protector dumps all that voltage to ground.  The ground at the FOH is connected to the panel with wire that has resistance.  That means that for an instance, the voltage between that ground, and the ground at the panel went up.  Perhaps way up.   (Ohms law)  There are some audio lines between the FOH and the Amps out back.  One end of the audio lines is at FOH ground, the other end is at stage ground (no hit at the stage.)  BAM  a bunch of voltage on pin 1 at the stage so that equipment can share in the destruction.

SurgeX is different.  It doesn't dump a hit to ground.

Flame suit on.
Title: Re: Mixer Rack Case Power Distribution
Post by: David Sturzenbecher on January 08, 2014, 09:46:14 pm
I have found great deals on SurgeX products on ebay.  With how good they are there doesn't appear to be much demand.
Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on January 08, 2014, 09:47:46 pm
From reading previous threads I'd gathered that surge "protectors" were over rated(SurgeX and similar gear excluded) and likely to cause issues so I was already quite happy that both were just power strips. ☺

Mike, I was leaning towards the Tripp-Lite for the same reasons so that's probably what I'll end up doing.

Also in relation to surges this gear is plugged in maybe 30hrs a week(and unplugged between setup night and church night if the weather looks bad) on average. The rest of the time it's packed in a side room; if it was all plugged in all the time I would be getting something more substantial(SurgeX or nice UPS).

Sent from my Nexus 4 running OmniROM 4.4 KitKat using Tapatalk Pro

Title: Re: Mixer Rack Case Power Distribution
Post by: Jonathan Johnson on January 08, 2014, 11:43:47 pm
Since most high-energy surge voltage (read: lightning strike) is likely to come from outside the building, a panel-mount surge protector in the electrical service entrance will probably provide better protection than any run-of-the-mill power strip could hope to do.

Of course, that won't necessarily protect you from localized surge sources on the same circuit or subpanel.
Title: Re: Mixer Rack Case Power Distribution
Post by: Lyle Williams on January 09, 2014, 02:21:44 am
Make sure a rack mount power strip fits.  You need enough free depth behind it to install it, and you need enough space in front of it to leave gear plugged in with the roadcase closed.

For me the power strips that mount flush with the rack rails are too far forward.  With power plugs inserted the covers don't fit back on the case.

Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on January 09, 2014, 02:52:52 am
Make sure a rack mount power strip fits.  You need enough free depth behind it to install it, and you need enough space in front of it to leave gear plugged in with the roadcase closed.

For me the power strips that mount flush with the rack rails are too far forward.  With power plugs inserted the covers don't fit back on the case.
Good point, right now all the stuff that'll stay plugged in will fit in the rear outlets but I'll have to make a few measurements to make sure everything fits. I'll also want to get some short(1ft maybe??) IEC->Edison cables to get everything plugged in neatly.

Sent from my Nexus 4 running CNA 4.4 KitKat using Tapatalk Pro

Title: Re: Mixer Rack Case Power Distribution
Post by: Lyle Williams on January 09, 2014, 03:47:14 am
Sometimes you can sit a power strip behind the rack rails, using a stack of washers as spacers and long bolts.  This is easiest to do if the power strip is the first thing into the rack.
Title: Re: Mixer Rack Case Power Distribution
Post by: Doug Johnson on January 09, 2014, 06:23:50 am
I never verified this information but, I was once told by an electrician that the MOVs in surge protectors can in some circumstances leak voltage on to the ground, causing GFCIs to trip.
Title: Re: Mixer Rack Case Power Distribution
Post by: Mike Sokol on January 09, 2014, 07:27:00 am
I never verified this information but, I was once told by an electrician that the MOVs in surge protectors can in some circumstances leak voltage on to the ground, causing GFCIs to trip.

That is correct. MOVs in cheap surge strips will typically have 2 or 3 mA of leakage from the line to the safety ground. So plugging one "Surge Strip" into a GFCI with a 5 mA threshold won't trip by itself, but plugging two Surge Strips into a GFCI outlet may result in a random trip, even if none of your gear has a ground leakage problem. Here's a pair of No~Shock~Zone articles I wrote on GFCI theory and troubleshooting:

http://www.noshockzone.org/rv-electrical-safety-part-viii-gfci/

http://www.noshockzone.org/rv-electrical-safety-part-x-%E2%80%93-gfci-troubleshooting/
Title: Re: Mixer Rack Case Power Distribution
Post by: Cailen Waddell on January 09, 2014, 11:26:58 am
We use the Tripp light strips in all of our racks. We like them.
Title: Re: Mixer Rack Case Power Distribution
Post by: Jamin Lynch on January 09, 2014, 12:54:32 pm
Mike,

I've heard that the typical surge protector will not protect you from a lightning strike because it is too slow to react. By the time the surge protector trips, the lightning has done its damage.

Is that true?

Thanks
Title: Re: Mixer Rack Case Power Distribution
Post by: Jonathan Johnson on January 09, 2014, 02:23:51 pm
I've heard that the typical surge protector will not protect you from a lightning strike because it is too slow to react. By the time the surge protector trips, the lightning has done its damage.

The problem is most surge strips don't necessarily "trip." The MOVs shunt excess voltage to ground, which *may* act as a short circuit and trip the built-in breaker, but it might not trip the breaker. And once the capacity of the MOV has been used up (they are a sacrificial element), you have no protection at all while power still flows.

If the MOV does pass enough current to trip the breaker, chances are good that the surge voltage is high enough to arc across the contacts of the breaker and anything else in the strip which could lead to an explosion of the device.

EDIT: For Mike's answer, look here: http://forums.prosoundweb.com/index.php/topic,147759.0.html
Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on March 25, 2014, 01:07:13 pm
To follow up on this topic, I finally bought and installed the aforementioned Trip-Lite unit in my rack. It helped clean things up in the rack a bit though, because of the length of most of my in-rack cables, it's still more of a mess than I'd like.

(http://i.imgur.com/U66lAk9.jpg)

(http://i.imgur.com/p6UqZTd.jpg)

(http://i.imgur.com/PVxQpaS.jpg)

(http://i.imgur.com/D7Ckpu0.jpg)

(http://i.imgur.com/VXcZOqs.jpg)
Title: Re: Mixer Rack Case Power Distribution
Post by: Frank DeWitt on March 25, 2014, 08:38:06 pm
To follow up on this topic, I finally bought and installed the aforementioned Trip-Lite unit in my rack. It helped clean things up in the rack a bit though, because of the length of most of my in-rack cables, it's still more of a mess than I'd like.


You can buy 12 or 18 inch power cords on Ebay

Frank
Title: Re: Mixer Rack Case Power Distribution
Post by: David Sturzenbecher on March 25, 2014, 11:08:19 pm

You can buy 12 or 18 inch power cords on Ebay

Frank

Or monoprice.com 1ft, 2ft, 3ft increments in 14, 16, or 18 AWG
Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on March 26, 2014, 12:01:28 am
Or monoprice.com 1ft, 2ft, 3ft increments in 14, 16, or 18 AWG


You can buy 12 or 18 inch power cords on Ebay

Frank

Yeah I may have to pick some of those up. Monoprice is pretty cheap.  More of a problem than the power cords though are the 10ft 4ch insert snake, 2-10ft insert cables and 4-10ft trs cables... I bought all of those when the outboard was in a separate rack and haven't replaced them with short ones yet. Does anybody know a source of cheap, short(~18in) 1/4in insert cables? Monoprice doesn't carry them.

Sent from my Nexus 4 running OmniROM 4.4 KitKat using Tapatalk Pro

Title: Re: Mixer Rack Case Power Distribution
Post by: Frank DeWitt on March 26, 2014, 09:38:58 am
Perfect opportunity to polish your soldering skills.  If you have no soldering experience to start with, poke around your church.  someone there knows how to solder.

It is a very handy skill for a sound tech.
Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on March 26, 2014, 11:48:44 am
Perfect opportunity to polish your soldering skills.  If you have no soldering experience to start with, poke around your church.  someone there knows how to solder.

It is a very handy skill for a sound tech.
I suppose so. I've done a fair amount of soldering and I guess the advantage of building my own is I can custom make the lengths. I might even make a custom panel for my outputs(which have to be TRS to XLR).
Title: Re: Mixer Rack Case Power Distribution
Post by: Taylor Hall on March 26, 2014, 12:15:51 pm

Yeah I may have to pick some of those up. Monoprice is pretty cheap.  More of a problem than the power cords though are the 10ft 4ch insert snake, 2-10ft insert cables and 4-10ft trs cables... I bought all of those when the outboard was in a separate rack and haven't replaced them with short ones yet. Does anybody know a source of cheap, short(~18in) 1/4in insert cables? Monoprice doesn't carry them.

Sent from my Nexus 4 running OmniROM 4.4 KitKat using Tapatalk Pro

We've had good luck with their small patch cables (both XLR and TRS) and they've served us well. We have a bunch of their 3ft XLRs that we use for our DSP patching to amps and they've been rock solid. Only downside is that they're a bit fiddly when it comes to servicing as they put in some electric putty/goop to seal everything together. Great for keeping connections solid, bad for when you need to rewire it on the fly. That being said, these never get moved around so YMMV.
Title: Re: Mixer Rack Case Power Distribution
Post by: Tommy Peel on March 26, 2014, 12:38:22 pm
We've had good luck with their small patch cables (both XLR and TRS) and they've served us well. We have a bunch of their 3ft XLRs that we use for our DSP patching to amps and they've been rock solid. Only downside is that they're a bit fiddly when it comes to servicing as they put in some electric putty/goop to seal everything together. Great for keeping connections solid, bad for when you need to rewire it on the fly. That being said, these never get moved around so YMMV.

Yeah, I've got a few of their short patch cables in that rack(along with the other too long ones). They work fairly well, but I don't like their mic and instrument cables. They're too thick and don't seem to hold up well. I just wish they made a 1/4in TRS to dual TS cable for my inserts. 6-2ft(instead of the 10ft ones I have now) insert cables would clean that rack up a lot.

Sent from my Nexus 4 running OmniROM 4.4 KitKat using Tapatalk Pro

Title: Re: Mixer Rack Case Power Distribution
Post by: Mike Sokol on March 26, 2014, 01:15:00 pm
Perfect opportunity to polish your soldering skills.  If you have no soldering experience to start with, poke around your church.  someone there knows how to solder.

For those of you interested in learning how to solder, here's a primer I wrote on the subject for PSW a few years ago:

http://www.prosoundweb.com/article/church_sound_maintenance_dont_be_afraid_soldering_isnt_scary/ (http://www.prosoundweb.com/article/church_sound_maintenance_dont_be_afraid_soldering_isnt_scary/)
Title: Re: Mixer Rack Case Power Distribution
Post by: Frank DeWitt on March 26, 2014, 01:34:05 pm
For those of you interested in learning how to solder, here's a primer I wrote on the subject for PSW a few years ago:

http://www.prosoundweb.com/article/church_sound_maintenance_dont_be_afraid_soldering_isnt_scary/ (http://www.prosoundweb.com/article/church_sound_maintenance_dont_be_afraid_soldering_isnt_scary/)

Let me add to that good article, if you are going to solder more then 3 or 4 times a year then buy a temperature controlled soldering station.  It is one of those tools that I waited to long to buy.  My reaction the first time I used it was How about that, I really do know how to solder.  How much difference does it make?  I have a soldering pencil in my tool bag.  but if I know I am going to be soldering I will pack up the soldering station and take that with me.

One other trick.  Use small diameter solder. (.031 inch is good)

You can get a off brand soldering station starting at about $30
Title: Re: Mixer Rack Case Power Distribution
Post by: Taylor Hall on March 28, 2014, 12:06:27 pm
Why go off-brand when you can get a Weller for $39?

http://www.parts-express.com/weller-wlc100-soldering-station--372-120