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Poor Man's Bar Distro

 

When providing sound, we small-timers must use standard wall outlets instead of being able to tie a power distro into the main breaker as is the practice in large scale shows.  A common problem is that the grounds of the AC outlets are not at the same potential, which causes a ground loop in the system.  The Poor Man's Bar Distro improves or solves this problem.

The distro is comprised of four sections, each section having a Neutrik PowerCon Inlet, Outlet, and Jumper Outlet (which can also be used as a second outlet).  Each sectionís I, O, and J are wired in parallel.  Each section is rated 20 amps total input/output (or as limited by each house Edison supply outlet Ė often 15amps).  The grounds of all the PowerCons are bonded (connected) to the chassis, so that all of the grounds are at the same potential, to reduce or eliminate the possibility of mains-caused ground loops.  All of the above will fit on a single pre-punched one-space rack panel, but itís best to build it into an enclosed metal chassis.  This setup will allow maximum usage of the electrical supply of the typical bar, small theater, or corporate meeting venue.  (No two sections that are fed by House outlets can be connected together, so no sparks.)

Owing to a lack of space in my equipment racks, I never envisioned that the distro would be mounted in one.  Should you wish to do so, you could of course mount Edison outlets on the back of the distro.  This would eliminate the need for power strips in the rack.  As Decora Edisons mount in a single rectangular hole, that would be the easiest solution - unless you can find cost effective round outlets (which used to exist - I've not looked in recent years).

Follow-up:
I later found that my hum problems were not a loop at all, but an open negative signal conductor in one of the sub lines of my drive snake (sometimes I used one sub line, sometimes I used the other).  (Check your cables once in a while!)  I discovered this when I chopped the 100' drive snake into four 25' sections.  Three of the four sections were open on that conductor!  I've never seen anything like it.

 

After a couple of years of thinking about building this thing, I remembered that I had an oddball 1.5 space rack left over from a trade I made back in the '80s, so I finally built it

 

How to use it:

In all Scenarios (A, B, C, D), connect each load to a section Output:

Section 1 Output to Amp Rack One.

Section 2 Output to Amp Rack Two.

Section 3 Output to FOH, etc.

Section 4 Output to band power stringers, etc.

Now, we configure the Inputs (and Jumps) if applicable).

A)  House has four Edison outlets available:

House outlet 1 to Section 1 Input.

House outlet 2 to Section 2 Input.

House outlet 3 to Section 3 Input.

House outlet 4 to Section 4 Input.

 

 

B)  House has three Edison outlets available:

House outlet 1 to Section 1 Input.

House outlet 2 to Section 2 Input.

House outlet 3 to Section 3 Input.

Section 3 Jump to Section 4 Input.

 

 

 

 

C)  House has two outlets available:

House outlet 1 to Section 1 Input.

Section 1 Jump to Section 2 Input.

House outlet 2 to Section 3 Input.

Section 3 Jump to Section 4 Input.

 

 

D)  House has only one outlet available:  

House outlet to Section 1 Input.

Section 1 Jump to Section 2 Input.

Section 2 Jump to Section 3 Input.

Section 3 Jump to Section 4 Input.

 

Again, any unused Jump can be use as an additional Out.

 

Shown below with the Jumpers for configuration D

 

12 gauge wire inside (which is likely overkill given the lengths involved).
The one that disappears in the lower left corner is the chassis ground.

 

 

Parts Needed

The PowerCon Chassis Inlet is part number NAC3MPA.

The PowerCon Chassis Outlet is part number NAC3MPB.

The PowerCon Cable connector for the power input is NAC3FCA.
You'll need one for each Edison to PowerCon feed, and one for every jumper.

The PowerCon Cable connector for the power output is NAC3FCB.
 You'll need one for every output cable, and one for every jumper.

(Also see my AC Cables page and my Rack Stuff page.)

As to the chassis, try:

http://www.wolgrammfg.com/products/ruSeries.html

http://www.smarthome.com/8735c.html

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=262-430
(other sizes are available)

 

 

 

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