Opinions wanted on wiring installation

I have a friend who`s asked me to install some audio cabling in in furniture showroom, bar & outside for open air gigs.
The scenario is as follows:

Over the bank holiday next weekend he has 5 bands playing outside (weather permitting) This music needs to be piped to his showroom & also the bar. In a nutshell the system has to be flexible enough so that the source could be in any one of the 3 areas & be piped to the other 2 remaining areas. The people operating this setup are not technical in any way so it needs to be simple to re configure.


Logistics:

All areas are 50 meters away from each other so that the cabling needs to be balanced. The cabling will run from the outside area to the showroom & from the showroom to the bar. I`m thinking 4 pair cable so I have sends & returns in both directions from the showroom to the stage & the bar.

In the showroom the system will plug into a domestic hifi amp with unbalanced inputs.

The bar may well wind up having an unbalanced system.

The PA rig will have balanced outs from mixer.

What I`m thing is that the balanced outs of the mixer will have the balls to supply the outfronts & both other areas wired in parallel. So I need to unbalance the signals perhaps with transformers. Can anyone see a problem with this solution & what ratio transformers should I use.

Any thoughts would be appreciated.

I'm often asked to design stuff like this at my job. I've printed out your posting to digest along with my evening tea. I'll be back later with suggestions.

Oh, but I should ask you this: is a line-level distribution amplifier out of the question? That's really the proper way to do something like this.

Thanks for taking the time on this Dave, it`s appreciated.

Oh, but I should ask you this: is a line-level distribution amplifier out of the question? That's really the proper way to do something like this.

Click to expand...

A problem with a line level distribution amp is that the source could be in any of the 3 areas. This seems like a potential major rewire if the source moves. The people who are likely to be operating this need it to be quite simple, which makes it a bit more interesting to find a good solution.

Major rewire? Not at all. I'll be back later with a sketch. Operation will be very simple.

Thanks Dave

I gotta hit the sack now cos I`ve an early start tomorrow. So will pick this up in the morning.

Thanks again Dave,

this looks like the right solution. I`ll just have to get him to wear the cost now!!!!

This chap is selling a number of Grass audio DAs. This is a well-respected brand used widely in the US broadcast industry.

Here's one of the DAs he has for sale:

evilBay UK auction

Be sure to contact the seller and find out how many cards are actually loaded in the frame. It would be best if it were fully loaded, since you'd have more spares if any cards go south :grin:

There's also this if you want something with XLRs on it.

Usual disclaimer: I don't know these people, I don't know the condition of the equipment, I have no involvement in these auctions.

Having had a bit more time to digest the circuit, your solution seems so obviously the right one to me. With regards to the distribution amp that looks like a major cost to buy a commercial product, which may put my friend off this solution.

Could I build my own :
using the balanced input circuit from the GSSL & feed that to 3 output circuits. This uses the 5534 to unbalance the signal & 5532 to create + & - balanced signals. Am I right in saying these chips can feed long cable lengths. Other than that I suppose the ssm2142 is another option.

Rob, see my post above. Second-hand DAs can be had rather cheaply.

Otherwise, the plan you describe will work fine. The 5532 is a good line driver. Be sure to use small resistors (about 47 ohms) in series with each output, outside the feedback loop.

It looks like your friend's budget won't permit, but you always have the option of going with a matrix system like:
http://mediamatrix.peavey.com/home.cfm
http://www.bss.co.uk/includes/product_list_include.aspx?header_id=1&archived_flag=0
http://whirlwindusa.com/edesk.html

I use media matrix in one of my gigs and it is dead solid and only uses a few cat5 cables. It can get as simple or as complex as you want it. A little expensive.. But you may be able to find some stuff like that for a better price...

hope it helped.
Gil

Thanks Dave & BR

The ebay links look promising, although I definately won`t be bidding on the Broadcast Supplies one because I`m fairly sure this guy used to trade under a different name & ripped me off badly when I got some B gauge jackfields from him. I`d like to meet him face to face, but he hides behind a Post Office box number.

The Alice box looks to fit the bill nicely & even new its only about £170 which sounds a lot better than £300 for the other brands I was looking at.

BR
The matrix systems look really versatile, but I think would possibly be too expensive & rather over the top for this particular job, where the emphasis has to be simplicty.

Thanks again

[quote author="Rob Flinn"]Thanks Dave & BR

The ebay links look promising, although I definately won`t be bidding on the Broadcast Supplies one because I`m fairly sure this guy used to trade under a different name & ripped me off badly when I got some B gauge jackfields from him.
Thanks again[/quote]
The broadcast supplies geezer... had dealings with him.. like pulling the auction just before I won by saying he listed it wrongly..

Anyway.. Rob did you know an ex employee of Alice has joined the forum and is posting ...
(hint....
think green now red, meek now ted type things)

Got hold of the Alice distribution amp today, it`s a nicely made bit of kit. I`ll be installing it tomorrow.

NYD

Finally finished install about an hour ago. It works a treat. A big thankyou for your help with this :guinness: :guinness: :guinness: :guinness:

Glad I could help! :thumb:

yep
distribution amps
are my bread and butter

when your facility gets large enough, they can make life much easier
and once you have seen the merits of them
you may want them in even your smallest set-up

we like DA's
... ADAs, SDAs, VDA, DDA's ... RE-clocking DDA .... etc
:thumb: