100v line kit

[Mr Steve]

Hi,

 

I'm putting together a basic 100v line mixer/amp and speaker set for a local school for them to cart round various outdoor events. Usual thing of two sets of a tripod with two horn speakers. I was going to plan to cable it as follows:

 

Mixer amp output > NL2 connector, NL2 splitter > NL2 connector with loads of cable to first speaker, short cable to second speaker (and the same out of the other splitter output, to the other tripod and it's other two speakers). This keeps things wired in parallel.

I wanted to keep the connections close to the amp, and thought that NL2 would be a pluggable connection but not run the risk of someone plugging in a more standard NL4.

The kit will be self contained, and not extended or modified. Would you deem an NL2 split acceptable for this, or is there a better way?

[paulears]

NL2's seem a sensible move, as you can't get an NL4 into an NL2 hole.

 

I think I might be tempted to just put two cables onto each speaker, and then use a back to back so you can daisy chain, rather than use the splitters, or have both - doesn't really matter.

 

I'd strongly suggest the kit goes in a rack with a back panel with sockets, to stop the physics teacher adding extra speakers to the wrong outputs.

[Mr Steve]

Thanks paulears. Yes - I'm going to put the mixer in a rack with a simple panel on the front, and the back blanked to prevent fiddling.

[TonyMitchell]

I get Paul's point on the NL2 thing, however the joining options are limited (AFAIK there is no NL4MMX equivalent in NL2 flavour).

 

Nothing to do with the cabling, but add to your shopping list a couple of sandbags to ballast the stand bases. Without them, the wind will always win, because of the typical surface area and shape of PA horns.

 

Also, a couple of rubber cable protectors for crossing walkways (a standard 9m cut in half is just the job).

 

 

 

[Mr Steve]

Good point about the ballast for the bases!

 

FYI, and NL2 will mate with an NL4MMX coupler. It's just the other way around that won't work (NL4 into a 2).

[boatman]

Just a thought, but wouldn't you be better to use an alternative connector to the Speakon. There's always the possibility that some unknowing person will bring along a couple of extra low impedance speakers and plug them in. Using an alternative non-compatible connector would prevent that.

[MarkPAman]

How about NL4 and use 1+ and 2- (or some other odd combination)?

[timsabre]

I don't think connecting an 8R speaker to a 100V line system would damage anything, it would just stop working until the offending speaker was disconnected.

 

The main problem I find with speakons is that people can't work out how to connect them, the requirement to twist usually defeats them and then they don't work.

[paulears]

Oldies amongst us will remember Vivien Capell's book from the 70s. There were no connectors, bits of wood with wing nuts, twisted flex, speakers had safety pins soldered on, and to connect, you simply pinned through the cable insulation, spaced enough not to touch. Add a bit of tape for waterproofing, and that was it. One of my first jobs was removing the pins, and blobbing with a soldering iron to reseal the insulation. Chopping a full reel of cable was the ultimate sin with the bosses! crock clips screwed to a board enable jack plugs to be connected simply for inputs, or bare wires - whatever you wanted. PA with horns was a cheap and simple way to earn a living. Battery operation popular, and banging poles into the ground much more common than stands!

[Paul TC]

Oldies amongst us will remember Vivien Capell's book from the 70s.

 

Some useful comments re 100V line systems and recollections here Previous recollections of Vivian Capell

 

edited to remove duplicate text

[AdrianW]

When I was 'cutting my teeth' doing PA jobs with Hospital Radio, we used EP4s on the 100V line stuff..... but then we did have a chief engineer who was ex TVS and worked out of an ex LWT OB truck that we had converted to PA use.

[mojo filters]

Oldies amongst us will remember Vivien Capell's book from the 70s.

 

I've got "Public Address Loudspeaker Systems" from 1990. It was given to me as a teenager by a kindly and helpful engineer who steered me away from buying cheap pressed steel drivers and piezo tweeters from Maplin as I built the 4th or 5th generation homebrew PA system, taught me how to build simple high-pass filters to protect proper tweeters and much more valuable advice - I've still got those boxes working today, though they weigh a ton compared with modern cabinets!

[sandall]

All my low-powered stuff still uses XLR-3s (pins at the speaker end), which were the preferred choice of the BBC, AKG, Bose, etc. before the arrival of the NL4. Not recommended in this scenario, because of the obvious danger of someone mistaking a mic for a speaker (or vice versa)!

 

Theatres used to use XLR-4s - 2 pins for low-Z, the other 2 for 100v, so you couldn't get it wrong (!). XLR-4s have the advantage that about the only things that use them are cue-lights, scrollers & some older PSU's, none of which are likely to be a problem in the OP's situation.