Seaside Greetings

[johnno]

Hello from John in sunny Blackpool, the breezy seaside resort on the west coast of England.

I'm a science technician in a secondary school and also have responsibility for the audio-visual resources which include the school hall's stage lights and sound gear. I've a degree in electronics but no experience of theatre tech.

A year 10 boy has been helping me so far but he just got himself promoted to Head Boy. I advertised today for pupils to assist me and one year 7 has already volunteered so its looking good. I'll have to spend the forthcoming summer holidays making up a course of study for him. Any one know any good books?

The hall is about 80' x 60' with 16' depth of stage having a 32' opening. The lighting board and dimmer are new(ish) with 24 DMX channels of 10A capacity but the sockets for the lanterns are mostly round pin 5A types, suggesting 1kW max loading. This makes me wonder how much I can safely plug in given the short-term intermittency and variable power loading of stage lights in use. Any suggestions?

Our lanterns are a mix of Strand (Patterns 23 & 263 Profiles, 223 Fresnels, 137 Flood, 60 Flood), Furse 1kW Fresnels, Parcans, CCT Minuette Fresnels and a TAS follow spot. Also we've got a full Cyclorama with asymmetric floods. (I recently visited another school that has nothing but (lots of) Parcans and preferred our set up despite its probable obsolescence: strangely shaped fixtures look good).

On stage there are two 12-socket overhead pipes using 3 and 5 channels respectively. FOH we have unwired ceiling mounted pipes at centre (4 sockets all with Parcans) and left/right stage (both 2 sockets), and a 3 socket bracket high on each side wall. A problem with all but the centre pipe is that the auditorium's lampshades obscure them. As these are giant hemispheres with a "pip" at the bottom the shadows they cast uncannily resemble lady's ti..er....bosoms (blush blush blush!). LOL. I'm thinking of dropping the lanterns about two feet on threaded rod in the hope of alleviating the problem.

We also use a digital projector to project "backdrops" onto the cyc. This was done for the first time earlier this year and was deemed successful despite once losing the radio senders signal and resorting to the projector manufacturer's bright purple splash screen. Oops! I had to tie the projector to the FOH centre pipe to do it but I'm asking for funding for a proper ceiling mount as the projector is used almost every week in school assemblies (from a trolley on the hall floor). I might get a signal wire installed if I can and do away with the sender.

Our sound system is crap. We haven't really got one. We've a couple of powered mixers (Carlsbro & Phonic) which are powerful enough but with just a speaker hanging on the wall each side of the stage opening there is a real intelligibility problem. We've three handheld mics and three two-channel radios with 5 lapel mics and one handheld. Some of the school's old boys offered to pay for a bit of upgrade but I'm struggling to get a decent sound and not sure where to spend the money to best effect. Any suggestions would be welcome.

The local Salvation Army hall has a beautiful Bose installation that sounds as divine as their mission. Fortunately jealousy is a sin so I just study catalogues and dream.

That's about it. Hi folks!

John.

 

[soundlight]

Welcome! You've found a true wealth of information and great people. About the course of study...actually, the idea of a teachers' section for the forum is being discussed right now. About the sound system, do you have a number on how much money they're willing to put up for it? That would help us decide what we'd reccomend to you. Again, welcome!

 

[cutlunch]

Hi John. Welcome to control booth it sounds like you are not too badly off with lights.

Just some questions for you.When you talk about your light bars you mention sockets. Do you mean the sockets are electrical sockets that go back to the dimmers. Are these sockets individually wired as seperate leads back to the dimmer or are some paired together so only one lead goes back to the dimmers. You also say one of the FOH is unwired but then you mention four sockets. I am slightly confused and without knowing exactly how things are wired it is hard to answer your question.

Also do all your lights have the 5amp plug or do they have 13 (15) amp plugs?

For example do the circuits that go back to the dimmers from the bars do they end in plugs you can put in any dimmer channel? Or are they hardwired to specific channels on the dimmers?

Do your dimmers have one or two sockets per channel? If your leads back from the bars have plugs on them are they 5A plugs or are they 13A plugs. If only 5 amps but your dimmers have 13 (or is it) 15 amp plugs then you could check with an electrician to see if it is legal to get a 13 (15 ) amp plug to two 5A sockets adapters made up. I would say from what you told us that the dimmers can handle ten amps which just means that you can plug in up to two 1k lights per dimmer cicuit. Sorry if that's confusing. It would be easier if you tell us what dimmer packs you have and maybe a photo or two.

I would probaly get the electrician for the school to have a look at it and see what cable rating has been run from the lighting bars. You may have to go to the board of governors and get the place rewired to current standards. If I have done my research right 5 amps are only two pin no earth. This doesn't sound that safe with all those metal cased lights.

I knew the USA was bad for different power connectors but I didn't know Britain was to. In theatre (also most other places) in New Zealand for single phase 240v the plugs/ sockets are all rated for ten amps. You can get 15 amp plugs and sockets but they don't tend to be used in lighting. More for heavy duty appliances. Then you go to 3 phase plugs and sockets etc. We also still have what is known as a tapon or piggy back plugs. These let you plug another plug into the back of one plug. They make rigging so much easier.

I had a thought on getting extra gear free / or cheap that you may have already thought of. Since you are in Blackpool have you approached any of the amusement parks or arcades and entertainment centres to see if you can get their old gear. Some of these places would probably update some of their lighting and sound gear every few years, between seasons, to keep it fresh looking. You might get some bargains.

Hope this helps.

 

[Chris15]

Now I have no idea about UK connectors, but I would not have thought it to be of any electrical sense to put an unearthed plug on a fixture that is not double insulated and so should be earthed.

And yeah, it does seem like us downunder (as far as I know, Australia & New Zealand use the same connectors - China also use our normal 240V 10A connectors, but that's another story...) have it easier in terms of plugs and sockets, but I think it might be a case of we think we have it easier. Have you actually seen the number of different plugs & sockets? The difference we find is that we really only use a limited number of them. Page 46 of this Clipsal catalogue gives some insight into connectors in production. This shows 24 different connectors! consider then the high current 3 phase connectors, the wielands, socapexs, etc. and it just gets messy.

 

[johnno]

Thanks for the welcome.

First off please be reassured that our installation is fully earthed 3-pin throughout and regularly checked by electricians.

The dimmer outputs are fly leads in a patch bay. The patch bay is wired to 10A round pin sockets on the ceiling or walls at the light positions.

We have two types of lighting bar. Type A has sockets built into it with their wiring running through the pipe's centre to a small distribution box at one end that connects the sockets to the dimmer channels allocated. Type B is a plain pipe with no integral electrics. In both cases the dimmer feeds are the 10A sockets described above.

The two pipes on stage and the centre FOH pipe are type A having 12,12 and 6 sockets built in fed by 5, 3 and 4 dimmer channels. All else is type B, simply offering a hanging point for lanterns adjacent to 2, 3 or 4 power sockets.

UK history lesson

Until the 1950s our homes had three different types of mains socket. All were 3 round pin and were either 5A, 10A or 15A rated. The now-standard 3 rectangular pin 13A socket was introduced to replace them all. Until the 1980s anything electrical you bought was supplied without a plug fitted on the grounds that the manufacturers had no idea what type of plug you'd need as four were in use. End of lesson.

Now, the stage here has six floor-level sockets for plugging in microphones: these use 5A sockets. The lights all connect via ceiling-level 10A sockets. The stage also has some floor-level power sockets that are fed from the patch bay. These are round pin and offhand I think they are 15A types (I'll check). There are also some standard 13A rectangular-pin power sockets direct from the mains. It's all good fun!

I like the idea of asking some of our public venues for old equipment and I've now got 14 volunteers to help me next term (12 Y7/8 and 2 Y10). It's looking good - I'll be able to put my feet up at last!

There is a lighting course for schools advertised by one of our suppliers (www.lancelyn.co.uk then click on Sales).

Regards
John.

 

[Peter]

It's looking good - I'll be able to put my feet up at last!

Good luck with that!!! Usualy the more volunteers, the more work for the person in charge too!

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