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[James]

OK,

 

It appears to have been a bit quiet arround her for the last couple of days, so I thought I would ask a trio of questions - sorry to the moderators if they are in the wrong threads though.

 

1)

 

I use a Gemini for lighting, I know it's old but I got it at a very reasonable price and it more than does the job HOWEVER it's only D54, I've just invested in some small scans for up-beat shows & bands. My problem is do I

A: Buy a little tiny controller just for scans

B: Buy a medium controller for everything for small shows

C: Buy a replacement for the Gemini for everything.

(Obviously money is tight, and I would have to wait and hire in the intrim for the expensive options)

 

2)

 

I had the bolt of a lantern drop on me on Saturday at the "death trap" venue (see safety forum for on tap rants) This one was caught by the safety.

 

I have to assume it wasn't done up properly when rigged. This was a disco effect (That the ejit had rigged on a dimmer as well (Grrrr.) ) But it was rigged on wednesday.

 

There were no washers - would this and the heat - fan - motion of the effect contributed to it falling.

 

Has anyone else experienced a lamp fail at the hanging bolt two days after rigging?

 

3)

 

I am looking for work in the south london (Merton - Sutton - Croydon) region. I have my own (small) rigs, and just want some work - I'm willing to work for nothing if neccesary to begin with as I'm just bored. Any ideas on anyone looking for help in the area?

 

4)

 

Amaters, I read the thread when it came round, and I was a bit sceptical but in the last few days I'm ready to believe anything, the guy brought in by the house was a student at a performing arts college, Apart from riging (unsafely) a disco light on a dimmer - his sound technique was crank the gain to the top "Beccause it's a mic you know??" so that it clips to .... Run the amps @ 50% and push the output of the desk to cliping (with line sources)

 

And he is one year into a 2 year course. He also took great delight in being called a technician.

 

 

Anyway, I appear to have taken off on one here, sorry for the rant but It wasn't a good couple of evenings.

[Thirdtap]

use a Gemini for lighting, ....... D54, ..............scans........

 

'Lo

I thought I saw a couple of D54 to DMX multiplexer on some second hand lists. I think some compainies might still sell them because of the large market in strand desks.

 

I would think that keeping everything one desk was the best for total control - blackouts and such like.

 

As for the bolt dropping out of the lantern. I had a conversation recently with a few friends and no one had any experience of this sorta thing happening.

 

Hope ya head is ok..

[James]

I thought I saw a couple of D54 to DMX multiplexer on some second hand lists. I think some compainies might still sell them because of the large market in strand desks.

 

Hmm,

 

I looked for some of those when I got the desk - 'bout a grand each but that was new.

 

The thinking then was I could get a beh****er for £180 or upwards from there.

 

Head is OK, Heart almost wasn't - was about 2' from me - I was videoing the event with brand new camera, and there were a lot of young people on the dance floor.

[James C]

'Had a similar narrow escape in a school a couple of years ago. Just got up from a chair in the staff room when a monkey wrench landed on the seat I'd just left! A contractor working above the false ceiling dropped it, and it went straight through a panel of whatever ply/chipboard the ceiling was made of like the proverbial buttery knife! Never thought to make a fuss at the time - to be fair, most people would probably assume a lanyard wasn't necessary when there was a ceiling between them and the room below, but 5secs earlier and I'd have had a substantial gooey hole in my cranium <_<

[Dave]

James,

 

I had the bolt of a lantern drop on me on Saturday at the "death trap" venue (see safety forum for on tap rants) This one was caught by the safety.

 

I have to assume it wasn't done up properly when rigged. This was a disco effect (That the ejit had rigged on a dimmer as well (Grrrr.) ) But it was rigged on wednesday.

 

There were no washers - would this and the heat - fan - motion of the effect contributed to it falling.

 

Has anyone else experienced a lamp fail at the hanging bolt two days after rigging?

You don't exactly give the specifics of this rather dangerous incident. If you have any more information, please tell us.

 

I will assume that the disco light was suspended from by a nut and bolt (attached to a hook clamp?), and the nut undid itself completely, causing the unit to fall.

 

I have never known this to happen in the 20+ years that I've been doing lights. However, most of my work is theatrical and I avoid disco lights like the plague.

 

The most likely reason is vibration from the motors in the light. I would also expect that the nut was not done up tightly to start with.

 

The only other cause could be thermal, ie repeated heating and cooling causing expansion and contraction of the metal. Although this could possibly cause a nut to loosen, I can't see it resulting in something unscrewing completely, and certainly not in a couple of days.

 

Normal washers will not make a difference in my opinion, and spring washers are also unlikely to do much. The use of shake-proof washers (in the right places) would help, though, as these have serrations that prevent things turning. Note that the serrations can become flattened and ineffective with repeated use.

 

I use nylon lock nuts (aka nyloc nuts) on all my lanterns, so there is no way that they can undo themselves, and it makes focussing easier as well.

 

Hope this helps,

 

Dave

[James]

You don't exactly give the specifics of this rather dangerous incident. If you have any more information, please tell us.

 

I will assume that the disco light was suspended from by a nut and bolt (attached to a hook clamp?), and the nut undid itself completely, causing the unit to fall.

 

Exactly, 2" bolt, Wingnut, got seperated causing lantern to fall and get caught by safety chain.

 

The most likely reason is vibration from the motors in the light. I would also expect that the nut was not done up tightly to start with.

 

http://216.71.107.24/WEB%20EFFECTS%20LIGHTING/BURST.JPG

 

This was the style of light.

 

It was hung verticaly downwards and run off a dimmer - It was obvious to an outsider that it didn't like this as the motor kept jerking and stuttering.

 

I use spring washers on all my lights and I have never had one work loose.

[martinw]

I thought I saw a couple of D54 to DMX multiplexer on some second hand lists. I think some compainies might still sell them because of the large market in strand desks.

 

Please don't even think about trying to run moving lights using a D54 signal and a DMX convertor.

 

D54 is an analogue multiplex. It works by sending a voltage between 0 and 5V (I think) representing the channel 1 level, for a small fraction of time, and then channel 2 and so on and on. The demultiplexer units work by storing this level in a capacitor using a sample-and-hold circuit.

 

D54 to DMX conversion units work by sampling this stream of analogue levels, and converting them back into 8 bit digital values, which form the DMX output. Each of the 256 possible DMX values represent about 0.02V difference on the incoming analog signal, so it takes only a little interference for the converted value to change. On top of this, I don't think D54 is balanced (correct me if I'm wrong, Its been a while...), which will make it even more prone to noise.

 

All of this is fine for dimmers, and you probably won't notice the flicker anymore than you would on a 0-10V non-multiplexed analogue system, but if you digitise this signal, and try to control a moving light, you may have great trouble trying to get the mirror to keep still, as it will try to 'follow' the noise on the signal.

 

Strand once made a DMX512 output card for the Gemini, although I can't remember if this was Gemini 2 only. You should be able to pick one up quite cheaply, try Stage Electrics, or other Strand dealers as they probably have one kicking around. Auctions may also be worth a bet.

 

Regards

 

Martin

[Thirdtap]

Yep had a look during company time to try and find where I saw D54 to DMX multiplexers, but no luck. As far as a I got was Stagetec in Slough that deals with compulite stuff.

 

Found tech info but no prices it might be worth contacting the company I have always found them helpful.

 

Here's the link hopefully anyway.

Stagetec

 

 

<_<

[Brian]

forget the Gemini for wiggly light.

 

You can pick up a cheap DMX controller designed for moving lights for around £150. Most will do 12 fixtures each with 16 channels of DMX.

 

You see some on e-bay uk but many more on e-bay Germany, www.ebay.de.

[James]

You see some on e-bay uk but many more on e-bay Germany, www.ebay.de.

 

Thanks - never thought of looking in germany.

[Brian]

Thanks - never thought of looking in germany.

 

If anyones German is not up to it...

 

www.ebay.de

 

go to Audio and Hi-Fi (easy that one)

go to Licht und Effekte (still easy)

go to Lichtsteuerungen (aha, not so easy now = lighting controllers)

 

you find quite a lot of lighting stuff on e-bay Germany, many people will ship within europe, look for 'Versand nur nach: Deutschland' = only ships to Germany or 'Versand nur nach: Europe' = ships to Europe, 'Versand in alle Länder (weltweit)' = worldwide.

 

Have a lokk under the Licht und Effekte section for all the subsections.

 

Also for anyone who can't work it out 1T 05Std 21Min is 1 day 5 hours 21 minutes.

[Thirdtap]

From martinw - D54 is an analogue multiplex.

 

You learn something new everyday. I was under the impression that D54 was an early digital system I'm sure I was told asa much at college many years ago.

Thanks for the information.

[MarcT]

I'm not sure if this is likely (or even possible) - but it wasn't anything daft like using a metric bolt and an imperial wing-nut (or vice-versa) was it?

 

I imagine vibration could cause that combination to come undone.

 

Marc

[robloxley]

I use a Gemini for lighting, I know it's old but I got it at a very reasonable price and it more than does the job HOWEVER it's only D54, I've just invested in some small scans for up-beat shows & bands. My problem is do I

A: Buy a little tiny controller just for scans

B: Buy a medium controller for everything for small shows

C: Buy a replacement for the Gemini for everything.

Or D: Try and find a DMX output card for a Gemini.

 

But whether you really want to run wobbly lights from a Gemini is another question...

[James]

I'm not sure if this is likely (or even possible) - but it wasn't anything daft like using a metric bolt and an imperial wing-nut (or vice-versa) was it?

 

I imagine vibration could cause that combination to come undone.

 

Marc

 

Don't know if the guys there looked into that kind of thing will ask