Dimming Fluorescent Tubes

[Ian_P]

Hi,

 

Is there any simple ways to allow a standard dimmer pack to dim flurescent tube lights?

 

I want to use these tubes to make a light box behind a set window and there is only about 12" clearance, so normal lanterns can't get in there.

 

Any ideas?

 

Cheers.

[Tom]

You can get DMX controlled dimable fluorescence but they cost between £25 - £35 a pop to hire. Sparks (in London) do some good ones.

 

An alternative route would be to use architecturals - basically long thin tungsten bulbs. They can be run off standard dimmers and would probably look better than flori's (IMHO).

 

Or - you could probably get a couple of small sun floods (very cheap) in there and bounce them off something...

[Guest lightnix]

Dimmable fluorescent ballasts are easy enough to find, most electrical wholesalers should have them.

 

You could also try adding a 1k load lamp to the circuit and hiding it somewhere.

[Ian_P]

Thanks,

 

I take it from this that you mean that changing the ballast unit in a florry unit for a dimming one will allow me to dim these from a standard dimmer unit - excellent!

 

And if a have another lantern there as a load instead, that will allow dimming too.

 

My only question would be would these dim right out or could they flicker like when a tube is switched on? (I would not want a flicker)

 

Cheers - and sorry for all the questions!

[Guest lightnix]

The last time I used dimmable ballasts (or indeed had to dim florries) was about 15 years ago. They were OK, but there was flicker at around 30%, presumably th technology has improved since then.

 

The load lamp solution is a bit of a botch, to be honest, and more flicker prone.

 

In the end you get what you pay for.

[DanielArkley]

We have some flourescent tubes at school for our house lights (yuck). When we try and dim them, they seem to flick on and off as we turn the dimmer switch, and you get really bad "strobe" kind of effect when they are turned lower than about halfway.

 

Hope this helps.

[Thirdtap]

...and you get really bad "strobe" kind of effect when they are turned lower than about halfway

 

At a previous place of work we had dimmers on the house flos. Never used them for a show thou because the light switches were placed in really odd places.

Found when you dim the lights at about 60 - 70 % the light starts going grey and making you look very ill.

[Grum]

I take it from this that you mean that changing the ballast unit in a florry unit for a dimming one will allow me to dim these from a standard dimmer unit - excellent!

 

And if a have another lantern there as a load instead, that will allow dimming too.

 

My only question would be would these dim right out or could they flicker like when a tube is switched on? (I would not want a flicker)

 

If you buy a dimming florry ballast today then the chances are it will require an analogue (0 - 10 volts) signal to dim. Hardly anyone makes phase dimmable ballasts (the sort you just plug into the dimmer pack) anymore, if you look at most florry units they run off DMX.

 

The best thing to do is wire up the florries with dimmable ballasts and give them an analogue signal (from a dmux or similar) then you will need to give them a hard power supply (non dimmed) and a control signal (if you use XLR type connectors it will make setting and striking quick and easy).

 

Flicker when you turn them on is unavoidable, most units come on at 10 - 20% so the best solution is to turn them on and leave them as dim as possible (10 - 20% is barely visible unless you in a blackout)

 

As for flicker when dimming, this is not a problem with most modern ballasts (its good enough for a lot of TV people).

 

You wont need a load lamp either.

 

 

Grum

 

P.S.

If anyone knows where you can get phase dimmable ballasts please let me know.

[themadhippy]

can you still get cathode heater/transformers? ,our very ancient units have these alongside a normall ballast(I think) and not olny are they dimable but no flicker and instant starting,ill try and dig out some details on them

[stebee]

Hippy,

 

did you have any luck with this, cos I know I'd be interested in getting flouries to dim without flicker.

 

we use some ERCO ones in our gallery that flicker wven when switched off. when we use them in the theatre we put a load lamp on but they still dont strike until about 22%- 30%

 

ste

[MattH]

Hi Guys,

 

I've built dimming flourie stuff a few years ago, the phase method lets you plug them into a pack, although the trick in them not flickering is to apply a heater voltage to each end of the tube (about 4.5V - from the top of my head).

 

I'm not sure how the newer stuff works, but I'll ask a colleague who was once Flourie King and get back to you. Maybe you could combine the two?

 

Matt

 

PS Grum, I think Helvar were the last people to make them?

[Guest lightnix]

Keith Owen and Dave Smith of Specialz have developed a dimmable ballast called the AtLast which plugs directly into the output from a dimmer. Very neat.

[pscandrett]

Hi - sorry to revive this thread from 2003 but it seems relevant enough to my question and saves starting another one...

 

An alternative route would be to use architecturals - basically long thin tungsten bulbs. They can be run off standard dimmers and would probably look better than flori's (IMHO).

Our creative types for our bands would like to have (6'?) fluorescent tubes dotted around the stage, vertically, in pink, blue and white. They actually said neon to start with but I suspect fluorescents are easier to work with; we can gel them to get the colour.

 

I'm interested in either switching them on and off remotely or dimming them. The former is easy, power-wise, as we have DMX switch packs - but how does one stop them blinking before coming on? I've never known a tube to light reliably first go each time!

 

Secondly, having them dimmable would be great; I've emailed Specialz about their Atlast unit as per further down the page, but people have mentioned dimmable ballasts from electrical suppliers; are these any good, now we're five years after the original post? Are they pricey? Are they even worth it?

 

I'm intrigued by Tom's reference to 'architecturals' - can anyone give me a more specific name for these please, as they might be an option, too?

 

Finally, can anyone recommend any other solutions? I was pondering LED units, perhaps... Chromastrips look like they might be a way forward, but obviously LED stuff is relatively pricey... but there might be money available to invest if they're multipurpose (eg we could use them in truss etc and at other events we do).

 

Many thanks for any further comments.

 

(We're also trying to make portable pink glowing canes to varying degrees of success, including a Dragoneye LED in the end of a perspex tube, so if anyone's got any ideas about that too it'd be much appreciated!)

[adam2]

Dimmable flourescent ballasts can be obtained from any good electrical wholesaler, but AFAIK they are not DMX I believe that they use 1v/10v signal.

 

As regards the second enquiry of starting flourescent lamps without flickering, any modern electronic ballast will start in about a second without flickering.

It is only the older type ballasts that use a starter that flicker.

[pscandrett]

Dimmable flourescent ballasts can be obtained from any good electrical wholesaler, but AFAIK they are not DMX I believe that they use 1v/10v signal.

Yes, I saw that on the wiki, thanks; however, it does tell me in big bold letters not to use demuxes so I'm not entirely sure how to control it by DMX otherwise! I suppose I'd need some sort of isolator unit.

 

As regards the second enquiry of starting flourescent lamps without flickering, any modern electronic ballast will start in about a second without flickering.

It is only the older type ballasts that use a starter that flicker.

Fair enough, thanks. I've not come across any fluorescent tube without a starter (but then I've had very little contact with them to be honest)!