antique lights

[david.elsbury]

You could modify the fixtutes to take a more modern bulb. Depending on the layout of the fixture this might not be very hard. Just bolt a new 1kw base in and then you can use a modern bulb with no sing.

FFS please read the topic above... the OP is wanting to use the original lamps in the fixtures as it is being filmed!

 

 

run at 100% with some diffusion over the lights to bring them down a bit. Unfortunately this loses the aesthetic of the 40%. these lights are being used purely for their aesthetic quality not for their light producing ability. because they are 2800k at the 40% they give a nice warm glow

 

put in 300w lamps and run at full. again, this loses the nice glow as they just throw white at 100% (understandably as this is what they are designed to do)

 

 

unfortunatly, with the 300w with colour correction, although it gives the right colour, it loses some of the aesthetic, it becomes very obvious that there is something over the light rather than it being completely open to the bulb and since there will be a full camera rig in we can't rely on the distance of the audience to hide this.

[Tomo]

I suspect the bottom line is I'm not going to fully get rid of the noise without changing the fittings and lamps so something that gets rid of most of it will be great

Surprisingly enough, the ETC/IES Sinewave really does remove almost all the noise.

 

I've done several demos with parcans and more recently with 5kW TV fresnels, and it is rather stunning and not a little disturbing!

 

I always expect the classic "TING!-buzzzzzz" of a CP6x starting up and slowly fading to 100% yet with the sinewave they really are silent, at least to the limits of my hearing when standing a couple of feet away.

 

Unfortunately the PLASA 2006 demo wasn't that great - too much ambient noise from all the other stands!

[dbuckley]

Surprisingly enough, the ETC/IES Sinewave really does remove almost all the noise.

Surprising only if you're young :)

 

Olduns remember resistance dimmers and transformer dimmers, and they didn't make lamps sing at all. Singing lamps is a feature of SCR dimmers, from the sixties on. Well, Ok, there were some thyratron dimmers a bit before the SCR revolution, but I don't think they were widely used.

 

IGBT dimmers can also approach zero lamp and dimmer noise. The reason chokes reduce (but not in practice eliminate) lamp noise is that they limit the rate of rise of current as the SCR switches on part way through the mains waveform. IGBT dimmers are usually trailing edge dimmers, and thus the rise of the current is as normal, but the current is cut off part-way through the half-cycle. The rate of cut-off is controllable, so enabling rate of change of current control that is superior to chokes but without the weight or size. And they don't need fuses. 'Course, all this stuff is still under patent protection, but IGBT dimmers will be commonplace one day.

 

I still use a variac to dim orchestra lights, as it doesn't make any dimmer noise at all, mechanical or electrical, and in the pit environment, the last thing you need is added noise.

[Jivemaster]

Sine wave dimming is the modern way to solve filament sing (which comes from triac dimmers really!)

 

Resistance dimming is the old way (think 2Kw rheostat) but some were wound on asbestos :) and you had to have the correct dimmer for the load rating -a 1K dimmer wouldnt dim a 100w lamp!

 

A series split Y lead would probably do a fixed intensity dimming for pairs of lamps to about half and would be cheap perhaps DIY according to your company's competences. If you need individual on/off control then arrange a 1Kw electric fire element in series with each lamp, done safely please!

 

A continuously rated building site transformer per lamp would also give you a fixed half (ish ) power option.

[Tomo]

IGBT dimmers will be commonplace one day.

That won't happen - there are several fundamental limitations of reverse-phase IGBT (chokeless) dimming that I won't go into, but suffice it to say that Sinewave kicks reverse-phase IGBT dimming's backside, at a very similar cost.

I still use a variac to dim orchestra lights, as it doesn't make any dimmer noise at all, mechanical or electrical, and in the pit environment, the last thing you need is added noise.

Yup - Variacs are great things! The only real disadvantage of Variacs is the difficulty of remote control, and the limited flash rate caused by the physical electrical contacts - you simply can't spin the contacts very fast without causing excessive wear.

A good Sinewave dimmer has all the advantages of Variacs, with the added bonus of DMX control and the ability to rapidly flash the lamp.

 

The real reason for the prevalence of SCR dimming is that until very recently, SCRs were the only silicon with sufficient power and voltage handling capacity for theatrical use.

Theatres accepted the 'lamp buzz' that didn't exist previously due to the ease of remote control, and the reduced physical size of the dimmers which combined to mean that many more channels of dimming were possible - which allowed effects that could only have been dreamed of before!

[dbuckley]

IGBT dimmers will be commonplace one day.

That won't happen - there are several fundamental limitations of reverse-phase IGBT (chokeless) dimming that I won't go into, but suffice it to say that Sinewave kicks reverse-phase IGBT dimming's backside, at a very similar cost.

If that turns out to be the case, then yep, sinewave every time. But for either technology to be widely adopted, it's got to be cost competitive with SCRs throughout the value range, from Showtec to Avo.

[Tomo]

But for either technology to be widely adopted, it's got to be cost competitive with SCRs throughout the value range, from Showtec to Avo.

You are quite right about that - and I highly doubt that will happen any time soon.

Sinewave dimming hardware is fundamentally more expensive than SCR - there's more silicon and it's more expensive silicon as well, even if you ignore the cost of the R&D (which is considerable).

 

On the other hand, the cost of the silicon will come down over time, and the R&D will eventually be recovered.

So prices will come down - but they will never equal an SCR dimmer.

 

There can be savings made due to lower harmonic currents (=cheaper electric bills) and longer lamp life, but I don't know whether those will be sufficient for Sinewave to be cheaper than SCR in the long run...

 

We shall all watch and learn, some of us with more interest than others!

[Nicktaylor]

I know the bulbs you are talking about. I have some I use to dress sets once in a while. I must say I was not aware of a loud noise from them, though it was a play I was using them for. They make a great dressing lamp as a pendent running at about 25%

 

The control was through Zero 88 Betapacks

[enbee]

Hi everyone, sorry to resurect an almost dead post but I just wanted to thank you for all your help on this one. We've just released the event recording and its worked ok. We went for the etc sinewave dimmers and that sorted it to within acceptable levels. All the help is much appreciatted