DMX dimmer for mains led's

[spotblaster]

I have been asked to investigate changing the bayonet cap

tungsten candle lamps in our two house light chandeliers for led equivalents.

 

The chandeliers are currently fed from a single channel DMX dimmer under control of the lighting desk.

 

I have seen "dimmable" mains led candle lamps but am guessing I will need a different DMX dimmer.

 

Any advice and reccomendations would be gratefully received.

 

Many Thanks

 

 

David Ashton.

Sutton Arts Theatre

[Edward- Z88]

Hi David,

 

I believe I replied to your email to Zero 88 Enquiries about this.

If there is any further Zero 88-specific information you need, just let me know.

 

Edward

[timsabre]

If you need a smooth fade up from black, this is not possible with mains dimmable lamps on any type of dimmer. You will always get a snap to 20-30% brightness at the bottom as the lamp powers up from off. You might get snap to black on the way down too.

 

If this is acceptable, the answer to your dimmer question is you need a trailing edge (mosfet) dimmer or the lamps will flicker and strobe as you dim them. The only place I've found DMX trailing edge is as din rail modules from chinese suppliers - maybe others know of alternatives.

 

On some lamps you can sometimes dim to a low level such that the lamp goes out but the driver stays powered, if you can manage this then you can fade in without a snap. It's highly dependent on the particular lamps you use though.

Edited October 11, 2019 by timsabre

[Bryson]

ETC make PhaseAdept: https://www.etcconnect.com/PhaseAdept/ Not sure if it's available in 230V / CE though.

 

They also make EELV modules which may be a better fit: https://www.etcconnect.com/workarea/DownloadAsset.aspx?id=10737460652 Again, not sure if they're a 230V product.

[Don Allen]

There is a 4 channel trailing edge dimmer available in the UK but I have no idea of pricing. Seems to be designed with cinemas as it has panic switch mode.

[musht]

Best mains dimming lamp have seen are the Philps Warm Glow series

 

https://www.toolstation.com/philips-led-warm-glow-dimmable-candle-lamp/p55646

 

dim and start very close to zero.

[J Pearce]

I’ve had 3 of my regular venues try to update their houselights in this fashion. On every occasion the result has been unworkable and we’ve had to rig production lights to use as houselights.

 

Venue 1 eventually splashed the cash on a very nice GDS install, venue 2 went back to halogen lamps, venue 3 only discovered the issue this week and are now back to the drawing board as halogen lamps for their fittings are now discontinued.

[sandall]

My local theatre has an old Strand Environ dimmer in the main house (now all-LED), which was quite happy with a mixture of halogen & LED MR16s until all the halogens had been replaced; the studio theatre has an Anytronics & is all-LED. Both systems work perfectly, but only with Philips lamps.

[Simon Lewis]

Artistic Licence had an interesting LED dimmer out at PLASA.... it won an award too...

 

[spotblaster]

Good to hear from you Simon. It's been a while!

 

These Artistic License units look as if they might be suitable (or "least worse") in our situation in combination with the Philips lamps reccomended above. It's what happens at the bottom end that is important for us.

 

I am looking to replicate that lovely gentle fade up from black that you get with tungsten if at all possible.

 

Had anyone tried these dimmers in anger?

 

Many Thanks

[Tomo]

I am looking to replicate that lovely gentle fade up from black that you get with tungsten if at all possible.

You won't get that from a mains dimmable retrofit LED lamp, as none of the 2-wire dimmable mains LED retrofit lamps are physically capable of dimming to and from black.

The lamps will always snap on and snap off, and most will "popcorn" as well, as manufacturing tolerances (and degradation over time) mean each lamp switches on (and off) at slightly different times and levels.

 

Reverse-phase/trailing-edge (mosfet/IGBT) is usually better than forward-phase (SCR/Triac), but never anywhere near as good as tungsten.

 

The only way to get a good bottom end in LED is to use 'proper' LED drivers that take hot power and a separate dimming control signal.

The 'simplest' is to use a load of 'standard' LED Pars, but that's obviously not feasible for many chandeliers.

 

There are a few retrofit lamps that take hot power and a control signal via radio or the existing load wiring, those are the ones to look for.

 

For example, the ETC ArcSystem lamps are wonderful, especially the fade-to-warm version.

As you've currently got a dimmer installation should be pretty easy, you just remove the existing dimmer and replace it with the ArcSystem driver box, and replace the lamps with the ArcSystem lamps.

 

The driver is DMX controlled and provides the 24VDC and control signal to the lamps - 6 to 30 lamps per circuit, depending on model.

[spotblaster]

Many thanks for all your replies.

 

I have bought one of the reccomended Philips lamps and in parallel with the existing tungsten load it dims fairly smoothly on the fairly modern Strand single channel DMX dimmer. I would guess it snaps in at about 5% which is way below anything else I have tried.

 

The Artistic License "Sundial" dimmer sounds very interesting and in time I may get a demo.

 

I haven't researched the ETC Arcsystem yet but it looks as if it would suit us - particularly if existing wiring can be used and hopefully the bayonet lampholders.

 

Thanks again

 

 

David Ashton.

[WayneHowell]

Hi,

 

 

In this thread, our dimmer sunDial was mentioned. We've recently updated the firmware so you can create a dimmer curve to exactly match the led replacement bulb and then upload it. We're also creating a database of dimmer curves for common bulbs (see link below).

 

https://artisticlice...t/sundial-quad/

 

Thanks

 

Wayne.