LED screw-in replacements dimmable with decent curve??

[jtweigandt]

We have some very conventional industrial appearing fixtures for the auditorium lighting in our theater. Some 100 watt with a glass cover on the lower areas covering the aisles Most of the main fixtures up high are just
open bulb simple white reflector "barn light" and 200 watts.. I need to confirm but I think regular not mogul base. Anybody come across simple replacements with a useable dimming curve.. All the candidates I have tried in the 100 watt
have been pretty miserable failures dimming wise.. dim to about 1/2 then just drop out.. Hard to give up my "crowd control" house to half.. slow fade.. hey folks sit down now.. I really mean it.. yes you sir.. stop fiddling with the walker and git er done, and you gabbing in the aisle.. sit your butt down....

My house lights are actually on a set of 5 mechanical slide dimmers installed in about 2001... We actually have them "tied" together with a notched stick. Yeah.. don't preach.. it's always the last upgrade on the list.

 

[JAC]

We've had pretty good luck with TCP (Technical Consumer Products). They make both dimmable and non-dimmable, so you have to be careful which you're buying, but the dimmables dim pretty well. Obviously, try a few on your dimmers before you invest in a hundred.

 

[Lextech]

When we redid our two venues we found out the solution with retrofits dimming correctly, or at least close enough, was to replace our D20 cards with PhaseAdept cards. Also for home use I had to replace older mechanical dimmers with ones specifically designed for LED. So I think you might consider looking at dimming before you spend lots of time and energy on lamps.

 

[almorton]

Yes, the dimmable LED fixtures intended for standard line dimming tend to work better on trailing edge dimmers, whereas traditional theatrical dimmers are leading edge. Even with the right dimmers, you won't get really smooth dimming down at the low end, they will be be some snap, and it may not be at the same level for each lamp (or even the same each time), leading to what is often called popcorning as the lamps pop on at low level in a random pattern.

 

[RonHebbard]

Yes, the dimmable LED fixtures intended for standard line dimming tend to work better on trailing edge dimmers, whereas traditional theatrical dimmers are leading edge. Even with the right dimmers, you won't get really smooth dimming down at the low end, they will be be some snap, and it may not be at the same level for each lamp (or even the same each time), leading to what is often called popcorning as the lamps pop on at low level in a random pattern.

@almorton DId / do dummy loads help the low end performance?
Toodleoo!
Ron Hebbard

 

[almorton]

Not entirely. They stop the random flashing you sometimes get from the snubber leakage charging up the LEDs, and they can delay the switch on a little so the LEDs don't pop on quite so brightly/suddenly, but we've found that you're on a hiding to nothing trying to get theatre quality dimming out of line dimmed LEDs with theatre dimmers. That's why we've swallowed the pill at our theatre and replaced all of our screw in PAR fittings with proper, dimmable, ETC ArcSystem lighting. Relatively expensive initially, but it will dim properly, the tungsten-halogen PAR lamps are getting like hen's teeth, and those we can get are sub-standard. Our theatre is saying farewell to tungsten fittings; it's a shame in some ways, but that's where we are.

What we did, as an experiment , was swapped out one lamp from a circuit, leaving the other 10 or 11 75W lamps on the dimmer. So there was about a 750W "dummy" load on the circuit with single, dimmable, LED lamp.

Then we did a slow fade up from nothing to full. At around 20% the LED popped on, much brighter than all the others, and stayed like that until the level got to about 50% then it began to increase, topping out at its 100% level at about 80-90% on the dimmer, so the incandescent lights were still getting brighter.

Then we faded out, and got pretty much the same in reverse, very little change in the LED until the rest were down to about 80%, where it dimmed (out of synch with the rest) down to about 15% (it was always brighter than the rest) where it popped off, then the incandescent lamps continued to fade down to zero.

So very unsatisfactory; OK for a gotta have something emergency replacement, but not acceptable for normal use.

 

[almorton]

Really, not worth the trouble.

 

[RickR]

If those slide dimmers are standard wall box type then upgrading them to modern 'universal' LED rated dimmers will improve the curve for minimal cost.

 

[RC4Wireless]

The problem here is that line-voltage LED lamps have built-in electronics to handle the current-limiting for driving LED components. Commercial devices are designed to be (a) lowest possible cost, (b) generate the least possible heat, both while passing worldwide product safety requirements. Quality of dimming is literally an after-thought, not a priority at all. In some cases, if a design sort of dims a bit, and the device doesn't overheat (or otherwise fail ETL/UL testing) they will label it as dimmable.

Dimmers like you find at Home Depot that are specifically rated for LEDs generally just set a much higher level at the bottom of the range. This ensure there's always some power to drive the built-in electronics and will often be higher than that pop-corn pop-on level. So then, when you turn the dimmer on at the lowest level, all the lamps in your living room ceiling come on together, but are probably at somewhere in the range of 30 - 50% brightness.

 

[alich]

I'm not sure if they still work but the 4-Flow blubs that Cree was making a few years back line dim without issue, at least with D20s in a Sensor 2 rack.

 

[wakkoroti]

We have some very conventional industrial appearing fixtures for the auditorium lighting in our theater. Some 100 watt with a glass cover on the lower areas

These are pretty solid.

SORAA

www.soraa.com