IGBT vs SCR Dimmers for house lights

[schan]

Do any of you have actual experience comparing IGBT dimmers against SCR dimmers for your house lights in a sanctuary?

The IGBT dimmers are supposed to run a lot cooler and therefore do not require cooling fans, they are supposed to be more energy efficient, most of all lights that are dimmed with IGBT dimmers last longer and run quietly (i.e. not noisy even when dimmed). SCR dimmers on the other hand are just the opposite on all the items mentioned above.

Is the noise difference very noticeable in your installation? How many house lights do you have at your installation? Do you consider the benefits worth the cost premium of IGBT dimmers?

[millamber]

In my experience, IGBT dimming is prone to problems, it doesn't respond to DMX in a timely fashion, and is very "steppy" when dimming. My company has installed hundreds of SCR dimming systems and maybe a half dozen IGBT systems, specifically the ET dimming rack. We stopped selling them because of the myriad of problems we received from the clients that had them installed, from cards failing to noticeable choppyness in the house lights.

I have had better luck with the Smartbars from ETC and the igbt dimmer in the VL 500 and VL1000 but if it were my money, I'd invest it in good quality SCR dimming, such as the Sensor+ line from ETC or the C21 line from Strand. You'll have less headaches in the long run.

[schan]

Millamber, Have you noticed significantly less noise from IGBT dimmers? Do you know whether the Strand A21 line of IGBT dimmers are any good?

[Esoteric]

We have a major performing arts center here that uses A21s and I have not heard any complaints yet.

Mike

[schan]

Chris, What kind of problems did you have with IGBT dimmers?

Mike, Are the A21s that you have IGBT or SCR?

Thanks
Sam

[millamber]

Sam,

Most of the problems we had were with the ET Capio dimmer rack. I've only ever installed 1 a21 rack, so I don't have a good frame of reference about it.

The Capio rack however had all kinds of problems. If one were to call up a dimmer from 0 to full on a console, it would take a good 2 seconds for the light to actually come on. Once the electronics caught up, it would dim as expected, but let it sit for 5 or 10 minutes and you'd see the same thing happen. On occasions it would fade up rather then pop on instantly. I also had several modules go bad, even while under warranty; one actually shorted and burned up the card!

The noise refers to filament noise, the hum you can hear when you dim cheap SCR dimmers. I didn't particularly hear any hum, but with proper SCR dimming and adequate grounding you don't really hear filament noise either. The rack still had a fan on top that was extremely loud. The rack needed to be located well away from the stage or sanctuary so that it wasn't heard by the audience.

Strand dimming is well respected, and apart from the short lived SLD rack, all of their dimming products are rock solid. I'll let you make your own decision, but if you are buying, I would at least speak to someone who has them installed in a space to find out what an owner thinks. Any good dealer will provide you with a list of their previous clients.

[D.R.HADDOCK]

Good quality scr racks should not overheat if mounted correctly.
If they do they are either poor quality or not mounted correctly.
The amount of heat given off is only about 1 watt per 1000w of load per channel.
My racks only get just warm, but I made sure they were mounted in such a way that
they ventilate well.
By the way triacs are just two back to back SCRs in one package.
Most of the older racks are triacs/scr.
My racks are now 20 years old, but they still work well
and are very well made.