Mains Halogen Dimmer Buzz

9 May 2009
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United Kingdom
A quick search tells me this topic this has been done a thousand times, but I can't find a specific answer to my question, so here goes...

4 x 50W GU10 mains halogens (brand new light fitting) on a cheap Marbo dimmer... dimmer buzzes like hell unless lights on full.

Fair enough, cheap dimmer. So I go out and get a (relatively) expensive and higher rated (500W) MK "intelligent" dimmer. It's worse - it buzzes loudly all the time regardless of how high/low it is set. What gives?

The MK is one of the push on/off type with a soft start(?) circuit. As in, when it's already on full and you push the switch the lights come on gradually.

Could the cheapo bulbs that came with the fitting be causing it? The buzzing is definitely not coming from the bulbs themselves - they are completely silent - but the dimmer came with a warning about using only high quality bulbs. Thing is, I don't wanna go and shell out for decent bulbs and be no further forward.

All info/advice appreciated.
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The way a quartz halogen lamp works is the envelope is so hot the tungsten which leaves the element can't deposit itself onto the quartz so it has to return to the element after some time the element thickness will become less uniform and will become too thin in one part and blow.

So for them to work correct and have reasonable life they should not be dimmed. There are dimmers that will work but they greatly reduce lamp life and are not recommended.

There are Dimmable Energy Saving CFL GU10 Light Bulb but at around £12 - £15 each made by Magaman
these do not require dimming switches but are longer than standard GU10 bulbs but with all tungsten bulbs being phased out to fit any units which will not take energy saving bulbs would seem foolish.

The problem you have is the element is a coil of wire and the natural frequency of the coil in the lamp is reacting with the electronics of the dimmer and changing bulb makes will likely help. Nothing to do with dear and cheap just chance the two units don't match.
Thanks for your quick and detailed reply ericmark. A plain old switch it is then! TBH we were likely to dim the lights only on the odd occasion so it's no great loss.

Knew about the phase-out, but for some odd reason I hadn't thought it would include tungsten-halogen lights.
Because the quartz halogen is a spot lamp it is going to live a little longer than the common tungsten bulb. But not sure on date.

I wanted to get new lamps and was shocked on how hard it was to get lamps able to take energy saving luminaires. Many when they are fitted have the bulb sticking outside the shade.

There is a great debate over extra low voltage (12v) and low voltage (230v) lamps as using quartz halogen the extra low voltage has some advantages but as you move away from the tungsten bulb these advantages disappear and since the low voltage types can use cold cathode discharge lamps the 230v system then has the advantage.
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I wanted to get new lamps and was shocked on how hard it was to get lamps able to take energy saving luminaires. Many when they are fitted have the bulb sticking outside the shade.

The only ones I have really seen so far that take the energy savers are some 4-way fittings I got from Lidl for the kitchen (v.good for the price - came with ES bulbs for £15!). As you say the majority of efforts are still designed for the shallow halogens (and way overpriced at that).

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