f it is the lamp that is making the noise, then it is the filament (which isa coil if fine wire) vibrating due the the pulsing current. This often happens with AC dimmers too. One might night not expect DC to do that, and you note it does not when the dimmer is bypassed, but as I said above, the dimmer is probably using PWM.

f it is the lamp that is making the noise, then it is the filament (which isa coil if fine wire) vibrating due the the pulsing current. This often happens with AC dimmers too. One might night not expect DC to do that, and you note it does not when the dimmer is bypassed, but as I said above, the dimmer is probably using PWM.

Were the original halogens MR16 form factor as well?

I’m guessing the xfmr was specifically designed for a set voltage/current/power.

Consider this:
Two 20W halogens = 40W.
Power=Voltage*Current
20=12*I
I = 1.67 amps through each bulb, 3.33 amps total drawn from the xfmr

Transformers operate on the principle of Power in = Power Out. The xfmr is probably designed to provide 40W, regardless of whatever current draw you put on the transformer.

The LED’s only need 6W from the xfmr. However, the xfmr probably doesn’t care. It’s still spitting out 40W at 3.33A. 0.5A (2*3W/12V) is all the LED’s need. If the xfmr is still trying to provide 40W at 0.5 amps, the output voltage is compensated up to 80V coming from the xfmr.

Most LED bulbs have protection for this in the “engine,” (the regulator/stabilizer as you call it), called over-voltage protection. This is probably whats causing the bulbs/transformer to fail.

The problem is, especially with transformers, is that you must match the load. If the transformer is expecting a specific load and you give it something it can’t handle, it’ll either destroy the load or damage the transformer.

The easiest way to avoid this is to always match the power of the original load to the load you intend to put in. 40W of halogens should be matched with 40W of LED. This is the gimmick with retrofit bulbs like the MR-16. You’re not really saving any energy when you use retrofit bulbs. You just get a longer bulb life and a lot more light from the same power draw.

LED lighting is a niche market. If you can’t figure it out, wait a few months and LED lighting fixtures will decrease as the market is flooded with new product and becomes more competitive. I’d recommend investing in something like that instead of retrofitting.

Were the original halogens MR16 form factor as well?

I’m guessing the xfmr was specifically designed for a set voltage/current/power.

Consider this:
Two 20W halogens = 40W.
Power=Voltage*Current
20=12*I
I = 1.67 amps through each bulb, 3.33 amps total drawn from the xfmr

Transformers operate on the principle of Power in = Power Out. The xfmr is probably designed to provide 40W, regardless of whatever current draw you put on the transformer.

The LED’s only need 6W from the xfmr. However, the xfmr probably doesn’t care. It’s still spitting out 40W at 3.33A. 0.5A (2*3W/12V) is all the LED’s need. If the xfmr is still trying to provide 40W at 0.5 amps, the output voltage is compensated up to 80V coming from the xfmr.

Most LED bulbs have protection for this in the “engine,” (the regulator/stabilizer as you call it), called over-voltage protection. This is probably whats causing the bulbs/transformer to fail.

The problem is, especially with transformers, is that you must match the load. If the transformer is expecting a specific load and you give it something it can’t handle, it’ll either destroy the load or damage the transformer.

The easiest way to avoid this is to always match the power of the original load to the load you intend to put in. 40W of halogens should be matched with 40W of LED. This is the gimmick with retrofit bulbs like the MR-16. You’re not really saving any energy when you use retrofit bulbs. You just get a longer bulb life and a lot more light from the same power draw.

LED lighting is a niche market. If you can’t figure it out, wait a few months and LED lighting fixtures will decrease as the market is flooded with new product and becomes more competitive. I’d recommend investing in something like that instead of retrofitting.

f it is the lamp that is making the noise, then it is the filament (which isa coil if fine wire) vibrating due the the pulsing current. This often happens with AC dimmers too. One might night not expect DC to do that, and you note it does not when the dimmer is bypassed, but as I said above, the dimmer is probably using PWM.

Were the original halogens MR16 form factor as well?

I’m guessing the xfmr was specifically designed for a set voltage/current/power.

Consider this:
Two 20W halogens = 40W.
Power=Voltage*Current
20=12*I
I = 1.67 amps through each bulb, 3.33 amps total drawn from the xfmr

Transformers operate on the principle of Power in = Power Out. The xfmr is probably designed to provide 40W, regardless of whatever current draw you put on the transformer.

The LED’s only need 6W from the xfmr. However, the xfmr probably doesn’t care. It’s still spitting out 40W at 3.33A. 0.5A (2*3W/12V) is all the LED’s need. If the xfmr is still trying to provide 40W at 0.5 amps, the output voltage is compensated up to 80V coming from the xfmr.

Most LED bulbs have protection for this in the “engine,” (the regulator/stabilizer as you call it), called over-voltage protection. This is probably whats causing the bulbs/transformer to fail.

The problem is, especially with transformers, is that you must match the load. If the transformer is expecting a specific load and you give it something it can’t handle, it’ll either destroy the load or damage the transformer.

The easiest way to avoid this is to always match the power of the original load to the load you intend to put in. 40W of halogens should be matched with 40W of LED. This is the gimmick with retrofit bulbs like the MR-16. You’re not really saving any energy when you use retrofit bulbs. You just get a longer bulb life and a lot more light from the same power draw.

LED lighting is a niche market. If you can’t figure it out, wait a few months and LED lighting fixtures will decrease as the market is flooded with new product and becomes more competitive. I’d recommend investing in something like that instead of retrofitting.

If it means the LEDs have a resistor built in, so they operate from 12 volts, then you should be fine, and the transformer should not shut down, as the current would be a low lower than the halogen lamps drew.

So I suspect these are NOT 12 volt LEDs, and they need a series resistor which is missing, so the current is much higher than it should be. Probably means the LEDs are cooked already.

Another possibility is that the 12 volts for the halogens is AC, not DC, and the LEDs require DC.

So you need to look at the specs on the LEDs, and also check the 12 volt supply. I suspect it is AC.

.