McIntosh led lamp replacement help

Hey Norm,

That is a great idea. It will reduce the power consumed.

You want to measure the voltage at the lamps now, and compare to the voltage required by the LED strip as well as the current, and add a resistor as needed to compensate.

Essentially you want a "voltage divider." For instance, if your LED strip requires 5 volts, but your lamps are 12V, you need the resistor to drop 7 V across it at the lamp current.

R = V (to be dropped)  / LED Current

You also need to calculate the power dissipated by the resistor.

W = V (to be dropped) * LED Current

I like to keep a 2x safety margin. So if you need 0.5W, use a 1 W resistor. The higher the power dissipated the more air you need to leave around it to cool it off and prevent heating of nearby components.

Best,


E

I should point out, sometimes the math doesn't work, and you need to use an L pad instead, which adds a second resistor. If you get within a couple of volts however you'll be golden.

Best,

E

Save the trouble and obtain a ready made kit from Audioclassics.com, they have been offering LED retro fits for McIntosh for a number of models. The other part of this modification is the LED changes the blue color of the meter and they include light filters to help keep the same look.