LED Lamp Modification for Bayonet Style Incandescent lamps (MA-6100)

Great thread!

This type of LED mod will work to replace a DC bulb, like what is in the MA6100 - but - my question is, do all McIntosh units supply DC to the bulbs? The reason I'm asking is I thought (and I could be way off here) that my MA5100 supplied AC to the bulbs, - if this is the case, I assume that this type of mod wouldn't work on the MA5100 without some sort of rectifier?
 
I just measured the voltage on the MQ101 with a cheap radio shack multimeter. It looks like it is just over 6 volts AC which would explain why the LEDs look like they flicker.

Are the lamps on some pieces AC and others DC?
 
I just measured the voltage on the MQ101 with a cheap radio shack multimeter. It looks like it is just over 6 volts AC which would explain why the LEDs look like they flicker.

Are the lamps on some pieces AC and others DC?


I think so. Waiting for someone *brighter* to chime in.
 
Most all early McIntosh was AC to the bulbs, I can't say 'all' so whenever you do something like a lamp change to LED check the schematic first. Units with Bi-Pin lamps can be 6.3, 14, or 28V, check the bulb number to make sure, then verify from the schematic as I have seen a lot of units with the wrong lamps in them.
 
From what I read on the net, LEDs can be used in AC circuits as long as they are set up correctly. All that aside, will LEDs or diodes turning on and off at 60 Hz cause noise in the component? An LED in DC stays on all the time and a normal light bulb is on and resistive in AC. Will replacing a normal bulb with a pulsing diode cause a voltage pulse in the component? If so, then an LED conversion will work on DC powered back light systems. An AC powered back light system may require a clean DC power supply.

I would really like to convert my components over to LEDs to keep the heat from destroying the face plates.
 
From what I read on the net, LEDs can be used in AC circuits as long as they are set up correctly. All that aside, will LEDs or diodes turning on and off at 60 Hz cause noise in the component? An LED in DC stays on all the time and a normal light bulb is on and resistive in AC. Will replacing a normal bulb with a pulsing diode cause a voltage pulse in the component? If so, then an LED conversion will work on DC powered back light systems. An AC powered back light system may require a clean DC power supply.

I would really like to convert my components over to LEDs to keep the heat from destroying the face plates.

The incandescent lamp draws a lot more current in normal operation then the replacement LED . Plus the lamp will not stay full on but fluctuates between zero V to full supply ~V +/- 60 times a second.

I have never had any noise introduced into the circuit by adding LED's to replace lamps.



Barney
 
Back
Top Bottom