How many LEDs rated at 5V can I use on a 6 Watt Radio Amp?

I there, I have a 6 watt radio amp that if I used the Voltmeter correctly is only really using 1.3 watts at it's highest volume on the busiest song.  I want to add LED lights to the dial and I'm wondering how many can I use?  I purchased LED lights rated to a max of 6V and the engineer told me that they can be used for a 5V power supply.  I would like to use as many as I can in series and will like to learn how one comes up with that number.  Thanks

sort by: active | newest | oldest
javierdiaz4 (author) 3 years ago

Hi there iceng, I'm new to all of this. the LEDs already have resistors. My question I guess was really trying to figure out if I would have any issues powering these LEDs and if safety is a concern in conjuction with the 6w amp which from what I have measured is at 1.3watts at the moment and I may make some changes to make it go up to 4.5watts.

If you know what the voltage supply [ not watts ] of the radio amplifier then I can help.....

Here is a table ;

A 12v supply => use two leds in series

A 15v supply => use three leds in series

A 20v supply => use four leds in series

javierdiaz4 (author)  iceng3 years ago

iceng, since It seems I'm limited to keeping one light, which is what I already have. Do you have any suggestions or ideas as how I can accomplish wiring up this 5v amp that generates up to 4.5 watts of power to speakers and that will allow me to power up a 6.3volt lightbulb that is already on the radio. What would I need? Thanksa million

javierdiaz4 (author)  iceng3 years ago

Ha, I guess I'll use one and no in series. It's a 5v supply radio powered by an apple usb adapter and a micro usb cord.

iceng3 years ago

You need to know the real LED voltage and LED design current, say white LED which needs 3.6v @ 20ma.

Then go to and plug in

the 6 volt supply

the 3.6 volt led forward voltage

the 20 ma design current

and a 4 led array

click the wiring diagram