12V Led Strip

[Rockwell666]

am I missing something... buddy wants 12v led strip in his tube amp. I was planning to just use the last string of B+ high voltage. need approx. 200v drop @ 25ma = 8K resistor @ 5W. I told him the leds will stay on until the cap is fully discharged but this is the quick n dirty method.... the heaters are already rectified and ran in series (stupid peavey valveking)....

[Colossal]

am I missing something... buddy wants 12v led strip in his tube amp. I was planning to just use the last string of B+ high voltage. need approx. 200v drop @ 25ma = 8K resistor @ 5W. I told him the leds will stay on until the cap is fully discharged but this is the quick n dirty method.... the heaters are already rectified and ran in series (stupid peavey valveking)....

Hey Rockwell,

Martin Manning had a cool idea a while back for a quick and dirty AC to DC trick to light some LEDS. You can come right off the 120VAC primary side of your transformer, just after the mains switch. You just need a diode in the reverse direction of the LED string and resistor to dump voltage. Do the same math. I powered a string of 2V LEDs with 12k and a diode. Worked great. Might be easier in that amp you are working on. Food for thought.

[Rockwell666]

I looked up the specs on the 12" strip of 5050 SMD Leds.. 12V @ 0.25A. Boy that's a lot more juice then I was bargaining for. 122v -12v = 110v drop @ 0.25A = 440 ohms @ 27.5W!!

[Colossal]

I looked up the specs on the 12" strip of 5050 SMD Leds.. 12V @ 0.25A. Boy that's a lot more juice then I was bargaining for. 122v -12v = 110v drop @ 0.25A = 440 ohms @ 27.5W!!

Yeah, I did it with something like six or eight LEDs, not 0.25A worth.

[martin manning]

Got a link to this LED strip you are considering?

[roberto]

Usually 5050 leds need 250mW each diode, then they comes in different led per meter versions.
The most common is 60 led per meter, so 15 watts per meter, so approximately 5W in your 12" strip.
That means 12V and approximately 450 mA

Install a dedicated power supply for them.
You will avoid overloading the PT and also their switching noise.

[xtian]

All these modern LED strips (your 5050, and my WS2812B) state consumption at maximum current draw (about 20mA each LED element, RGB, so 60mA per LED). But that's MAX power. They look great scaled down to lower voltages/current. Just breadboard it on your desk, measuring current as you go, and you can choose a brightness level that doesn't draw too much power.

Another way to look at it: If I was to put a strip of WS2812B LEDs inside my head cab and let it run at its full 20-watt, all ON mode, that's equivalent to a 100 watt incandescent light bulb. That is, VERY BRIGHT for a head cab. Not mood lighting. More like light house lighting to keep the ships away from shore!

[Rockwell666]

Usually 5050 leds need 250mW each diode, then they comes in different led per meter versions.
The most common is 60 led per meter, so 15 watts per meter, so approximately 5W in your 12" strip.
That means 12V and approximately 450 mA

Install a dedicated power supply for them.
You will avoid overloading the PT and also their switching noise.

I tried loading it with only 50ma on the b+ supply and is sagged the voltage down on the B+, the lights were bright enough tho. I think the stupid cheap peavey transformers are barely rated for their application. A sep power supply will be ordered I don't want to install it on the AC side for safety sake.

[bal704]

Why not just put in a Meanwell 12VDC supply?

[Rockwell666]

Why not just put in a Meanwell 12VDC supply?

that's the plan. I had ordered a cheap ebay one and it worked for 5 mins before blowing, so I was trying to run it without a PS. those LED strips def require its own 1A supply.

[bal704]

I always buy mine here:

www,jameco.com

[Rockwell666]

I always buy mine here:

www,jameco.com

oh man those mean wells are perfect! ordered 3!