Help with music light circuit

[Cazzo]

Hello

found this circuit a while ago, and im not sure if it actually works, or how it works. i just wanted to make sure before i build it. hopefully someone can just look at the schematic and know if it will work. if not can you be of any help?

Thanks

 

[sheldonstv]

Try this...........

 

[Cazzo]

Thanks Dardy

Will this be able to replace the 3 single LEDs with a MOSFET to run a 12v strip of multiple 5mm LEDs??

---ALSO----- if my power is a 12v car battery instead if the 9v on your schematic will it still work? If not does it need a voltage regulator, which would work?

 

[audioguru]

I don't know why the circuit had the useless opto-coupler and was missing an important input resistor.
Do it like this:

 

[Cazzo]

Thanks audioguru! Sick **** from many sites!! Circuit is mad thanks. These LEDs will beat with the bass beat or treble Aswell??

And where it says audio in, one of the inputs goes there Abd the other goes to where?? Ground?

I want to connect this to my cars amp speaker output that goes to the subwoofer. This won't drain the amp or affect it will it?? The 1k resistor should protect true? Abd if the other speaker cable does go to ground will that blow this circuit in any way or just add it to my car as a common ground.

 

[audioguru]

These LEDs will beat with the bass beat or treble as well??

There is no audio filter so the LEDs will light with any frequency that has a level that exceeds the input threshold.

And where it says audio in, one of the inputs goes there and the other goes to where?? Ground?

Yes, but most car sub-woofers have signals on both terminals of the sub-woofer output (no ground connection) so make the ground connection at the amplifier.

I want to connect this to my cars amp speaker output that goes to the subwoofer. This won't drain the amp or affect it will it??

No.

The 1k resistor should protect true?

No. The maximum allowed negative voltage for the input transistor is only 5V so an additional resistor is needed to make an input attenuator depending on the maximum output of your amplifier.

And if the other speaker cable does go to ground will that blow this circuit in any way or just add it to my car as a common ground.

The output of a car sub-woofer amplifier usually has no ground.

 

[Cazzo]

Yes, but most car sub-woofers have signals on both terminals of the sub-woofer output (no ground connection) so make the ground connection at the amplifier.
.

That's what I was saying, the 2 speaker outputs have signal in each so I can't connect it to the cars ground, I meant if it just goes to the ground on your little circuit so it's isolated from the cars ground? Because I want to run this circuit off the cars battery so I will end up with one speaker output connected to the cars body(ground) I feel it will be bad.

That's why I was thinking you meant connect the other output to the ground only on your circuit, but the circuit is getting its ground power from my cara body ground.

I think I'm confused when you said "so make the ground connection at the amp"

Sorry if it dosent make sense, I'm a little stoned but feel free to ask me to clarify anything. I think I sort of got it across

 

[audioguru]

That's what I was saying, the 2 speaker outputs have signal in each so I can't connect it to the cars ground, I meant if it just goes to the ground on your little circuit so it's isolated from the cars ground? Because I want to run this circuit off the cars battery so I will end up with one speaker output connected to the cars body(ground) I feel it will be bad.

Correct. You NEVER connect the output of a power amplifier to ground.
Pick one wire from the sub-woofer speaker as the input to your circuit.

Your circuit should have its power and ground connections from wires connected at the amplifier. Then currents in the car body from lights and electric motors will not cause interference. The single signal wire from the sub-woofer connects to the input of your circuit.