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Designing LED circuit

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An emitter-follower has no voltage gain, no amplification of voltage levels. But it has current gain because its input current is low when its output current is fairly high.

We do not know if your amplifier and crossover network are able to drive many LEDs so the transistors are used to reduce the current required by the LEDs.

Your 2N5551 NPN transistors have a high voltage rating but a low current gain. Their current gain is poor when the current is only 70mA or more.
But a 2N4401 NPN transistor has high current gain when the current is 400mA or less.

A 2N3906 PNP transistor has a low current gain when its current is 50mA or more and its max allowed current is only 200mA.
But a 2N4403 PNP transistor has high current gain when the current is 300mA or less.
 
That makes a lot of sense. Now that I am seeing so many flaws in my design, is there a cheap way that you would suggest I change my project to get the same results (RGB LEDs driven by audio)? I would prefer to spend as little money as possible on this.
 
An opamp can provide any amount of voltage amplification that you need. It can drive a darlington power transistor that has a very high current gain.
Many LEDs can be driven, but each color in the RGB LED needs its own current-limiting resistor.
You can fiddle with a level control or design an automatic volume control.
 
To be honest, even though I have tried reading up on them, I don't properly understand op-amps.
 
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The cheapest option overall might be to abandon your common-anode (or common-cathode) LEDs and use individual R LEDs, G LEDs, B LEDs. Then you can, say, connect several R LEDs in series with 1 resistor as a string, and drive several parallel strings with one transistor. Likewise the G and the B.
 
Well, my idea had more been to have the red and blue light mix with the music, as opposed to having separate colors. If I used individual LEDs, I would need something to diffuse the colors together, which would be much more difficult to do in the speaker box.
 
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