# 'Circuitless' LED sound monitor.



## LEDPunisher (Aug 25, 2014)

I'm the kind of guy that likes to experiment with LEDs. To this effect, I hooked up an LED in series with a speaker through a pocket guitar amp. This is a rather strange effect, you get distortion even when it's clean (I assume the one-way nature cuts this to a half-wave thus making it a constant series of peaks, like a distortion pedal will do with gain amplification) yet with half of the waveform cut off you still hear the original tone (at least to my untrained ears.)

Here's a video: 

Yea, I'm 'drunk.' Forgive me, I'm in a constant state of intoxication due to medicines I must take.


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## Conte (Aug 25, 2014)

Clipping diodes. This trick has been used before.

Marshall added diodes to some tube amps in the 80s to get this effect.

Mind you, Marshall put them in the preamp circuit. 

Not sure if they were the first and only ones to do this, probably not. In the end it's not the best way to generate distortion so nobody does it anymore. 

It was done at an awkward phase when solid state amps sucked, they hadn't designed circuits to push tube circuits hard enough yet, and rock players were demanding more aggressive sounds.

If I recall off the top of my head, the Marshall jubilee 2555 that slash from guns and roses uses was designed that way.


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## Str8stroke (Aug 25, 2014)

cool idea,

You could probably hook the led up to the wires from the speaker, play some loud music, making the speaker vibrate, and the vibration may cause the led to light? I was thinking of trying this with a 15" woofer. 

edit, maybe one with a dual voice coil would produce more?


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## LEDPunisher (Aug 26, 2014)

> You could probably hook the led up to the wires from the speaker,



That's how it's done, actually. The diode is in series with the speaker. I should have done two, one in reverse polarity, so the signal wouldn't be a clipped half waveform and would sound better.


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