Single LED VU-Meter-like indicator

felix42 · 1st August 2006, 09:24 AM

Hi everybody,

I am looking for a circuit that modulates the brightness of a single LED somehow proportional to the signal level (preferably taken from the preamp output).. It doesn't have to be accurate at all, this is just for eye candy.
I think they use this type of display a lot on bass amps and i think it must be similar to the clipping indicator circuits you see around here.

Can somebody point me in any direction here?

Thanks in advance!

Frank Berry · 1st August 2006, 10:46 AM

felix42,

You might try something like this. It's simple.
Trim the value of the feedback resistor to obtain enough gain to drive the LED.
Use a bi-polar power supply. + and - 15 volts will be good.

Frank

destroyer X · 1st August 2006, 08:09 PM

I think this will fit your need.

And the best way is to do it in a experimental way...to see the ligth modulation if fits your needs.

regards,

Carlos

felix42 · 2nd August 2006, 08:59 AM

Looks good, i'm going to try it out today.

Thanks for your help!

felix

destroyer X · 2nd August 2006, 09:08 AM

http://www.diyaudio.com/forums/showt...046#post716046

aufwiederlehsen

Karl

cpemma · 2nd August 2006, 12:53 PM

Here's one that appeared in a Maplin magazine about 20 years ago. I've made single level versions to indicate danger to some 15W outdoor speakers I have. Runs off the speaker power, so audiophreaks beware.

destroyer X · 2nd August 2006, 12:56 PM

But it is beeing used inside many good brand speaker around the world, including now a days studio monitors.

regards,

Carlos

cpemma · 2nd August 2006, 01:01 PM

Stripboarded unit

cpemma · 2nd August 2006, 01:44 PM

There's also a LB1443N "vu-meter" IC, 5 LEDs and simpler/cheaper than LM3915/6 circuits. The NAD3020 schematic linked nearby shows how they combine a signal from both speaker channels.

1st August 2006, 09:24 AM	#1
felix42 diyAudio Member Join Date: May 2006	Single LED VU-Meter-like indicator Hi everybody, I am looking for a circuit that modulates the brightness of a single LED somehow proportional to the signal level (preferably taken from the preamp output).. It doesn't have to be accurate at all, this is just for eye candy. I think they use this type of display a lot on bass amps and i think it must be similar to the clipping indicator circuits you see around here. Can somebody point me in any direction here? Thanks in advance!

1st August 2006, 08:09 PM	#3
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	I think that a limiting resistor, a zener diode and one led I think this will fit your need. And the best way is to do it in a experimental way...to see the ligth modulation if fits your needs. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!.. when not work first time, then becomes a nice challenge...and we usually overcome the trouble... and we feel very well to be mastering the machine.

2nd August 2006, 09:08 AM	#5
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	Hi Felix, this is a thread that may be intersting to you http://www.diyaudio.com/forums/showt...046#post716046 aufwiederlehsen Karl __________________ Try to build an amplifier folks ... it is pure adrenaline!.. when not work first time, then becomes a nice challenge...and we usually overcome the trouble... and we feel very well to be mastering the machine.

2nd August 2006, 12:56 PM	#7
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	Cpemma, this circuit works fine...very old really But it is beeing used inside many good brand speaker around the world, including now a days studio monitors. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!.. when not work first time, then becomes a nice challenge...and we usually overcome the trouble... and we feel very well to be mastering the machine.

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2nd August 2006, 08:59 AM	#4
felix42 diyAudio Member Join Date: May 2006	Looks good, i'm going to try it out today. Thanks for your help! felix

2nd August 2006, 01:44 PM	#9
cpemma diyAudio Member Join Date: Jul 2003 Location: S Yorkshire OK	There's also a LB1443N "vu-meter" IC, 5 LEDs and simpler/cheaper than LM3915/6 circuits. The NAD3020 schematic linked nearby shows how they combine a signal from both speaker channels.

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