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VU meter

Antoni_litz22

Sep 21, 2018
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Can i connect a VU meter in parallel with the speaker? if not, where's the right place to connect a VU?

Ps: It's a TDA2009 typical circuit and there's no preamp.
 

Audioguru

Sep 24, 2016
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The signal voltage across the speaker depends on its impedance and the power supply voltage of the TDA2009, both we do not know.
Also we do not know the input sensitivity of your VU meter, it might be made to show a line level (amplifier input) or a speaker level(amplifier output).
 

Antoni_litz22

Sep 21, 2018
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The signal voltage across the speaker depends on its impedance and the power supply voltage of the TDA2009, both we do not know.
Also we do not know the input sensitivity of your VU meter, it might be made to show a line level (amplifier input) or a speaker level(amplifier output).
15VDC with a 4 ohms speaker.
About the VU meter sensitivity, there's a potentiometer where i can regulate it.
 

Audioguru

Sep 24, 2016
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The TDA2009 has two amplifiers in it but you said you use only one 4 ohm speaker. Are you using the 4 ohm speaker on the "bridge amplifier circuit" shown in the datasheet?

The VU meter probably has one input at 0V but the speaker of the bridge amplifier does not have a speaker wire at 0V. Use the VU meter to measure the AC on only one speaker wire and 0V then multiply the voltage two times.
 

Externet

Aug 24, 2009
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Or,

Spk(+)----------|>|-------------/\/\/\/----------------VUmeter-----------------Spk(-)

Potentiometer will need to be calibrated to read 0 VU at the level of your choice.

analog-electronic-vu-meter-vector-520466.jpg
 
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