Analog VU meter in power amplifier

[multisync]

not knowing the output level of your line source or headphone out, however from the example I would try a 1K to 2K resistor for R1 R2 and see what happens.

 

[giaspyr]

hello, after I read datasheet, and look installation recommendation on a*iexpress that unit was designed to connect in output of amplifier (speaker out) in example from datasheet, when connected to 100 watt RMS output amplifier R1 value is 27k ohm. I've already make this vu, but I need to connect itn after line out / headphone out from soundcard or recorder (zoom h1). so how to calculate R1 to match input source?

I've used a similar TA7318P VU meters driver to a preamp, after some trial and error swaps at the value of R1/R2 ended up using 2.2K resistors.

 

[ayokzone]

not knowing the output level of your line source or headphone out, however from the example I would try a 1K to 2K resistor for R1 R2 and see what happens.

I've used a similar TA7318P VU meters driver to a preamp, after some trial and error swaps at the value of R1/R2 ended up using 2.2K resistors.

Thank you for your reply, I used 2 devices

the first is Zoom H1 the spec said the headphone output is 20 mV @ 32 ohm, so after calculate with data sheet formula I found around 800 ohm for R1 then I use 1K ohm for that, so far it was okay.

but another devices that I use is Behringer UMC 1820 it says +16 dbu for line output, I didn't know how to determine R value from dbu data, any idea?

 

[multisync]

http://www.sengpielaudio.com/calculator-db-volt.htm

 

[MAAC0]

Use a trim-pot and adjust

 

[ayokzone]

is there anyone ever try this schematic, I try make one with breadboard but it's very little movement, but with TA7318P it's worked. But I try to find another circuit with minimal part, because the IC TA7318P is a bit expensive and rare here.

here's the link to original website A simple passive logarithmic VU-meter

and also I found another schematic that work and also cheap, but I'm curious does it affect sound quality of the output of amplifier?

my amplifier si around 20-50 watt​

here's the schematic

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