Audio signal conversion

[dortbinbir]

Hello,
I'm making a pre-amp that utilizes TDA7318 (yes its old) and an analog VU-meter (with driver board) along with an Arduino Mega as a controller and a Nextion TFT for display and input.

So far so good, however, the TDA7318 audio output is 4.5V whilst my Vu-meter (nakamichi branded) requires a line-level input. Therefore, a conversion is required between them. I'm just ignoring impedance difference (if any) since it's above my poor electronics knowledge.

Appreciate any help.

Thanks

 

[Harald Kapp]

Use a resistive voltage divider. Depending on the curent the VU meter requires, you may also use a trim potentiometer to fine-adjust the VU's display.

 

[dortbinbir]

Thanks

 

[crutschow]

You could also use just a trimpot with the resistive element connected between the TDA7318 output and ground, and the wiper connected to the VU meter input.
A 5k to 10kΩ trimpot should likely work.

 

[danadak]

Does the VU meter board require an offset range V span to accommodate it ?

If so this will help, attached.


Regards, Dana.

 

[AnalogKid]

Can you post any information or links to the VU meter and its board?

ak

 

[aleckpellitier1]

A VU meter, also known as a volume unit meter, is a device used to measure the audio signal's level in decibels (dB). It is commonly used in audio recording and broadcasting equipment to indicate the audio signal's level and prevent it from clipping or distorting.

Here are some links to websites where you can find more information and purchase VU meter boards:

• Adafruit: https://www.adafruit.com/category/113
• Amazon: https://www.amazon.com/VU-Meter-Module/s?k=VU+Meter+Module

 

[AnalogKid]

A VU meter

If that was a response to my question, you misunderstood. I have some familiarity with what a VU meter is (and a copy of Howard Chinn's book).

My question was for the TS, to see exactly what he is working with. There are many things out there that are called a VU meter, but do not meet most of the requirements for one. His meter has a "driver board", and that raises a bunch of questions.

Also, the adafruit link is to a different product line.

ak

https://www.aes.org/aeshc/pdf/how.the.aes.began/chinn_measurement-of-audio-volume.pdf

https://www.aes.org/aeshc/pdf/chinn_a-new-svi.pdf