This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.

While refurbishing an ageing audio mixer, I decided that the level meters needed special attention. Their rather horrible 100 µA edgewise movements had VU-type scales, the drive electronics being just ...

Given its appearance in one form or another in all but the cheapest audio gear produced in the last 70 years or so, you’d be forgiven for thinking that the ubiquitous VU meter is just one of those ...

One of the coolest things any sound system can have is some kind of musical visualization. Thumping level meters that pump with the volume are a great example, and were particularly popular in the ...