Voltage levels and VU meters...

[Chris Crosskey]

Jaroslav wrote...

> 
> Hi, for this application is LM 324 good choice (I not love to use twin
> supply, I say that thing must be able to operate from cheap 12-15V
> adapter). But output res can be true omit, because output of rectifier
> stage has drive diode, which have some resistance too. But I 
> use as R1 (100
> ohm) and cap 10uF, R2 47kohm). But I think that I will change R1 with
> "short wire" and decrease cap. (I really need fast rise 
> time). But if you
> use different design of rectifier, you can need to use R1 - its true.
>

If you read the original post you'll see that I specified a bipolar 15V
supply... it has to run from it and it has to deal with signals generated
from a 15V bipolar too...

> You have true, that VU originally mean Volume Level and has 
> slow rise and
> fall time. Note, that original VU meter has non-linear frequency
> characteristic too. But in digital age the VU meter would be 
> need little
> changed - linear freq. char., ultra fast rise and long fall 
> time. All of
> these is your own options for your own specific design. If 
> you will use my
> component values of this level indicator for digital reverb 
> unit, it will
> good. But for passing signal through analogue vocoder or VCA, 
> it is not
> good.
>

What I need is some sort of average level meter to tell me whether or not
I've pre-amp a signal up to something the modular runs with
internally.....quite frankly I could do it with three LED's and a bunch of
comparators  but it wouldn't look as good....I might well use the design in
some sort of final mixer stage too...a white panel 18" x 9" covered in knobs
and sliders with illuminated circular VU meters....doesn't sound very retro
at all :-))

chrisc