[sdiy] Analog VU Meter/Simple Attenuator Module

[m.bareille at free.fr]

Selon Scott Juskiw <scott at tellun.com>:

> >What precision do you want ? The TLN-904 is built on a pair of
> >LM3914. It is faster than a galvanometer but only precise to
> >+/-0.5 V
> >
> >   http://tellun.com/motm/diy/tln904/TLN-904.html
>
> Actually, if you set it to PEAK mode you can use the front panel pot
> to get less than 0.5V per LED (e.g. 0.05V per LED). This is not a
> precision measurement, but I have found it handy enough to gauge the
> levels coming from -10db or +4db equipment.

For a more accurate ( 0.5dB steps with a 40leds ladder ) and a 40dB range (-20dB
up to +20dB if calibrated on 0dB )  here is another possible schematic :

http://m.bareille.free.fr/vu-in13/vumeter_in13.htm

You are not obliged to use a 'plasma' tube with it... I think many other RMS
detectors can replace the relatively hard to find THAT2252. It is not
the same cost and complexity than one or two LM3914/15/16...

[OT]The Plasma VU-meter 'final edition' will be online very soon :)
The circuit has been upgraded and integrate now a transformless +150V psu for
the IN13 tube. So the entire circuit is now powered with only +/-15Vdc (or
+/-12Vdc) making it compatible with most of  modular PSUs ...

Cheers,

Marc B.