In article ,
alan ralph wrote:
At a radio rally, I bought a ALC/AGC module for £5 which seems to be for
audio use. On the supplied data sheet is shows the input and output as
+4dBu. (Unity Gain) With an ALC range of -16 to +14 dBu and headroom
18dB.

Does anyone know what a dBu is ?

It's the unit commonly used in pro audio. 0 dB is 0.775v. Peak level on
this system is +8 dB so near enough 2 volts. But of course in practice has
a headroom of much higher than this - the +8db peak only really applying
to things like analogue recorders and transmitters.

I was thinking of building it into either a headphone amplifier, or
amplified speaker, to use with some of the simple radio receiver kits
which have very little or no AGC function, but I am looking to see what
sort of drive level it needs.

'Normal' domestic equipment line levels - if there really is such a thing
- tend to be about 6 - 10 dB lower.

--
*The only difference between a rut and a grave is the depth.

Dave Plowman London SW
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