[linux-audio-user] Speaker Jack

[Remco Poelstra]

On 2002.10.17 21:18 linuxmedia4 at netscape.net wrote:
> Greetings,
> 
> I just bought a new system. It has integrated sound on the Mother
> Board. There is a jack marked "spk" (obviously the speaker jack). But
> the manual refers to that jack as "line-out" I was always under the
> impression (just an assumption) that "line-out" and the speaker jack
> put out completly different voltage levels (and we know how dangerous
> it could be to plug things into the wrong voltage levels).
> 
> Are the standard speaker jacks indeed "line level"?
> 
> There's several possiblities that I can think of:
> 
> 1. The standard "speaker out" jack complies to the "line level" standard
> 
> 2. Since it's a costom made computer, the jack is incorrectly marked
> and its actually a line out jack. (after all, the VGA port is marked
> as "COM2")
> 
> 3. Since the manual covers several versions of their Mother
> board, it's actually a different interface that it's referring to (I've
> run into this with the manual before).
> 
> I'm actually hoping to find out that the speaker out jack complies to
> the line level standard. This way I can use the speaker out for line
> level devices.

Why don't you measure it with a voltage-meter? It should be around 1.5-2 V 
for a line out device. Most of the time it's a speaker out connector that 
just delivers line voltage. Lots of the small speakers are 4Ohm, which 
means that with the line level voltage you get 1W rms power. That's enough 
for most computer bleeps.

Remco Poelstra