pc speaker to sound blaster line-in

[carangil]

I'm starting to play a bunch of games that run the sound blaster for music, but use the pc speaker for effects, and I tend to like to play at night on headphones. Does anyone have any technical info on the voltages that typically come out of a pc speaker connector on a motherboard? I would really like to just hook it up to the line-in of my sound card. I don't want to fry anything by putting too high a signal in through my sound card

 

[Raven]

Most sound blasters have a special connector marked SPEAKER or the like for this, just hook a wire from the speaker output on the mobo to that port and you're good to go.

 

[Chuck(G)]

Well, look at the circuitry. The speaker is switched between about 0.7 and 5.0 v. So, if you need a 1v signal, you could place a voltage divider (and DC blocking capacitor) in place of the speaker. Try 100 and 470 ohms in series, with the 100 ohm end grounded. Take your audo output from the junction.

 

[carangil]

Thanks, I wasn't sure if it always was 5v or what. I'll make a divider, and I'll throw in a trimmer just so I can adjust the volume to something appropriate.

Now that you mention it, I think I have seen speaker inputs on sound cards before. This particular machine (486) I'm runnng Media Vision PAS/Jazz 16, so it has line-in and cd-in, and thats it. I do have a SB16, but that's living in my k6/voodoo machine. (Originally I had the PAS in the k6 machine and SB16 in the 486, was went 'duh, put the better card in the better machine!)

Last time I was at weirdstuff they had a bunch of random 'as-is' isa sound cards; I could probably find a SB16 or SBPro with a speaker input. Though, DIY is more fun, AND I kind of want to keep the PAS.

 

[Anonymous Freak]

Lots of the older sound cards would put the "PC Speaker" input in a different place on the card than the rest of the inputs. Often a physically different plug, too.