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Headphone to RCA

I'm looking to interface the headphone jack on my laptop with an RCA jack on my TV. I already have a cable that goes from 1/8th inch stereo to stereo RCA. The problem is, the volume is terribly low and loud noises (such as explosions during a movie) cause the output to saturate and the volume drops even more. So I figured I could build a simple op-amp circuit. I've been looking everywhere for the electrical characteristics of the headphone jack and the RCA jack but I can't find anything! Apple's website lists the characteristics of their headphone jack as having a peak output of 4.5Vp-p with a 10 ohm source impedance. Of course, I have a Compaq laptop, but I figured mine is probably about the same, at least with respect to the peak output voltage (which is all that really matters with an op-amp since 10 ohms is nothing). Also mentioned that headphones have an impedance of 32 ohms so I thought I might make the input impendance of my little amp 32 ohms. But I can't find anything about the RCA jack. In particular, it'd be nice to know what the max voltage is that it expects. I wouldn't want my amp to drive it too high. Any information or other insight would be great!

Reply to
trogadoror
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How is the RCA jack on your TV labelled? Ext audio? Line level? RCA line level outputs between hi-fi seperates are usually around 200mV which doesn't make sense if your laptop delivers volts.

Reply to
Andrew Holme

trog posted:

--
You need to put a (approximately) 32 Ohm resistor to ground to terminate each
laptop output. Capacitively couple the stero pair of your (32 Ohm terminated)
laptop, to the TV input.   This will eliminate the blasting and there may be
enough signal voltage to give you a decent level.  If not, try the OP amp
again, with 100K Ohms to the - inputs and 1MegOhms in the FB path.

Don



Don
Reply to
Dbowey

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