Audio in

[webster]

I would to be able to connect the headphone jack output to the audio line in on a VCR.
What impedance and voltage matching problems should I worry about?

[ezpcb]

impendence of headphone output should be low enough to drive the input. the voltage should be limited in 800mVp-p, as I remember.<p>mike

[haklesup]

A headphone jack will have a volume control associated with it. Make a test recording at moderately low volume to start and adjust up or down as required to get good sound reproduction.<p>If you are too low the recording will need to be played at high volume to be heard and will likly contain hiss. If set too low, the recording will be clipped and the sound will be raspy and loud.

[jollyrgr]

Don't worry too much about impedance mismatch. The main reason you want impedance matching is for maximum power transfer. In an RF antenna system you are real concerned about matching the impedance to the transmitter because of SWR. But for audio, while it would be nice, it is not a real concern. With the headphone out you have the extra gain to overcome any loss you might have because of the mismatch. I have connected personal stereos headphone out to everything from public address systems, VCRs, home stereos, and even broadcast boards.