Electronics

dave · Guest

The TDA7052 1W audio amp chip has two output pins that connect directly to the
speaker. The circuit text say "Do not ground either speaker terminal". I'd like
to connect the output though to a PC soundcard line-in, which is single ended.
Is therean an easy way to do this? I don't want to use a transformer (as I don't
have one!). Can I do this with some RC network/series capacitors?
thanks

Guest

You don't need a transformer, just a small capacitor (1 to 10 uF would
be OK) and resistor around 10K ohms (up to 100K would be OK) preferably
the same values for both channels. Use output 1 only to the '+'
terminal of one of the caps. Other end of the cap is the output.
Connect the resistor to the output and ground. That goes to your line
in. What you're doing here is ignoring the '-' phase of the output and
using only the '+' with a DC blocking cap and a resistor to provide a
charging path for the cap. This way it won't make a pop when you plug
into the computer. This stunt is done very often when connecting a
balanced audio source to a consumer unbalanced input though the cap and
resistor isn't needed because there is no DC to deal with. You lose 6
db from reference level which is about right for consumer gear.
GG

	Electronics Forum Index -> Basics	All times are GMT
Page 1 of 1