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 there an 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
--- Connect either of the chip's outputs to the sound card line in through a 100µF capacitor and connect the chip's pins 6 and 3 to the sound card ground. Let the other output float.
Connect the capacitor's + terminal to the chip's output and the - terminal to the sound card's line input.
If you don't want to hear a "POP" when you apply power to the chip and, assuming the input to the sound card is DC coupled, do this:
Vcc | O | +-----+--> | | | | +--+--+ | | OUT|---[+100µf-]--------+---------> TO SOUND CARD | +--+--+ | | | \__CHIP | | GND | | C +---[+22µF-]---[100K]--+--- B 2N4401 | E [1M] | | | GND GND
-- John Fields
[...] Thanks John, just what I wanted!
When the supply is switched on the transistor acts as a clamp on the output until the 22uF cap is charged up. But watch out, Dave! The TDA7052 is rated for up to 18V supply voltage, and can create output swings of well over 13V peak-peak when powered from 15V or more. 13V swings will drive -6.5V peaks to the 2n4401 collector, pulling the base to -6V, and approaching emitter-base breakdown. This is bad and should be avoided, especially with high currents. However, TDA7052 supply voltages of 12V or less should be OK.
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Thanks,
- Win
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