Home › Forums › temp › Using PC for audio source – Is earphone jack sufficient? › Noise Floor vrs Working Level
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If your PC soundcard has a line out jack, that may be a better choice. I’ve found that the soundcard amplifier for the speaker/earphone output jack can be noisy especially with inexpensive soundcards. The line out jack won’t drive a low impedance load like a speaker but is usually quieter regarding the noise floor.
If your transmitter audio input is designed for line level input, it probably has a 10 K ohm impedance that would work well with a line out jack. If, however, the transmitter audio input is designed to be connected to a speaker/earphone output, it may have a low impedance that would not work well with a line output.
My PC only has a speaker output jack and is connected to a line level input at the transmitter. That works OK as the low impedance speaker jack output can drive a high impedance line level input and the audio level is high enough above the noise floor that it’s not a problem.