Quote:
@VFR750A45 make sure that the impedance is correct.
Remember the output must be flat and without as little as possible phase turning
The best thing to do is to create a buffer (x1 amp) so the output will be stay the same in volume but as in the word 'buffered'.
The influence of having a low impedance input of the transmittor (or other device) connected to the output of the audiocard is then highly reduced.
Since we are only talking about max 100KHz a simple opamp will do and preferably it needs to be as close to the audiocard as possible.
As Bojcha says most of the time the Realtek are good ..... but it is what is behind the chip. Like putting a Porsche engine in a 2CV will not get you good results.(except for fun)
I have seen motherboards (and cards) with a 0,1uF capacitor between the output of the chip and the connector, and that is no joke.
Somehow I like to place coax like RG-58 or RG-59 between a soundcard and a transmittor. Shielded properly and very low capacitive since the middlepart is quiet a distance away (and always) from the shielding.
That the coax is 50 or 75 Ohms has nothing to do with the impedance about what we are talking since that relates to electro magnetical impedance.
i have a RG59 cable RCA/BNC i tested it later, it is in 75 Ohms and my soundcard had RCA output, it's ok for the test