Low cost DAC with Optical input based on PCM2902 for connecting smart TV?

[Rolandas3]

Hi all,

Some time ago I have build a PCM2902 based sound card. The chip itself has Digital IN, Digital OUT, Stereo ADC & DAC outputs. Mostly I was using it as a sound card for a laptop.

Now I am looking for a cheap solution to have a possibility of connecting my TV to an amplifier. Unfortunately (or fortunately) my TV has an optical output as well as possibility to connect headset. I am looking at my soundcard as a first step to make it happen:
- I have connected TOSLINK receiver TORX173 to the digital input of PCM2902 and then DAC output to an amplifier. I power my card from USB. Unfortunately it doesn't work

I have checked TORX173 output levels with a scope. It provides something like 2.5V ("High" level). Power supply for TORX is 4.6V.

So now I have doubts:
- I am trying to use PCM2902 not according to specs, e.g. I cannot use it as a DAC with optical input (IMHO it should be possible)
- something wrong with TORX179 - too low levels, too low supply voltage, etc
- maybe PCM2902 Digital IN doesn't support bit rates provided from my TV (Samsung UA55JU7002)

Any live experience or good advises where to start from?

Big thanks in advance

Rolandas