Considering most of us might be using average consumer grade receiver/amplifier, does to use the spdif/toslink out of a soundcard is so worth it? Are receiver's dac ultimately better to use than the soundcard's one ? Is using cheap cable in a noisy environment, such as the rear of a computer, is so harmful to analog signal that we prefer to use anything else after for the dac job ?
Oh God yes. That's not the problem - the problem is the Holy Grail, something that outputs opl3, digital sound and bug free midi over spdif on an ISA sound card preferably without PnP.
lets take we only have a very simple soundcard that can only output stereo pcm over the bus. You have the choice to use spdif or dac to your receiver, what road would you go ?
Spdif all the way. Analogue output is horribly noisy on early soundcards, plus they depend on capacitors which are degrading over time. I use a high quality external headphone DAC for most of my retro PCs and it's superb.
