[Sadaiyappan]

Is this equal to a DAC?  Is it okay to connect my amp directly to digital S/PDIF out?  I have a fiio E5 amp and I am using Beyerdynamic DT440 headphones.

 

[JoetheArachnid]

In short, no.
The S/PDIF is a digital signal output that must be converted to an analogue signal before being amped - this is what a digital to analogue converter does. I have no idea what would happen if you tried to listen to the digital signal amped, but I'm guessing it wouldn't be pretty. Imagine listening to dial-up noise times a thousand.
 
If you're keen on using the S/PDIF out probably the cheapest available DAC with that input will be the AMB gamma1, which you can build yourself or buy pre-built. However, there are other cheap-ish DACs but they tend to be USB input with analogue outputs and optical and coax digital outputs (no inputs) only, if that.

 

[FDS]

How would you do that? The E5 doesn't have any digital input (other than mini usb which is for charging). It's just an amp/preamp, not a dac..

 

[Sadaiyappan]

Okay I plugged in the mini headphone wire that inputs to the fiio E5 into the digital S/PDIF output of my laptop.  It works.  It sounds a little better, I think.  BTW I have a MSI GX660R-060US laptop.

 

[pejayjay]

S/PDIF transports a digital signal.  A DAC (digital-to-analog converter) converts the digital signal to an analog one.  The E5 is not a DAC, it is only an amplifier (it amplifies an analog signal). 
 
But since you're actually hearing sound, it means that you _are_ getting output from the laptop, but it's analog, not digital. 

 
Quote:

Okay I plugged in the mini headphone wire that inputs to the fiio E5 into the digital S/PDIF output of my laptop.  It works.  It sounds a little better, I think.  BTW I have a MSI GX660R-060US laptop.

 

[JoetheArachnid]

Okay, I've looked up your laptop's specs and looked at various pictures and I can't find anything that says there's an S/PDIF out anywhere.
There seem to be four jacks - one HP out (green), one mic in (pink), one line in (blue) and one which apparently should be 'side channels' (grey) but could well just be a line out. Assuming that you're using the grey one, since it's the only port that should give any output, the sound should be better since you're no longer piggybacking the E5 on the internal amp of the soundcard.
 
FYI, S/PDIF plugs ought to be orange, and coaxial. If you've got a plug that looks like that then I have no idea where you got it, or why sound is coming out.

 

[Sadaiyappan]

 
That gray one is the "Front Speaker Out", That one on the bottom is the "Digital" "Line out" S/PDIF out.  But it seems like the front speaker out jack is also the digital jack.  The green one that is darker is the headphone out that I have connected right now.  So your saying if I plug in my amp to the front speaker out it WILL sound better then the headphone jack?  And this brings me to DAC, does this mean my laptop sound card has a built in DAC (seems like it does because it has both analog and digital output jack) so is there any point in buying a DAC?

 

[JoetheArachnid]

Okay, I think you're confusing yourself here.
Your computer DOES have a DAC - any device that outputs audio from a digital source (computer, mp3 player, CD player). It's just that onboard sound, no matter how fantastic it's made out to be by the developers, is not very good. This is because both the DAC and internal amplification chips are cheap and nasty. An external DAC will bypass these internal chips and give you a better, cleaner signal to feed to your amplification stage. A line out will use the internal DAC but not the amp, so this is what you should probably be using.
 
About the S/PDIF - the only option I can think of is that the software is lying. If you were really plugging the amp into a digital signal it would not produce anything even vaguely like music. Perhaps the software is changing the HP out to a line out, which would explain the change in quality. No idea where the digital comes into it. If it sounds best plug it in there.
 
Yes, you could still benefit from an external DAC. Whether it's worth it is up to you.

 

[Gradoman]

probably combined 3.5mm optical & line out, like the iriver h140's. Some Creative Lab soundcards had this combined digital/analogue output

 

[joe_cool]

"does this mean my laptop sound card has a built in DAC"
ROFL and CGU
 
edit> Sadaiyappan: I checked your profile to try and get some context for your question. Apparently you are nothing! Fill out the forms!