[nuss75]

Hi all.
I was thinking about buying a DAC to my home stereo.

To use as transport I would like to use my computer and my DAP, it's an Iriver H140 with a miniTosLink.
Can Hifi sound easily be achieved with this?
I have some thoughts about interconnections and ultimately what I should buy. Becouse I want a lasting arcitecture.
Please correct me if my thoughts are wrong and I have misjudged anything. Because this is just speculations I would also be very happy on input about things that is right. And if you have, give me sugestions on a good standalone DAC for my purpose.

I was thinking…
Interface:

Since I can use a portable HDD connected to my USB port and digitally transfer an EXACT match of a file from the computer to the external HDD, the USB interface should yield an exact interface for a DAC.
I shouldn’t have problems of jitter and other things. At least as long as the DAC has a buffer and can thereby compensate for inconstant signal speed.
It should be like copying a file EXACTLY to an external HDD.
In this case the HDD is the DAC and the DAC internally change the digital “file”, which has been copied, to analog music. Hence the only loss of information and jitter production should be internally in the DAC.

But so why is everybody paying loads of money on cables to and from digital equipment like DAC: s when they can just use a USB connection?

I know the TosLink connection with the DAC has an other protocol (S/PDIF). Perhaps the protocol is a simplex one and hence don’t have error correction by retransmitting data and USB is a duplex protocol witch can send back an “ask for data to be resent” when the error correction notice a fault. If this is the case why use other connections than USB? Because that just lead to more sensitive data transmission witch yield a higher cost for optimal cables.

I read somewhere that a good TosLink cable should have a bandwidth of 11MHz I don’t know how you measure digital transmission in MHz but let’s say that every “bump” carry information, that means a 22Mbit/sec transfer.
And that is 2.5 MByte/sec (I use 1MByte=1000000Byte). The USB interface architecture gives a max transmission speed of 480Mbit/sec=60MByte/sec. Just the premium TosLink cables holds 11MHz generally they are 4-6 MHz.
That means a cheap USB cable should transfer up to 24 times or 48 times (if every Hz equals a bit data) as much data as a premium TosLink.

I mean Error correction, faster transfer, mass-produced, cheaper components and perhaps use it as a soundcard for your computer.
All this should lead to that USB is the right chose.

But I know that all Hi end Hifi has S/PDIF protocol with TosLink or Coax and nearly none has the USB interface.
Why is it worse in some way?

Test:
I tested .FLAC files on my H140 (Rock boxed) DAP with a Benchmark DAC1 Supposedly one of the best at least in bang for buck way (1000USD).
I used a TosLink to interconnect the two and got a very lousy result. I could just hear the mids. No dynamic in bas or discant.

Then I tried the same DAC with a CD transport it sounded marvelous.

I used a bad TosLink adapter with my H140 because I couldn’t find any good ones for the miniTosLink.
Is this symptom normal for a bad TosLink or is it the FLAC files or perhaps the player?
The ting is I want to use my H140 as my mane music machine because I really like the thought of having all music in one portable unit (it has 40GB).

I was thinking of opening my DAP and solder a better miniTosLink connector to the main board. Is this the way to go? Or perhaps just clean the contact since it is a female and I think a little dirt has gotten in to it.
Does anyone know how to clean a female miniTosLink?

This got quite long hehe

But perhaps it has opened up for a good discussion

.

Thanks for all input!