SPDIF Cable, longer is better! (Interesting articel)

[Flecko]

http://www.positive-feedback.com/Issue14/spdif.htm

In my case I profit very much from using a 5m spdif cable and using no usb cable for my hi-face.
Greetings
Adrian

[PeterSt]

Or have a *real* 75 Ohm impedance ...
(which usually can't be achieved)

So, longer cables make the reflections (of wrong termination) arrive to late / die out underway. But I'd say the signal itself degrades with it and it's just a wrong solution. Oh, it can workout for the better, but arrange for the real 75 Ohm would again be better.

My 2c.
Peter

[Raj.V]

Aha! From the posts above, now I understand why ...

I read that jitter was susceptible mainly after USB-SPDIF (Hiface) conversion and that the data through USB to Hiface was robust. So thinking myself to be smart I bought a decent USB cable (female end) and connected the Hiface directly to the DAC with a male/male RCA adapter. I was expecting magic and I was very wrong.
The connection of the Hiface with SPDIF to the DAC was just superior. I couldn't understand it...

So I took it further... and connected the Hiface directly to my Laptop and DAC (no cables at all but with male/ male RCA adapter - good quality). The SPDIF was still way superior. So presently I am just sticking with the SPDIF cable.

Thanks for sharing, Flecko!
Raj 

[Flecko]

I tried a b test.
a: Direct plugged to the dac with 5m usb and
b: with 5m usb and 5m spdif.
Unfortunatly my system was not good enough in this config to make a clear statement. The long usb cable decreased the sound of my outofthebox hiface very much.
But I can say for sure, that it is better to use a long spdif (50€ type) cable on the hiface than a long usb cable (10€ type).

But I'd say the signal itself degrades with it and it's just a wrong solution. Oh, it can workout for the better, but arrange for the real 75 Ohm would again be better.

I didn't wanted to say this is the best or only way. Just an inspiration for people who have a similar setup as I.
In my case, I have about 4m from pc to dac (spdis input). If you consider boundary conditions like that, you just have to get there somehow. And in this case it seems to be good.
It is questionable if one can manage such a tight design. Even the best cables have about 0,5% to 1% deviation from 75Ohm. And the designers of the electronics are aware of this problem (at least some of them) and try to go as close as possible to 75 Ohm with theire input and output design. There are also different approaches for that problem. Audiophilleo tries to avoid the refelction problem with a very fast output stage. Art Legato gives a 5m spdif cable to his usb/spdif converter. Both serious designs I think.

@Raj
I think the hi-face power supply also suffers because of the usb cable, especially if they are long. I tried different length from 0-4.8m and I would say, the longer the worse for usb-powered devices.

[GerardA]

For my Hiface with BNC I tried a 10m cable with RCA's and adapters and it sounded more silky.
If you use the  RCA-fitted Hiface then 75 ohm's is impossible to achieve so then I guess a long cable is always a good option.

Another improvement is a 12- 20 dB attenuator as proposed a.o. by JKeny.
It is supposed to attenuate the reflected signals as well as the main signal but the main signal is still strong enough because the hiFace gives enough juice.
and the battery option sounds worthwile..

[PeterSt]

Another improvement is a 12- 20 dB attenuator as proposed a.o. by JKeny.

But you do know why, don't you ?

...

Because the HiFace has a way too high output level, so the reflections are also way too high, and now can easily be seen as falling/rising edges ...

So, Flecko's (or Steve's) general idea is still good, but the HiFace begs for it. It's just wrong to this respect.

Peter

[Flecko]

Another improvement is a 12- 20 dB attenuator as proposed a.o. by JKeny.
It is supposed to attenuate the reflected signals as well as the main signal but the main signal is still strong enough because the hiFace gives enough juice.

I tried this tweak. I chose a 6db filter because of two reasons.
1: The shop just had that one, and it isn't actually a attenuator but a splitter which reduces the signal about 6db and
2: the other thought was, that a 6db attenuator already reduces the signal to 50%, 12db would be 25% and 18db 12,5% of the original signal and that seems to be a little much.

I can say it changes the sound and I would agree with Keny, it is smoother. But smoother is not necesarily better. But in this case it seems to be better because the stage becomes more 3D. I recognised no loss of bass but I am not sure because of the dynamics. Without that tweak it sounds a bit agressiv and this is so far, not clear to me if this is good, if you think about dynamics or bad if you think about distortion. Without the attenuator it sounds a little distorted to me. I will listen some days and then decide if I order a proper attenuator.
If this turns out to be a good thing, there is the question if this is a hiface specific error or just a common problem with spdif signals. It might be both.
Greetings
Adrian

[Flecko]

After some more listening I can quite sure say, that the 6db attenuation will help the hiface giving better sound. It is more involving, softer but no loss of details, a little more musik in the room and more 3D. But I will not buy the attenuator. I decided to buy an ART Legato. It is a much better design and will not need the attenuation. As peter said, the attenuator helps the hiface because it has no perfect design. But with a better designed device, reflections can be much lower. Example (from Pat): If you have 20% reflection from your dac input and 20% from the source you will get 4% reflection to the input to the dac again. The 6 db attenuator reduces this to 2%. Without an attenuator and a propper source, in this case the legato, you have 0.13% reflection that get into the (still 20% reflecting) dac ->no attenuator needed. It is not said that the hiface is so bad, that it has 20% reflection but it will be far from the legato. So I ordered one.
Greetings
Adrian

[GerardA]

You checked this site: http://www.audiophilleo.com/comparison.aspx  ?

[Flecko]

You checked this site: http://www.audiophilleo.com/comparison.aspx  ?

Thanks but I checked it already and think from what I read that the Legato will perform better if you just looking at the main function, "converting" usb to spdif. The audiophillio 1 has nice features but nothing that I need. A direct comparison of the two devices would be interesting but it is not available in the net. At least I found nothing.
Greetings
Adrian

[Flecko]

Just want to update this thread. I am ill (damn weather) and have time to play with my hifi-system. I planed to buy the legato but it was not available for al long time, things changed and I canceled the order. One interesting thing is, that upsampling was never really working for me and I had the best sound with 44.1/16bit. 88.2/32 sounded refined but also laked dynamic. It was one step forward and two back. One day I tryed the 24bit setting and felt it has the analog sound like 32bit but is as dynamic as 16bit. That was a nice improvement and I listened to 44.1/24bit. In the last weeks I tweaked the bnc input of my dac. I now use a " bnc feed through jack". I connect a bnc cable from the outside of the dac and instead of soldering twisted pair at the inside of the dac I can now connect BNC also from the inside! So I can go 75Ohm straight to the board. This was a quite hearable improvement. I tell this because I think it explains why today, as I am experimenting with xx, doubling has become an option for me again. Before this tweak I lost dynamic and gained a refined sound. I didn't liked this. Now it sounds refined but without losing dynamic. (Maybe the upsampled signal is more sensitiv to the transmmision over spdif?)  But if I get best sound with 88.2/24bit why buy a 44.2/16 bit only device? Doesn't make sense anymore and that is why I will try the audiophilleo2 instead. Should be able to improve over my standard hiface.
One thing lasts. 24bit ist still better than 32bit. If someone like to try this out and tell me what he hears, it would be interesting.
Greetings Adrian

[Marcin_gps]

Are you talking about 'DAC needs' setting in XXHE?

[PeterSt]

24bit ist still better than 32bit. If someone like to try this out and tell me what he hears, it would be interesting

What I heard from those who can choose (which are very few !), they tell the same.
Theoretically it implies 3/4 of the "system load" in almost everything. So that can be a reason ...

Peter

[Flecko]

Are you talking about 'DAC needs' setting in XXHE?

Yes

24bit ist still better than 32bit. If someone like to try this out and tell me what he hears, it would be interesting

What I heard from those who can choose (which are very few !), they tell the same.
Theoretically it implies 3/4 of the "system load" in almost everything. So that can be a reason ...

Aha!
Thx for the quick answeres.

[Flecko]

Very strange. Even ArcPred works now. It alwas had a better focus on the instrument but added a strangeness to the sound. Now it is just incredible how much realness it provides. I cleaned my system with tuneup and using a function of tuneup that is called turbo mode. This defenitly improves the sound. I would try vista but the cd I have doesn't install. Don't know why. But sound is great even with w7.