Squeezebox and toslink

[dave2010]

I have to own up here. I wasn't pushing hard enough! Because I haven't used one of these cables before, I was a bit reluctant to push too hard. But if you give it some welly (into the SB Touch), then it clicks

I did wonder. Some of those optical cables do need quite a bit of pushing in. I've had exactly this issue with an SB3. However, some are flimsier than others, which might be one reason for paying slightly more.

Despite everything, I personally don't think there is any significant audible difference between expensive optical cables, cheap ones, and similarly for digital coaxial cables, providing the lengths are fairly short, and they are not totally rubbish. That doesn't mean that if I had a clear impression that there was an audible difference I wouldn't admit it, but it's very hard to be sure with self administered tests, particularly when one has spent money on an expensive "solution". No-one really wants to admit that the expensive kit doesn't make a difference if they've already bought it, and only a few suppliers will let you try.

Stan's optical cable seems reasonably priced, and may be a good compromise for those who feel the need for quality versus eBay or other cheapies.

[WAD62]

Anthony,

I'm still curious as to why you're not using the coax link, as it is better IMHO, and that's into a Beresford too...

[lovejoy]

I think the optical output of the SB Touch improves hugely with a decent power supply. I've been tinkering around with this over the last week or so and in stock form, I agree, the coax output is far better than the optical output. The optical sounds closed in and loses its dynamics and soundstage by comparison.

Yet, when you take out the stock power supply and put something better in there (not necessarily a linear supply), the optical output really opens up to the point where I *THINK* I now prefer it to the coax output, but that's probably slightly unfair as my optical cable is one of Mr Beresfords very good cables, and my coax is a very old Kontak Link 505 I've had hanging around for a long time.

[dave2010]

I thought I'd already written more on optical vs coax, but clearly using my iPad there are glitches and messages go in the bin - no comment!

Quite a few members here have said that they find coax better than optical links, but I'm at a loss to understand why. Is this based on a clear (to almost everyone who hasn't been touched by a magic wand) audible difference, or just wishful thinking?

If there is a real difference, what could it be due to? As far as I know the coding method for both coax and optical should be the same, and what goes in at one end as a stream of digital bits should come out the same whether optical or coax is used. The only slight differences which might occur would be due to errors - and realistically I'd expect more on coax than optical, and I suppose there could be some timing differences, though I'm not sure. Are there any other factors which are obvious to members here? Although sceptical, if there are real advantages to coax, then I'd be interested to know what mechanisms would make that a preferred method of linking kit together, otherwise it all sounds like snake oil stuff to me.

[electric beach]

Hi Touchy people

I think that sometimes the real issue is our definition of 'better'. Taking an overall impression from many, many posts here of comparison reports, the usual understanding is 'more detail', which I suspect in most cases means more striking leading edges to notes and a presentation with tighter bass.
(Will, you mention soundstage and imaging, but in what way - more sharply defined or more natural?)

I find that on both the Touch and my fat PS3, the optical out is a smoother presentation, more relaxed, more organic tone, darker background and can be played louder more comfortably.

I consider neither to be 'better'. Unless we are saying 'has better potential as a tool in balancing a system'. I get a big, buzzing bee in my hat with this western obsession with absolute performance judgements. In most cases we are talking about compromises and the best result must be that which treads the middle ground, balances the positives and negatives, yin and yang.

If it were one component used in isolation then OK, but we're working with a chain and balancing a system and a combination of attributes.

If I use the digital out then I can readily get more detail, immediately. But using the optical out I get a more natural foundation to work with, which allows other changes (e.g. speaker tuning, changing equipment supports, etc) that ultimately can result in resolving even more detail from a blacker acoustic, which is much more refined and of a realistic nature.

But that's my system. I'm not trying to say that the optical out is better. I'm saying there is no 'better' - unless you're only talking about certain attributes. With another amp, Dac, speakers, room, etc., then the digital out may give that elusive synergy that is at the real heart of not merely a good system, but a great one.

[Yomanze]

Bear in mind that these are supposed to be squarewaves (Credit: http://www.lampizator.eu/)

Toslink Trace:



Coax Trace:



Even better coax trace:



You can clearly see the inferior bandwidth of the Toslink trace which rounds off the squares quite heavily.

This is why Toslink doesn't sound as good!

If you prefer Toslink then there are a couple of reasons why this may be: a) it's easier to get coax SPDIF outs wrong, and yours is wrong or b) you like the "rounded" and perhaps even "smoother" sound of increased jitter. Genuinely, some people reclock their CDPs & prefer the previous (more jittery) implementation.

[WAD62]

Hi Touchy people
(Will, you mention soundstage and imaging, but in what way - more sharply defined or more natural?)

Hi Steve, I've been away in Spain for a week, hence my slow response...

As I stated in my original post I don't have a touch, I use a couple of SB receivers, and an SB3.

My comparison was done using an SB receiver and my Audiolab DAX, and all I can definitively say is that I prefer the sound produced by the two items when I use the coax rather than the optical.

Given that the 2 cables coax & optical were I believe of similar cost/quality (both Belken white pure AV, but this is an assumption), then the difference must be down to the relative implementations of each protocol on each device.

I'm not making a sweeping statement that coax is better than optical full stop, but in my small comparison, with my kit, I found the soundstage more three dimensional, better instrument positioning, and more realistic...using the coax connection.

Which actually disappointed me a bit, the reason I bought the optical was to see if greater 'electrical' isolation of my DAC from my SB, via an optical connection rather than a coax would improve things...and to my ears it most certainly didn't.

[dave2010]

Yomanze

Are those traces supposed to be audio output, or the digital data stream?

If the former, then you may have made the case for coax, otherwise it's not quite so simple, and would depend on how well the transducer at the receiver can decode the bits. Generally I wouldn't expect it to be such a problem.

[lurcher]

The "Even better" trace seems to have a bit of overshoot and possibly ringing, which could possibly confuse recievers more that the normal eye pattern.

[dave2010]

Actually looks like the digital data, which is differential Manchester encoded.
I doubt that this would be affected by the links shown, even the optical one.