Tír Na HiFi

I'll have a read of those links later John. Thanks. You're quite right though in that a lot of design techniques look and sound great in theory or on paper but when you have that physical chip/board in front of you things are not always that straight forward. All week I've been chasing a signal reflection on a board that's so bad it's triggering an unwanted software routine on one of the DSP's. Just when I think I've eliminated it, it pops up somewhere else.

jkeny wrote:In your described technique, is there one problem - the asynchronous clocking which will require some form of PLL to prevent buffer under/overflow?

The HDMI has provision for a signal to be sent back to the source to control the timing of the output stream. So the buffer is being monitored for when its approaching under/overflow and a 'command' is sent back to the source to tell it to marginally increase or decrease its clock speed. So the buffer has always enough data and in the correct order. There are further complications too in that that data over HDMI is usually encoded and/or encrypted.
Perhaps this is someway the same as the elastic buffer that you mentioned in your last email.

Fran & myself met up in Brian's for an audition of the Hiface DAC Vs Brian's Wadia 850 (Highly modified). Thanks Brian for the hospitality & the interesting night. I won't post up my impressions/conclusions before them as I promised I wouldn't (It might appear as self-promotion :))

One thing I want to note is that since I have been experimenting with my balanced headphone amp, I've been doing some listening to the Hiface. One thing I noticed was that when I clocked on an Windows folder I heard the open folder sound in the headphones. This didn't happen on Win XP as using Kernel Streaming (KS) output on Foobar took over exclusive control of the USB audio card & thereby avoided windows mixer which is detrimental to sound. In Windows 7 Foobar using KS output uses the windows mixer.

Anyway, long story short :) - I changed the output in Foobar to Wasapi & the sound improved significantly - cleaner, wider, more 3D sound stage, all the usual :)

So I guess, it's ready for a comparison against the dCs system Ciaran, if you are interested?

jkeny wrote:Fran & myself met up in Brian's for an audition of the Hiface DAC Vs Brian's Wadia 850 (Highly modified). Thanks Brian for the hospitality & the interesting night. I won't post up my impressions/conclusions before them as I promised I wouldn't (It might appear as self-promotion :))

Well John it just goes to prove one thing,when three so called Hifi nerds are at odds to tell the difference between A"Wadia"&B"Hiface".

Ok let me explain,the exercise involved playing the same tracks from a cd at the exact "and I mean to a millisecond"matched time,and volume,thus making it totally dependent on how each of us interpreted what we were listening too.CD on the Wadia,and downloaded version on the Laptop feeding the Hiface Dac to the Airtight ATM2 amp.I personally found, at first, quite easy to tell the difference between them, favoring the Wadia,finding it presented a fuller,richer,a slightly larger sound stage.So much for first impressions.

As the night wore on, I had to admit that I was finding it increasingly harder to tell the difference.Switching from one to the other,served only to highlight the very small difference between how both devices presented the same piece of music.Overall I would have to say,if I hadn't purchased the Wadia "of which I'm still very fond "I doubt for the money I would find anything that comes even close to the Hiface.John I can only wish you luck with it,and I strongly advise anyone thinking about upgrading, to at least give it an audition.Tis sick I am.

Brian.

Thanks Brian,
Your words of support are much appreciated. No need to have any buyer's remorse, that Wadia is built like a tank, both outside & inside. Yes we had it opened up :) for Fran to do some gain adjustment on it at the request of Brian. It is a wonderfully realised piece of audio kit & shows a high degree of careful design. Also it is just what you want - pop on a CD & listen, no faffing around with PCs, software, drivers, etc. Oh, oh have I said too much & put everyone off computer audio, doh!?

BRIANO wrote:Ok let me explain,the exercise involved playing the same tracks from a cd at the exact "and I mean to a millisecond"matched time,and volume,thus making it totally dependent on how each of us interpreted what we were listening too.CD on the Wadia,and downloaded version on the Laptop feeding the Hiface Dac to the Airtight ATM2 amp.I personally found, at first, quite easy to tell the difference between them, favoring the Wadia,finding it presented a fuller,richer,a slightly larger sound stage.So much for first impressions.

As the night wore on, I had to admit that I was finding it increasingly harder to tell the difference.Switching from one to the other,served only to highlight the very small difference between how both devices presented the same piece of music.Overall I would have to say,if I hadn't purchased the Wadia "of which I'm still very fond "I doubt for the money I would find anything that comes even close to the Hiface.John I can only wish you luck with it,and I strongly advise anyone thinking about upgrading, to at least give it an audition.Tis sick I am.

Brian.

That mirrors my expierience almost exactly.

Yes indeed. All of a sudden it seems that very high quality sound is now easily available from a pc or laptop......

As Brian has said, I found that it was almost impossible to tell the difference in the switching test, but yet on longer listening to each individually I came away with the impression that the wadia had slightly more body than the dac which I thought had a more open sound. However the devil is in the details and I know from talking to John that the playback used software volume control which means that the source was hobbled from the start. We did this to match levels but as is often the case there was an unknown factor. The same situation occurred in Ivor's I believe.

So it seems that there is a bit more to wring out of the dac.........

Fran wrote:......

So it seems that there is a bit more to wring out of the dac.........

It certainly seems that way:
- I believe the digital volume control turned down in Foobar to -10dB seems to limit the output to 14bit resolution rather than 16bit.
- The move from Kernel Streaming to WASAPI has made a big change in the sound also.

Let's see how it shapes up Vs the dCs system if Ciaran is still keen?

Ciaran,
I've PMed you to see if you are interested

John