Hi Coen,

Appreciate about the jitter not sure about temperature as that is a longer term drift effect so for a quick check should not be a problem. Anyway I shall have a play later on.

Nick apologies missed your post - look forward to seeing the results of your tests.

P

So Peter - Just a thought  -  with a Dexa at the NOS1 and a standard pcie USB3 at the other end - if I tweak the Dexa "heavenly trimmer" and I am lucky enough to be able to match the Dexa clock frequency to the pcie clock frequency then in theory it should sound as good as two Dexa clocks if the noise theory is correct?

Paul

Ha ha isn't that typical of my luck (blown Dexa power supply) with only one clock working I cannot even play with my "heavenly trimmer". I wonder what my wife will make of that.

This is a really interesting stuff - we could soon know whether noise or data transfer errors are the culprit. We all know what Peter believes and my initial thoughts were that it could not possibly be data transfer errors could it?

I just cannot get used to this step backward in sound quality - I only heard two Dexa's for a few days - where is the bass, where is the crystal easy clarity?

Can't wait to get that Dexa PS due Monday ggrrhhh!!!

Paul

Hi Peter - I would be delighted to come over with modified NOS1 and modified pcie card oh and of course that bottle of scotch (ha ha I knew one way or another this was going to cost me a bottle of scotch).

And Peter I understand your point that more noise cannot be precluded just yet - but in the absence of further information my ears are telling me "much less jitter" but hey what do I know?

Anyway big thanks as you say to Nick because he started all this and actually much of my system is down to Nick (including bridged GC amp).

I will speak to Nick today to find out what days he can make it and I will PM you.

Cheers

Paul

No problem with 24Mhz they are not shown on the site but can be ordered as a "special" - actually it seems they are kept in stock.

I don't know what other options are available out there for 24Mhz clocks but for sure the Dexa's work well here.

As I said above the mods are not for the feint of heart and I learned a few lessons on the way so if anyone decides to go for it drop me a PM I can save you some potential problems with a couple of simple tricks. The first would be to get hold of a pcie card that has a surface mount crystal which is much easier to remove than the bigger metal can crystals which are not easy to remove without trashing the pcie card.

Also both Nick and I have made some other mods to the USB board which Nick detailed elsewhere on the blog mainly to with distributing capacitance. So at this stage neither of us can say for sure what the mods would do to a standard NOS1 although I would have to think that it could only be good!

Also I have been somewhat reticent to post about this because mods like this should first be looked at by Peter properly from an engineering point of view and there is a very real possibility of damaging NOS1 with the modification. So even now I wonder if I should have posted.

Incidentally I have another standard NOS1 here that I shall soon be applying the clock mod to so I will be able to report on that as soon as I get another pair of Dexa's.

Last night I sitting listening to my system with only one Dexa at NOS1 and wondering where the bass went. I cannot imagine what this mod will sound like with the Orelino - a mouthwatering prospect. But come January I shall be going to Mani's to hear would the modded NOS1 sounds like with Orelino's. Now there's a thought.

Cheers

Paul

I did not know whether to open a new thread with this or whether to respond under the "hunting for noise" thread anyway please move it Peter if you need to.

This post relates my experiences changing the standard cheapo 24Mhz clocks in the PC and NOS1 interfaces to high quality clocks. By some amazing co-incidence Mani dropped in for a quick visit at just the right time and was able to hear the results of the first part of the test and so I am sure he will add a short note about what he heard.

Regular readers will know that recently I went over to Nick's to listen to his system and in particular to listen to the impact of installing high quality clocks in the USB link from PC to NOS1. Nick's experiences have been posted elsewhere but since that visit I took the plunge and ordered a high quality Dexa clock of the 24Mhz variety. My thinking was that I had already invested in a Paul Pang USB3 pcie card (low jitter) for the PC end and so I would not need to go to the expense of a Dexa for the PC end would I?

So on to PART 1 of the test - Leaving the USB clock in NOS1 untouched I took a stock USB3 pcie card and removed the quartz clock and the 2 caps that are strapped across the clock leads and connected the Dexa clock powered by its dedicated high quality power supply. The Paul Pang low jitter pcie card had previously provided a welcome improvement and I really did not think that using a stock pcie card clocked with the Dexa would make much difference. Well I was wrong the Dexa powered pcie card sounded MUCH better.  When I first listened I thought there was less treble - but I soon realised that the treble was much smoother and more detailed. Going back to the PP card the treble sounded 'splashy' and ill defined less precise. Drums and symbols became grey and less precise in the mix. The mids with the PP card sounded 'grey' lacking tonal colour compared with the Dexa. Bass I would say sounded maybe slightly more controlled with the Dexa but no big difference really to my ears. But the biggest surprise of all was just how much better the Dexa clocked pcie sounded than the (already good) Paul Pang card. As mentioned above Mani heard that comparison so over to you Mani.


PART 2 this is where the fun really starts. I was already really enjoying much improved sound (I hope Mani agees!!) with the dexa clocked pcie card but I took a big plunge and ordered a second 24Mhz Dexa clock for the NOS1 end of the USB link. That is significant money for me I have to say. Especially as I was REALLY happy with the sound of the Dexa pcie card so I did wonder if it was possible to improve the sound quality further - but there again I had already heard what happened to Nicks system with this change so I took the plunge.

Making changes to SMD's on the NOS1 is not for the faint hearted a screw up there and it is big bucks to fix - there would also be the very considerable embarrassment of returning NOS1 to Peter for repair. I am sure that eventuality would have also cost me a bottle of whisky ha ha. Anyway having already honed my SMD skills on old boards lying around and then finally on the pcie card I dived into the NOS1. After a short nerve wracked time period I connected up NOS1 with Dexa clock running. So starting everything up in the right sequence I sat back to listen and all I can say is WOW what a difference. The already very good bass (and oh boy have I spent serious time getting the bass right in my system/room) was REALLY improved. Suddenly bass had real attack and speed and really excellent control (which are all qualities I thought it had before). But that was just for starters the already improved detail and subtly in the sound took another big step up. Also the tonal quality of the sound just superb. But what is really impressive is that sound just moves to a completely new level in sounding REAL and PALPABLE. Those are qualities I just do not get used to every day I switch on listen and smile. Put an album on, any album and I just do not want to take it off.

Vocals are just incredible - crystal clear - changing from Dexa pcie back to normal USB at the PC end and it sounds as though the singer has developed a lisp.

BUT a note of caution I found that the Dexa's need days to run in before they lose a slight hard edge. Even though the improvements were clear to start with there was a hard edge (also a tad hard and loud) but those problems start to disappear rapidly as the Dexa's burn in. Two nights brought about significant improvement but apparently 7-10 days are needed for best results.  I got to three days before a Dexa PS failed and the sound was getting to be truly magical.

Now as mentioned one of my Dexa power supply units failed after a few days so now I am listening to Dexa NOS1 and Paul Pang pcie (whilst a replacement unit wings its way over from Denmark). Now that should make me happy shouldn't it?  after all these are the best sounds I have heard in my system as of a few days ago. Well no I just cannot get used to the drop in sound quality NOT having Dexa's at both ends. It is really hard to go back. The sound is grey and flat now. The bass is just not in the same league. I cannot wait to get that replacement PS.

With 2 Dexa I can only describe the sound as sheer magic. I have not heard anything like it anywhere. IMHO now is the first time I have really heard what NOS1 and XX are capable of. And what I hear is something I have never heard from any source anywhere - nothing I have heard comes close it sounds that good.

So am I right in what I hear? well I cannot measure anything and why would improving the USB clocks make such a difference? That would take some thinking about but all I can say is something in a USB link with cheap clocks just cannot be working well - and maybe (as Nick pointed out) when we heard USB3 sounding better than USB2 there is a clue.

A note of caution. I can only relay my experiences with my system in this house my ears etc etc maybe some proper engineering and understanding needs to be applied. Dexa's are expensive maybe there is a better cheaper answer (Crystek PLEASE make a 24Mhz crystal). For sure though this is a revelation.

Cheers

Paul

Hey Nick - how about a photo of your rig as it is just now?

As Nick mentioned a Neutron Star dropped though my letter box last week watch this space .................


P

This evening I was lucky enough to see Geri Allen with Terri Lyne Carrington and Esperanza Spalding at the Barbican (part of the London Jazz Festival) playing Wayne Shorter pieces mainly (the great man himself at 80 years old was due to play later).

My expectations were high because Geri Allen is one of the greatest living Jazz musicians (IMHO) but I was taken by surprise these three female musicians produced some of the very finest Jazz I have heard live.

A female drummer / percussionist? I have to say I have not previously any convincing female drummer but Terri Lyne Carrington is astonishing and more than the equal of some of the finest men drummers.

If you love jazz and get a chance to hear this line up grab it with both hands.

Also as an added bonus the sound quality was superb - all in all one of the finest live performances of jazz it has been my pleasure to be present at.

Cheers

Paul

Just out of interest tonight I went back to my old PCie USB3 card just to remind myself what the sound was like before the Paul Pang card.

I did not listen for long - there is just such a big difference right from top to bottom (and including bass) the Paul Pang card lifts my system to a completely new level. Even my cat (if I had one) could hear the difference.

There is no doubt the bass is much better via Paul Pang - it may just happen in my system (who knows?) but for sure "it don't half sound good".

I heard a really big improvement in Nicks system with the improved NOS1 USB clock upgraded - right now it is hard to believe that I can get that sort of improvement in my system because it is sounding so good now. Anyway a reference grade 24MHz clock is on its way so I should know in a few days.

A mouthwatering prospect I have to say. I can't wait but one thing I will be doing first (before upgrading the NOS1 USB clock) is to remove the clock from my stock PCie USB3 card and try the reference clock in its place just to get compare with the Paul Pang card.

Watch this space!!

Peter I did understand what you meant.

Cheers

Paul

Peter - I totally agree with you it generally takes me about a week of much listening to determine the real merits or not of a change.

But in respect of clocks on the USB interface I would have to say that improved clocks is a total no brainer regardless of XX settings (to these ears at least) - the reduction in glare and hash is immediately obvious OK extended listening is always needed but I just cannot believe that I would ever change my mind on that particular one (but hey I have been wrong before). Of course noise profile is all - and each system potentially is different so I can only comment on what I hear in my system and in Nicks.

But there again I remember installing the PCie card with the banks of capacitors and that made a big improvement only to be totally negated when you changed XX for W8 mmmm.

Your mention of XX settings is very relevant. Since moving to W8 XX settings became much less important in my system. In my system with the Paul Pang clock in place XX settings now have a bigger effect. Also at Nicks yesterday with improved USB clocks XX settings become much more important. Nick was able to "tune" the sound of the system using XX settings.

 

 

Just a further note about the bass heard in Nicks system. Nick and I agreed on just about everything we heard but I had a slightly different perspective regarding bass with the Paul Pang card. It certainly was very different with the Paul Pang card but for me it was very difficult to determine if it was better or worse. The main reason is that the bass in my system is very different to Nicks and it was difficult for me to establish a reference of how the bass should sound. It is a shame we do not live closer because it would be interesting to hear Nick's modified card in my system. Short of doing that I shall try my old standard PCie card versus the Paul Pang card later this morning.

Hi All,

I have just returned from Nick's. Thank you Nick for great hospitality yet again but especially to Claire for putting up with this "Hi Fi Nutter" taking over her husband for most of the day. Even more important thanks to Claire for the banana and date cake which is probably the best in the known Universe mmmm!!!

On this visit I took my NOS1 and the Paul Pang PCie modified PCie USB board.

For those who do not know - Nick and I have systems (at this time) that are very similar we have the same bridged - bi amped gain  clone amps (totally identical!) our NOS1's are modified but both are identical apart from Nick has replaced the USB 24Mhz USB clock in his NOS1 USB board with a higher quality low jitter VCXO version (see Nicks recent posts on this). My NOS1 currently has the standard clock as supplied. Nick's PC has a PCie USB3 card but Nick has replaced the clock with a low jitter VCXO - I have the Paul Pang low jitter PCie card.

So where to start? first of all I had to get my bearings so we installed my NOS1 and the Paul Pang PCie card in Nicks system. Nick has Avant Garde Duo speakers and mine are home made transmission lines. There is a big difference in the sound between the two but it is much to do with presentation (yin and yan I would say I will post separately on this subject).

For me we were now listening to the sound of my system but through Nick's speakers (no surprise there) OK a big difference in presentation but very recognisable. For Nick he felt that the Paul Pang PCie card really added something for the better clearer more natural sound.

So then we replaced the Paul Pang PCie card with Nick's modified PCie USB3 card (with low jitter clock etc) and the clear winner was the Paul Pang card which was clearly better in sound quality - less sibilance and "mush" on voices generally with a clearer and better delineated sound better tone. There was nothing subtle in the difference. And as Nick's modified card was better than a standard PCie USB3 card the Paul Pang card really was a big improvement. This was similar to my system. So we put the Paul Pang card back in for the rest of the session.

Then we swapped my NOS1 out and replaced it with Nick's NOS1 with low jitter USB3 clock. There was a *BIG BIG* improvement in sound quality that was obvious from the first note. Again it was an improvement in the same areas- reduced hash clearer cleaner sound. There was nothing subtle in this improvement it was a big step forward.

I shall be replacing the USB3 clock in my NOS1 as soon as I can with a high quality low jitter version.

It is always very difficult to comment sensibly without being able to measure what is going on but to my ears (and I think Nicks also) improving the USB3 clocks at the PC and NOS1 brings about probably the biggest single step improvements in sound quality that I have heard and it applies to both our systems (that is apart from Nick's change in mobo which really was fundamental).

More to come on speakers ...... watch this space.

Cheers

Paul

Hi Nick & Peter,

I have noticed this "problem" in the past with time stability. Some time ago I tried to judge if it was impacting sound quality but I did not really hear any difference. But since then there have many changes in my system so I will have another listen tonight.

Cheers

Paul

Hi Anthony - I understand and agree about the noise aspect and I think Nick's previous posting about it points clearly in that direction but as I had a linear supply to hand I thought it would be worth a try as it only took a few minutes to set up. Well it should have only taken a few minutes if I had not corrupted my BIOS doing it 

Always good to see more than one "Nosser" getting the same results.

Cheers

Paul

Further tests with the USB Audio Grade PCie card. The card comprises a normal USB3 PCIe card with a piggy back card that has a low jitter clock and a silver output isolation transformer. The piggy back card picks up 5V from the incoming MOLEX connector which I disconnected I then connected a dedicated linear 5v supply to the piggy back board. The supply from the PC SMPS remained connected to the molex on the main PCIe card.

This seems to be slightly better than having both the PCIe card and its piggy back card from the same supply from the Seasonic SMPS. But it is a small improvement I would say.

The piggy back board seems to have a DC to DC converter but it has a big heat sink glued to it so not easy to see but anyway it probably produces 3.3V for the clock. It gets the heat sink warm to the touch so it is probably a regulated supply rather than "chopped" supply - it would be interesting to see if a battery supply 3.3v direct onto the clock improves things. Well maybe but it is not an easy thing to do with this board maybe something to do on a rainy day.

Cheers

Paul