With the standard pp card I posted before that I felt it was delicate and natural sounding, but with less drive, less highs and especially less bass.

That is compared to my standard oem usb3 pcie card (earlier version of the NEC chip with onboard switching regulators for the chip and 5V). Reversely this sounds more loose and melodious, together with more realistic highs and dynamics.

Now with the little modification (secondary grounded near NEC chip instead of clockboard), I concur with Paul. i have to add that the sound is still a bit less dynamic (smaller?) and it seems more tilted to the right channel. The latter could be or is a frequency balance left-right thing.

Is this the kind of report that is addressing your question?

Next I plan to do some psu connection experiments, before taking the plunge to a one-clock setup.

Regards, Coen

OK using Mani's standard NOS1 I have been listening with it connected to a mobo USB2 port. Both USB2 & 3 on the mobo switched on. I guess there is no need to describe what I hear because most NOS1 users out there should be familiar with the SQ.

Next I switched over to the Paul Pang card - there is a clear difference in sound quality. The sound becomes "fuller" less thin definitely a more "analogue" sound. Perhaps "Lush" would be a way to describe it and at first listening I would have said that it was tonally better - but now having heard the Dexa USB I am not so sure maybe it just sounds "fuller".

However, with the benefit of now having listened to the Dexa clocked USB link it is clear that the Paul Pang card does not improve on the clarity of the sound. But it certainly changes it.

Hope that helps

Paul

I have not done the comparison with XXHE/NOS1, but when I did it with my previous dac and computer setup the Pang card brought better resolution across the highs and low but most importantly it brought a more balanced presentation i.e. there was no bloated bass or shrieking treble..just balance, and smoothness.  But as I said earlier, that was with my previous dac and computer.


Anthony

Mmmm  as it happens I have one of Mani's NOS1's here (totally standard no mods) so I can compare it with my modified NOS1 with Dexa's. I can try any combination (1 Dexa, 2 Dexa's, std NOS1, modified NOS1 etc) except I do not have a standard Pcie USB3 card - both mine have been hacked so they no longer have crystals in them one of them is being clocked by a Dexa.

So for various reasons the only tests I can do are against mobo USB2/3 which I can turn on.

Is that any use to you Peter?

The only other thing is I have to re tune my ears because I have been listening to a number of combinations and I am starting to show the first signs of madness (OK maybe not for the first time.......)

Oh and of course I have a Paul Pang card in and working...

Cheers

Paul

Quick question :

Can anyone (or everyone) describe what happened to the sound when Paul Pang's card was used instead of a normal NEC based USB3 card ?

I'm into the 5th track of "some" setup and ready to post about something strange and that maybe I found something ...

Peter

Coen hi,

I am not aware of the spec. of the tranformer used by the Paul pang card so difficult to comment there but concentrating for a moment on my DIY clocks build and the Dexa clocks. The main application of the output transformer used in both of these is for ethernet network transceivers signal isolation, bandwidth is rated >100Mhz. I guess to preserve the signal waveform the transformers effective maximum pass band will be much higher than this.

What has struck me with the experiments on USB clocks so far is how much more that jitter reduction seems to impact on sound quality than clock RF impacts sound as HF components of square clock waveforms increase.

Given this my thinking is that bandwidth limiting the clock waveform might improve general electrical noise but is likely to also impact phase performance which in turn could have a big impact on sound.

Im still very keen on clock transformer decoupling as it is appears to take ground loops on the clock connection out of the picture which can otherwise be a big problem for sound quality. But generally it think high bandwidth passive components on the out put of the clock may be the best way to go.

Kind regards,

Nick.

I am glad I am not the only one with the most easy appliances not working at all. So I did not tell it yet, but the most basic connection in my special situation already does not work (clocks normally running on all sides). So I am as far as no NOS1 to be seen anywhere.

You guys should see what's all done to deteriorate further and further to come to the conclusion in the end that the base "configuration" even doesn't work.
The only thing what keeps on working is that my PC keeps on booting. Ok, once out of two times, so that is progressing also.




PS: We just moved the lot out of the listening room, Waiting for you now Coen. That's more easy. Too many variables here at this moment, while I apperantly seem to think that all will work but maybe one, while it is the other way around and I will not know which one.
LOL

LOL

Coen, aren't we getting crazy (by) now ?

I must say that I have applied similar elsewhere by means of lowering the (official) voltage. So if you are crazy I am the same. But careful now, because while my reaons were exactly the same (hey, we do get along, don't we ?) in your case there's theoretical jitter in order, while in my case it was unrelated to that. So Coen, keep in mind - we are on the track of "no jitter can be in order here" but from the other angles (stability - spreading peaks) we might be after all and actually it is my best bet at this moment.
Btw, spreading peaks sounds nice as a phenomenon, but that can be in control, while your idea here will spread too, but now out of control. So there is a didference.

So I am sure you see that flattening signal tops is the worst for jitter and it should be the other way around, and I'm just saying it because it may have skipped your (net) consideration.

But once again : great stuff in itself.
Peter

Thanks Nick, this is helpfull!

The signal loss would be due to the dc component saturating the transformer core.

Next to providing galvanic isolation, which the capacitors allready can do if you would add one on the other leg, I think the benefit of the transformer is that it acts as a band pass filter. by its nature it removes the steepness of the signal. This leaves a signal with less unneccesary hf energy that would be detrimental to the sound.

Regards, Coen

Coen hi


My DIY clock used capacitor decoupling on both output of the clock module in serise with the transformer primary coil and also on the secondary of the transformer on its output in serise before the signal connects to either the NOS PCB or the PCIE USB card.

I tried direct coupling of the clock module to the transformer primary and the transformer secondary to the PCB clock inputs but this resulted in a loss of signal amplitude and would not drive the USB PCIe card and NOS PCB IIRC.

Hope this helps,

Regards,

Nick.