Peter,

From your first post I got the impression that the Orelino is overall a much better speaker than the Oris. Since it is based on the same mf/hf driver and horn, all the difference is made by improvements in the range 200Hz and below. It surprises me that this changes the overall sound so much, because 70% of the spectrum stays the same. Did Bert also develop a new filter for the mf/hf?

Regards, Coen

Alain I checked this and the only events that areclogged are at the boot time.

The positive part is that is is very systematic every other boot. I'm very shure that it has an audible impact. This makes A-B ing of mobi tweaks that need reboots a little tricky.

I tried to start logging of all events but that didn't go probably because of minimised OS.

What else to do?

Regards, Coen

That is two drivers in"isobaric" mode for extra low distortion. The horn is diven only by one. Or am I mistaken?

Regards, Coen

P.s i am talking about Manis speakers

This sounds all very promising!

I plan to visit the x-fi on sunday mostly to hear this system.
Hope to meet you there,

Regards, Coen

Thanks for the replies.

I've gone twice from minimised to normal and back.

It looks like some service that is running ( from the boot on) every other boot.

Regards, Coen

This is so persistent that it deserves a separate thread.

The issue is that win 8 needs two boots to work properly.

Every other boot the music suddenly stops after some playing (will determine if this is a fixed interval next time). The first stop is accompanied by fierce HDD activity, further stops nothing special is goin on.

Moving the mouse gets the music playing again until it stops again, etc, etc.

These stops disappear after rebooting. SQ is also slightly different. The next time I boot the stops are back.

regards, Coen

A few remarks from my side:

- how about the monitor? Where do you plug it in and how is the earth connected?
I have best results if it is plugged into a different powerreceptable from the pc. The monitors switching psu remains allways connected....

- as I went om inspection in my own house it turned out that I don't have a real earthing since they replaced the incoming water with plastic pipes and a new meter but left the connection to the fusepanel in place. That left me under the impression that I had earthing but it was actually the safety earthingh of the water system  .
Safetywise I have two Ground Fault Circuit Interrupters so no lethal situation arises, however all groundsh&t is shared between devices that are connected to the PE. I just requested a few quotes to get a proper groundbar in place.

Now both the PC PSU and NOS are connected with a common PE on the powerstrip but to no real earth. Measuring voltages across the usb is a little hard, but between pc usb and amp-in they match the NOS1 offsetreadings.

I still am under the impression that most noise is generated by the poweramp and that all other stuff is below that.

Regards, Coen

That would definitely exclude the NOS from the picture!

My memory about this issue starts coming back:
I managed to somehow create a short circuit on the 5V in the NOS ESD protection chip. This immediately shuts off the usb ports on the pc and renderes the NOS1 unusable. Awaiting the NOS1 repair I played some tunes through the mobo soundcard, where the PC noises also where very apparent. Same thing happened  when I swapped the PSU to my other completely different internet pc. Using another spare PSU, noises where geatly reduced. The PSU causing the noise was decommissioned.

The thing is I didn't start out with these noise issues. They appeared likely as result of some failure somewhere, the PSU being prime suspect. I cannot exclude the possibility that the fault also partially distroyed the ESD chip making the NOS1 transparent for the noises. The ESD chip could have failed later completely by something else.

This remains speculation, because I never internally examined the suspect PSU nor the NOS1 on this matter.

Regards, Coen

If that is true then:

You don't have to run through the central ground point. A thick wire parallell will do the same thing, maybe better because it will be shorter (less impedance and much shorter loop).

Regards, Coen

Hi,

The 5V of the USB cable is internally protected by the ESD protection chip in the NOS1. So it is connected. I can imagine some mechnisms that noise from the 5V line will be entering the NOS circuit, but those will be fairly small.

I toyed around with powercables, powerstrips en earthing (as far as possible here), but the system remains silent in all cases, that is the PC noise (if present) is swamped by the noise of the amp that is allready quite low.

In the time I had a flawed psu that distroyed -according to my measurements and theory- the internal NOS1 ESD protection chip. So I switched PSU to Seasonic X-400 and got a repair from Peter (actually Cisca!). Can't remember ever having any noise problems after that. That is with the regular USB cable.

My hunch is that the noise on the usb 5V is able to enter your NOS1 circuitry as a result of damage. In my view this noise problem could point to a half blown ESD protection chip; the result of one experiment too many (and I also use a tube amp...). I could very well be that my power connection arrangement was the culrpit of the blown ESD chip rather than the PC PSU. Since I am only partially familiar with the internals of the NOS1, it is hard to reason how such a thing could happen and wether it happened to you.

Regards, Coen

Hi Mani,


This sounds awfully familiar. I had a similar experice some time ago, but I never changed the stock USB cable. I could hear everything from the pc, mouse, hdd, cpu with distinct noise patterns. Annoyingly loud with horns. Afaik i toyed around with pc powercables (with/without PE connected, different powerstrips) and with the cabling in my amp. It is solved but not by usb but either by amp rewiring or powercable optimisation or new power supply(?). Have to remember a lttle harder how I did it...

Afaik the usb powerwire isn't connected to anything in the NOS1, except maybe the spike protection chip at the input of the USB. I'm not shure about that, but if correct noise from there can enter the circuitry.

I've been studying the Berning a couple of years ago. A very interesting, very, very clever design. But you have to realise it works like an AM  radio with the output transformer as sending and receiving antenna. The whole high voltage is modulated at a high frequency at the 300B side. Allways wondered how this works out for RF.

Regards, Coen

Just got some more ramblings in my fingertips...

I realise I forgot one important thing and that is the whole point of earth referencing is to NOT have currents flow through them that are generated by the circuitry; it is just creating a "silent" point for your circuit towards all other voltages are referenced. they don't change their relative values. It is what it is: a reference. This is where the refrencing the usb at two points goes astray: the groundrefs 2 and 3 are able to and will carry a signal.

Than there is the matter of radio energy that has a potential to the earth and as such can induce currents in conducting objects (wires, casings etc) to earth, closing the loop from the antenna to ground. So here the ground ref has a completely different function: getting the radio energy out of the circuit (or let it stay in the box... ). For this you only have to ground the casing that contains of the circuitry.

So my common sense says: or wire 1 or wire 2, no 3 and no connection between the case and circuit of the poweramp would be optimal.

Regards, Coen

John S also talks about the groundplanes being polluted by circuit noise. This means that you have to choose a quietest point on your grounding where you connect the earth reference. If you make multiple refs on the ground you create the possibility to run currents through the ref (aka loops) especially when this is a low impedance path for the noise involved.
So if the pc is refecenced to ground at a certain point and you add another ground reference at the usb terminal you have two referencepoints. My point is that the effects of this are now rather unpreditcable.
I would rather experiment what the difference is between referencing at the pc ground at the plug versus referencing at the usb side.

Since the NOS1 circuitry is internally "floating" I would expect that it is not adviced to ground the poweramp circuitry. You will create a path for currents to pass through the NOS1 (that is that a low impedance path is via the NOS1).

I realise this need more thinking and experimenting.

Regards, Coen

You not only referenced to the earth rod but also ceated a new path for currents. Current runs in loops like from pc to dac via 2 and 3 (and back through the usb cable) or via 2 and 1. Etc etc.

Like stiffness in mechanics, the current (like displacement) will yield toward the least resistive (most stiff) path.

And then we have induction: the wires acting as a current generators within ac fields.

Currents all over the place. Some for the better, others for the worse. This is trial, error and learn material.

Maybe a bright guy is able to solve this puzzle... Peter? Anyone?

Regards, Coen

Loudspeaker filtercoils pick up a lot of stuff. Once I disconnected the amplifiersignal to the filtersection of one driver (you can do that with biwiring). Still music was playing though that driver at a low but hearable level. It turned out to be the coils of the filter coupling with eachother. With a relocation and repositioning I could attain silence. I was surprised how much apart they had to be even with orthogonal axes.
This is very noicable with efficient horns of course.

Plus I can make disconnected speakers hum by just touching the loose wires.

Regards, Coen