NOS1a : A new "tweak"

[CoenP]

Is that 11VAC stable ? I mean, can you notice that it changes by means of *other* apparatus being switched on/off ? Like your million phone chargers, dishwasher, lights, beer tap ...

I've pulled some chargers and lamps, no fridges, pumps or washing machines (yet). I did not notice a difference. Mind you that both amp and nos have in my case no PE connected. (both float wrt earth)

Peter and Nik, to be really specific about the word "chassis", I actually measured between the signal grounds (outsides of rca connector) of the devices. Imho this is in my case the best/only way to assess how the devices float wrt each other.

Regards, Coen

[CoenP]

And for PCI card isolation: did anyone really tested isolation? 'Cause (my case at least) as soon as card is put in slot
or molex connector is in, there is connection PCI card (gnd plane) - PC chassis. As if card's bracket is normally fitted & bolted.

Full isolation is complex, you'll need separate supplies and adequate high voltage decoupling. The NOS1a already has that.

My take is that there is a major difference in ground path that affects the voltage differential between the PC and DaC (which has an effect on the total differential between DAC an amplifier). I presume that this will be more important now since noise is less of a issue.  With the mounting plate isolated or removed the chassis will as you say be connected to the USB ground via the PCIe motherboard connection and power supplies. When connected the USB ground will stabilize around the chassis potential rather than via the more resistive path of the PCIe...

Regards, Coen

[CoenP]

Since I found a couple of cables in the box and connected them in the last days I have come up with some first impressions. I played a variety of music with 1.186i on Win7.

- 1 m audio grade usb2 cable: thick congested sound, no refinement. This cable does well on my Ifi nano though.

- Standard 1,5 m Phasure Usb2: nice balanced and refined sound.

- 5m ICIDU packaged usb2: not much different from the 1,5 m std cable. If anything I think it sounds a little softer/gentler on the ear. This is the newest cable.

Short listening on win8 did not alter abovementioned observations.

I have some shorter cables (50cm) but I could not manage to make adequate contact as also the 1,5m USB3 male-female extension cord refused to work properly. No luck with usb a to usb b adapters either. Result: No phasure driver or a lousy contact with a lot of errors.

The 5m is vey practical so if i still like it next week it stays in.

Regards, Coen