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CPU and DAC settings.
"The NOS1 can be used by any software player to good effect if the filtering called 'upsampling' is engaged. Here again our proprietary Arc Prediction filter as created especially for this DAC comes into play. This explains why it takes 768kHz input sample rates even though no music files employ them. That's the output sample rate of the software filter." Jitter is the greatest enemy of digital audio and the two NOS1 clocks for 44.1 and 48KHz-based data have a jitter specs of <0.2ps. More impressive figures come from an S/N ratio of -132dBFS at 0dBFS on the XLR output. On RCA that's -140dBFS at -6dBFS. Total harmonic distortion for 16/24-bit inputs with a 192kHz signal is 0.0018% on RCA and 0.0015% on XLR. Peter states that a 768kHz signal should theoretically generate THD+N of 0.00045% for RCA and 0.000375% for XLR. Yes there are three zeros behind those decimal points and Peter emphasizes that these figures are for 16-bit inputs. That's admittedly theoretical math as available measuring gear won't resolve at these depth. Channel separation has been measured at >125dB for RCA and >130dB for XLR. According to Peter it is noteworthy that these astonishing figures arise with a zero-ringing filter to imply utter time domain accuracy. This demanded listening.


Most peculiar in audiophile circles is Peter's explicit advice to only use his el-cheapo USB cable dispatched when he delivered his DAC. He designed, measured and tuned everything around this €1 leash. Benefits from exotic cables are not due to any cable but cover up something wrong elsewhere he states. In the same vein Peter believes that noise does not ride beneath but atop the signal. Over dinner our conversation revolved around audio but also the Stordiau family’s other passion: food and wine. From there it was a small step to computer-related products at our discount ALDI markets. Another subject was the efficacy of all manner of audiophile add-ons, in particular Franck Tchang's ASI Sugar Cubes. Peter did not believe they could possibly work until a few days later when he reluctantly experimented with some similar devices. This caused him the usual headache but also proved to him that something was in fact at work. Now he actually advises to experiment with footers under his DAC.

At this point we had a PC running on Vista and XXHighEnd with the appropriate Phasure DAC driver together with a stack of EAC-ripped WAV files. From that PC the very flimsy USB cable ran into the NOS1. Before we forget, asynchronous transfer protocol implies that the DAC runs its own clock and via a feedback loop controls the computer's output stream. A cheap cord connected the DAC to the power grid. It should be no surprise that in Mr. Stordiau’s universe such a cable should plug straight into the wall sans any conditioner or regenerator. Finally the NOS1 was leashed up with pro-arena interconnects to our Ncore 1200 monos and Avantgarde Duo Omega hornspeakers.
Cover art settings.

What followed was a lengthy period of attempting to get the best from the system without achieving either stability or the promised sound quality. One of the culprits no doubt was our aging PC running ancient Vista. With only a single CPU, processing power was not on par with the demands of Peter's advanced playback software. It was time to ask for help in the hardware department.

This began with our question about just what type of computer would prove ideal to run XXHighEnd. It ended with us commissioning Peter to put together our ultimate music computer. This steered him into a completely new direction of personal computer hardware dealer. The prerequisites for such a dream machine were high CPU speed, large memory, fast I/O channels, stable power supplies and very silent operation. It took a few weeks until Peter announced his arrival with the awaited computer.
On-screen displays and services to be kept running.
From his box emerged an audiophile-black SilverStone HTPC silent casing with an Intel Core I7-3930K CPU running at 3.2GHz sporting 6 cores and 12 logic processors with 16GB of RAM. 64-bit Windows 7 Ultimate SP1 sat on a 150GB internal disk home also to XXHighEnd. An additional 500GB internal disk has h converted tracks copied to it. A removable 56GB SSD completes the internal storage. On Peter's advice we picked up a few 2TB USB3 external hard drives from ALDI for music storage and backup purposes. A PS2 keyboard and mouse (no USB which would cause noise) plus basic LG Flatron LCD monitor completed the rig. Now the fun could begin. We started off with the default settings of XXHighEnd to become familiar. We ticked boxes for unattended playback, selected the Phasure NOS1 DAC with the appropriate device buffer size of 4096, set 15ms clock resolution, turned on the kernel streaming #4 engine with core scheme 3, low player priority and real time threads, the SFS size of music chunks loaded to memory at 0.2 each and memory alignment as straight contiguous to work glitch-free.