Computer audio discussion

[brombo]

Another and probably more affordable linear pc power supply -

http://www.hd-plex.com/HDPLEX-Fanless-2 ... evice.html

[charliewphelps@gmail.com]

For what it's worth I'm using the HDPlex supply. Made a tremendous difference. I always hate it when something like this makes a difference. Just not supposed to happen.

Charlie

[Cogito]

Charlie,

Which distro of Linux are using?

Couple of people on the suggested the quality PS in the PC reduces jitter, i.e., more time-perfect streams, which makes sense. The power supplies that come with computers is very poor quality. The concept behind "Real-time" distros like Snakeoil and AP-Linux Is reduction of jitter. Wonder if a quality switching PS with RT Linux would yield the same results.

Number of years ago when I was building my own PCs, always used oversized PSs by a factor of at least 2, to protect the PC components from surges.

[DaveR]

Jitter is not an issue with USB, the clock is part of the data stream. The USB clock is not involved with the data being converted to audio.

[Cogito]

Jitter is not an issue with USB, the clock is part of the data stream. The USB clock is not involved with the data being converted to audio.

You are assuming three things:
1. Entire Music file is sent to DAC in a single contiguous and uninterrupted stream.
2. USB clock is perfect
and
3. Clock synchronization always works perfectly.

[DaveR]

I'm not assuming your first two points.

This is a fact: USB data is self clocking. Every bit of data contains the clock required to clock it into the receiving buffer. The USB clock does not have to be terribly accurate or precise by design.

Because of that fact, USB clock synchronization does work perfectly. USB did not invent Manchester coding, it's just taking advantage of it.

[Grover Gardner]

I'm not assuming your first two points.

This is a fact: USB data is self clocking. Every bit of data contains the clock required to clock it into the receiving buffer. The USB clock does not have to be terribly accurate or precise by design.

Because of that fact, USB clock synchronization does work perfectly. USB did not invent Manchester coding, it's just taking advantage of it.

Gordon Rankin, who basically invented asynchronous USB, claims there are other sources of jitter, and that implementation makes a difference.

Asynchronous USB data transfer however doesn’t automatically guarantee perfect sound. J. Gordon Ranking informed me of the following: “Many of the less expensive units do not use a fixed oscillator and instead use a frequency synthesizer and therefore have worse jitter than a dedicated fixed oscillator. Many companies don’t even know how to power fixed oscillators. If you go to say Crystek and ask for a really good oscillator and then power it with a 3 terminal regulator the results will be less than staggering. For high end you need a discrete regulator with ultra low noise to establish a really good low jitter Master Clock.”

Scroll through the product peddling in this article to read some of his comments:

http://www.digitalaudioreview.net/2016/ ... ty-varies/

[brombo]

Can anyone here make a comparison between an usb dac and an hdmi dac with regard to relevant characteristics. Again, my Emotiva UMC-200 preamp with hdmi inputs has a direct mode where all other dsp processing is turned off and it operates purely as a dac with analog master volume control and analog trim controls for each channel. I ask this because I am considering using Jriver to implement a dsp crossover and using the Emotiva purely as a dac.

[Cogito]

LPS:
Does the laptop running on a battery sound better then running in walwart?

Interesting to test.

[Grover Gardner]

LPS:
Does the laptop running on a battery sound better then running in walwart?

Interesting to test.

Depends. Batteries have their own issues and can be noisier than switching supplies. You might get lower noise and you might not.