Tír Na HiFi

Sligolad wrote:On the subject of Ankers!
I set one up on the SSD running server core on the Zuma audio PC today and it has made a good improvement as predicted.
Runs continuous without anything else connected.
What was telling is that I ended up switching off my sub today for the first time since it has been in my system after running with the Anker 5v supply to the SSD.
Really good bottom end now and the Quads are well able to deliver without the sub so looks like the B&W is finally going in to retirement.

Spent about 5 hours just listening to music so did not get to wire in the 12v to the CPCU, maybe tomorrow.

Sligolad wrote:On the subject of Ankers!
I set one up on the SSD running server core on the Zuma audio PC today and it has made a good improvement as predicted.
Runs continuous without anything else connected.
What was telling is that I ended up switching off my sub today for the first time since it has been in my system after running with the Anker 5v supply to the SSD.
Really good bottom end now and the Quads are well able to deliver without the sub so looks like the B&W is finally going in to retirement.

Spent about 5 hours just listening to music so did not get to wire in the 12v to the CPCU, maybe tomorrow.

tony wrote:

Sligolad wrote:On the subject of Ankers!
I set one up on the SSD running server core on the Zuma audio PC today and it has made a good improvement as predicted.
Runs continuous without anything else connected.
What was telling is that I ended up switching off my sub today for the first time since it has been in my system after running with the Anker 5v supply to the SSD.
Really good bottom end now and the Quads are well able to deliver without the sub so looks like the B&W is finally going in to retirement.

Spent about 5 hours just listening to music so did not get to wire in the 12v to the CPCU, maybe tomorrow.

That is more good news. We can now proceed with the swap of your black B&W PV sub for my silver one.
Win win for both of us.Silver or grey is a much more suitable colour for retirement.

jkeny wrote:BTW, for cheaper CPU options there are Haswell Pentium CPUs - cheaper than i3 Haswell apparently?
http://www.cpu-world.com/news_2013/2013 ... faced.html

""Haswell" CPUs come with identical frequencies and other major features as Ivy Bridge-based G2030, G2030T, G2130, G2120T and G2140. New Pentiums have 2 CPU cores with 3 MB of last level cache, Haswell HD graphics, 35 Watt TDP on "T" products and 54 Watt TDP on mainstream products. The parts integrate basic set of technologies, including Intel 64 and Virtualization, but lack more advanced features, such as AES, Hyper-Threading, and Turbo boost. Despite almost identical features, Haswell Pentiums are expected to be faster than current G20xx and G21xx series microprocessors due to more efficient microarchitecture and enhanced GPU. We can only hope that Intel will not raise their prices by small margin, like they did with 4th generation Core i5 and i7 CPUs."

Might be more suited to audio use as graphics is lower specced & we don't need turbo boost or hyperthreading, I imagine? So could be a win-win solution. Same TDP as i3 so passive cooling is still an option

DaveF wrote:I havent read the entire thread as I've been away from hifi for several months but is the motivation behind this dedicated PC that you'll minimise or eliminate all sources of ground noise that might otherwise pollute the USB connection down to the DAC?

I take it that belief is that the bits extracted/packaged by the PC and sent to the external DAC are always the same no matter what PC improvements or JPlay versions are in use? That the technical explaination for any real improvements is the above?

DaveF wrote:I havent read the entire thread as I've been away from hifi for several months but is the motivation behind this dedicated PC that you'll minimise or eliminate all sources of ground noise that might otherwise pollute the USB connection down to the DAC?

I take it that belief is that the bits extracted/packaged by the PC and sent to the external DAC are always the same no matter what PC improvements or JPlay versions are in use? That the technical explaination for any real improvements is the above?

So now the crux of the matter, how can what goes into the USB receiver affect any of this? In several ways: packet jitter, edge jitter, PLLs. I’ll go over each of these.

Packet jitter is the difference in the arrival time of packets to the receiver chip. USB packets are transmitted over the bus at either 1000 per second (full speed mode) or 8000 per second (high speed mode). Every time one of those packets hits the receiver a lot of activity happens inside the receiver chip. This creates lots of noise inside the chip and on the ground plane. This causes a lot of jitter on the outputs from the chip. The spectrum of this noise and jitter has a VERY strong component at either 1KHz or 8KHz, both of which are directly in the audio range. Any changes in the arrival time of the packets will change the spectrum of this packet noise. In the next installment I’ll cover what causes this packet jitter.

Next is edge jitter, this is traditional jitter of the individual edges on the bus. As with everything else I have been talking about, jitter on the input can cause noise in the chip and on the ground plane that is related to the spectrum of the jitter. This is where things like different cables can have an effect on what is happening.

Next is PLLs. Every USB receiver chip has at least one if not more PLLs. These PLLs are affected by both the previous types of jitter and since almost all the circuitry inside the chip is clocked by these PLLs, the jitter on output signals and ground plane noise is going to be significantly affected by the noise spectrum coming out of the PLLs. This is filtered by the PLL loop filter, but there are still major components related to the input jitter.