Charles - Most devices that deliver low jitter are buffering either packets over the ethernet or WiFi or they are buffering bursts over USB from a computer. The data is then clocked out of these buffers with a free-running clock. The latter is mor like a stream, but it is still bursty.
In the early days of computer audio uninterrupted streams did exist, but these were clocked from the computer as master and it was difficult to achieve low jitter using these protocols. These methods have been all but abandoned.
Steve N.
Empirical Audio |
"it sounds like congested chaos, has a rough texture (especially noticeable in voices)and overall is just very brash sounding."
Two things are likely causing this:
1) too much audible jitter in your digital source - typical for rough textured vocals
2) FLAC files - typical for listening through a cave effect
#1 can be fixed by upgrading your USB converter and using a better power supply and S/PDIF coax cable for it
#2 is more difficult. You either have to be willing to live with .wav files and minimal tags or get a server like the Antipodes that sounds identical with both. Another option is to try JPLAY in conjunction with Jriver. This may or may not help.
Jitter numbers are all but useless when they get to these levels. The problem is that jitter like most phenomena is not something that occurs in one instance or repeats the same every time. There are billions of instances and each one is different. This creates a Gaussian distribution of jitter events that can be examined. Some of the jitter events may be data correlated and others may be random. When one says that a particular device has 500psec of P-P jitter, this is incomplete information because the 500Psec event may only occur every 30 seconds, or it may occur every millisecond. Big difference in these two. Also, the shape of the peak of the distribution may be very narrow in one case and very wide in the other. In other words, the distribution of the jitter events must be studied in order to determine whether one device is actually better than another. Then of course, one must listen to music as well. The human ear is the only thing that will tell you definitively whether one jitter distribution will sound better than another.
I would recommend upgrading the USB converter first, as well as an upgrade power supply and Coax cable. Most of these have money-back guarantees, so your risk is low.
Steve N.
Empirical Audio |
It is possible to match or even beat your vinyl with the RIGHT digital:
www.audiocircle.com/index.php?topic=95464.msg960567#msg960567
www.audiocircle.com/index.php?topic=105049.msg1159717#msg1159717
forum.audiogon.com/cgi-bin/fr.pl?icomp&1351958193&openusid&zzErndog&4&5#Erndog
Steve N.
Empirical Audio |
Megido - another thing that can prevent you from hearing the difference between .wav and FLAC is the active preamp. Most people use one and it's not a $15K one. Eliminating this in favor of a good DAC volume or a transformer linestage makes a big difference. Eliminating ground-loops in the system also helps a lot.
Steve N.
Empirical Audio |
Cerrot - Based on this post you do not know much about the technical aspects of USB. A PCI card and a USB interface can perform equally well from the S/PDIF output based on the design and implementation of each and the supporting power systems.
Steve N.
Empirical Audio |
"As I understand it though, If s/pdif is being used on a source that already has high jitter, it will do nothing to reduce that jitter. It just wont add any more, at least not on the level usb would. I can't imagine a computer being a low jitter environment."
Actually most modern S/PDIF receivers reduce jitter a bit when regenerating the clocks for I2S to drive the D/A chip.
Async USB on the other hand generates a new master clock and ignores the clock from the computer, therefore the jitter on the USB cable is of no consequence. It is ignored. This is because the Async USB interface is the MASTER and asks the computer for data packets only when needed. These packets are put into a buffer, which is clocked out using the local free-running low-jitter Master Clock.
Steve N.
Empirical Audio |
Megida has little to lose here. Most of these reclocking and USB converters have money-back guarantees. If it does not wow you, send it back.
I guarantee my products will wow you, or there is something else seriously wrong with your system.
Steve N.
Empirical Audio |
"Does anyone know if jitter can be introduced in the recording process? If so, is there a way to deal with it?"
Absolutely. No way to fix it once the recording is made.
Steve N.
Empirical Audio |
USB stands for UNIVERSAL serial bus. There hundreds of DACs with USB input, some with USB output, lots of USB converters and more and more music servers with USB out. Get educated. |
"I have to confess that Cerrot makes an interesting case, is this convenience/ universal use(USB) vs ultimate sound quality(SPDIF sound card)?"
Absolutely not. Nothing to do with convenience. Has more to do with choosing among the various protocols available. Only Firewire, Ethernet and USB were options. USB makes perfect sense. Nothing wrong with the protocol. In fact is is actually superior to Ethernet in some ways: the connection is isochronous. Ethernet is never isochronous. This means that the stream cannot be interrupted by other message traffic on USB, only on Ethernet.
You must understand here that Cerrot has not had a positive experience with USB and has had with PCI bus, so he believes that USB is inferior for this reason. There are no technical arguments that he has made that hold water.
On the other hand, I can make lots of technical arguments why PCI is a bad idea for music streaming. The first being that it is in close proximity to the CPU and clocks that all radiate emissions inside the computer chassis. IT is also sharing a DC power supply or transformer/switcher rather than having its own separate power subsystem. This is why even the best PCI based systems can get positive mentions at shows, but usually do not get best of show like the USB based systems do.
Steve N.
Empirical Audio |
"I have to admit the Juli@ intrigues me because it has a clock input. As my DAC has a clock output it might be possible for me to slave the card to my DAC."
Another reason that this is not a good choice. In order to "slave" a clock like this, the clock must be a PLL, not a free-running clock. PLL clocks NEVER EVER have the low jitter that a free-running clock can achieve. The Lynx is another case. Used it. Been there, done that.
If you have a DAC with a good master clock in it or a way to get word-clock out of a USB converter, such as the Off-Ramp, then the clock in the PCI card is no longer of any consequence. The master clock can be in the converter or DAC, not the PCIU card. For these systems the cards can be useful.
Steve N.
Empirical Audio |
Charles - you can get the Off-Ramp 5 as well (as the Dynamo power supply to power it) for 30 days, money-back, less shipping. It will crush any PCI card.
Does the PCI card have money-back guarantee?
Steve N.
Empirical Audio |
"So re-clocking the digital signal from the S/PDIF vs a USB converter, would there be an advantage to one over the other?"
Yes. Both are establishing a new Master Clock, but the reclocker must resample the data. There are minor artifacts with doing this. Even the best resampling hardware is not perfect. The USB interface on the other hand does not resample. It does not change the data at all, making it superior with better SQ.
Both are excellent however, particularly when powered from my new Dynamo power supply. The difference is actually small.
Steve N.
Empirical Audio |
Granny - I actually already have customers using the OR5 with the Lampzator, as well as many other USB DACs, including EMM Labs and AR.
Its a simple matter to order one and try it. If it doesn't make a huge difference then send it back for refund, less shipping.
I would recommend in order to get the full performance from it, order it with my BNC-BNC coax cable with RCA adapters and my Dynamo power supply. At a minimum get the OR5 with S/PDIF Hynes option.
Steve N.
Empirical Audio |
