I went to the web site you listed and took a look at the information provided. What I found was a mixed bag of good engineering and marketing claims. The points made about SRCs and their inability to reduce jitter (they actually increase it) were correct. What seems somewhat dubious is the claim that their device reduces jitter in any meaningful way. From what I was able to extract, they appear to be improving the S/N ratio of the bi-phase stream. While this may be useful in some circumstances, it is not directly reducing the jitter component caused by the sample clock. It is possible that these devices might be of some value when used with some D/A systems, their claim about A/D applications is completely off base. A much better approach would be to use an interface that does not rely upon the quality of the "recovered" clock, but transports the clock as a separate data path (or even better supplies it from the converter to the transport, like Universal I2S or MAP-Link). Assuming that you all the following are true, then you might want to consider the product. 1) Your purchase is conditional, meaning that you have the opportunity to recover your investment based upon the outcome in your system. 2) You are able to set aside any preconceived notions about the outcome of the test. This is not easy, for even if you experience a genuine change, the tendency is to label something "better" even though it may only be different. 3) You can conduct a "single blind" test. Ask some disinterested party to insert and remove the device from the signal chain on a number of different days. Have your system configured in such a way as to assure that you cannot know about the devices presence or absence. Be certain to use whole days and not shorter periods of time. Compare your observations after 4 or 5 days of testing to the reality of the devices presence. If you have accurately identified the presence of the device, then you can safely state that your system and methodology are acceptable for establishing this device in your application. If, after all the above, you find that you can accurately identify the device in the chain, and you feel that you are experiencing an improvement, then by all means use it. If not, then save your money. Kevin Halverson
