Originally Posted by IPodPJ
But how do you know it's a high jitter source unless you measure it???? And how do you know what comes out of your Pace Car is very low jitter when you don't have the tools to measure that either??? You are making no sense.
There is a simple way you could infer the effect of a jitter-reducing device, it would not be amazingly accurate but it would give you a general idea.
You rip a CD track and verify that it is a bit-perfect rip, this is your reference point.
Load up the track on your digital device sans jitter-reducer and play back the track and record the analog output using a decent say 24 bit ADC, compare the reference with the recording, they will not be the same. Adjust the recording level until you get the recording as close to the reference as possible, it need not be perfect. Then repeat 10 times to allow for random variation.
Add the jitter-reducer to the circuit and again repeat the calibration recording and the 10 actual recordings.
Load the samples into an audio program and scope out the FR for each of the 20 samples. Export the FR data to Excel. Average the results for each combination. Then chart the final data as a line chart. Zoom to 1600% and see if you can see any differences. You can of course then do the maths and quantify any differences.
It is crude but if there are any differences that are bigger than the incipient error, and a good 24 bit ADC should give you 19 - 20 bits accuracy or about 1 - 2 parts per million, you will see them. If the differences are below the 19/20 bit accuracy I really would not lose sleep over them
You could even blind test the most typical sample from each set .
If Steve N. wants to lend me a pace-car I have several digital devices with optical outs that should be quite high in jitter such as a Western Digital HDTV and a Marantz CC4300 that bothg feed my Entech 203.2 .