Al - First, I agree that proper setup of the PC is necessary, including not letting the CPU performance fluctuate, as you point out. I should have added the caveat the the PC is well set up, which I agree is not always the case.
I agree that there is a potential for noise issues without isolation. That is why various isolation technics are being used. Any extra noise should not affect the left/right data bits. The amount of processing used to decode a FLAC file is really minimal. I just do not see that minor extra processing having much effect. When I compare playing WAV files to playing FLAC files I do not see any noticible fluctuation in CPU usage. It must be there, but it is pretty minimal, at least on my system., where usage is typically under 5%. As I said, if the async USB is doing what is advertised to do, then that noise should not affect the timing. If the noise interferes with the async USB circuits in the converter, then differences are certainly possible due to jitter. So fair enough, it is possible. I am just not sure there is enough noise from unpacking the flac to make an audible difference.
It seems that people using wireless solutions would not see the effects of this noise, unless it goes through the power cords.
I must say, it would be very difficult to actually measure any of these differences on the circuitry of the converters and DACs.
The 35 pound Hubbard squash is cooking. The French Canadian meat pies (Tourtier)are getting started, and the traditional home made vegetable soup for Thanksgiving lunch is just getting going, although we made the stock yesterday. Starting to smell good.
I agree that there is a potential for noise issues without isolation. That is why various isolation technics are being used. Any extra noise should not affect the left/right data bits. The amount of processing used to decode a FLAC file is really minimal. I just do not see that minor extra processing having much effect. When I compare playing WAV files to playing FLAC files I do not see any noticible fluctuation in CPU usage. It must be there, but it is pretty minimal, at least on my system., where usage is typically under 5%. As I said, if the async USB is doing what is advertised to do, then that noise should not affect the timing. If the noise interferes with the async USB circuits in the converter, then differences are certainly possible due to jitter. So fair enough, it is possible. I am just not sure there is enough noise from unpacking the flac to make an audible difference.
It seems that people using wireless solutions would not see the effects of this noise, unless it goes through the power cords.
I must say, it would be very difficult to actually measure any of these differences on the circuitry of the converters and DACs.
The 35 pound Hubbard squash is cooking. The French Canadian meat pies (Tourtier)are getting started, and the traditional home made vegetable soup for Thanksgiving lunch is just getting going, although we made the stock yesterday. Starting to smell good.