It sounds like the first pop when you put the needle down... Same sound and same length, maybe 1/4 of a second.

The dealers 3200's, 5200SE and 7200SE don't do it...

It happens whenever an audio signal starts or stops, or when changing volume, not just when changing file type. It doesn't happen when one track rolls on to another in the same album because the audio stream is continuous.

Finally the proud owner of a 218 and 3200's... Will they grow up to be an 818v3 and 8000 se's???
Isotek Sigma Evo 3 power conditioner