I have recently bought a Sony PCM D50 to replace my aging "Net MD" for portable recordings. I shall continue to use my existing Sony ECM-957 mic with the new .wav recorder, but have noticed the mic performance is affected if the D50's "Plug In Power" is selected to ON. This makes the mic less sensitive and the lower frequency response is very attenuated. Has anyone else found this, or does my D50 perhaps have a preamp issue?

There is no mention in the D50 manual warning this can happen and that "Plug In Power" should be selected to OFF for self powered condenser mics.

(The Sony "Net MD" has "Plug In Power" permanently on but the ECM-957 is unaffected by it. Perhaps the D50 puts put a high voltage, but it shouldn't affect the mic operation in my opinion.)