Quality Problems converting mp2 128 kbs 48 Khz to mp3

[Tilman]

I have the problem that after a conversion from mp2 128 kbs 48khz from a marantz prof. solid state recorder to any mp3 format 44.1 khz the file produces a level dependent humming sound when played in winamp 5.03 when playing that file in MS Mediaplayer the file it sounds correct.
The humming effect is audible but not massive. It is like a slight amplidude modulation of the whole soundfile.
If I do the conversion wiht another tool like mp3doctor the file sounds ok in winamp.
So my conclusion is, that it must have to do something with goldwave or how goldwave resamples the mp2 file to an mp3 file.
I also tried mp2 -> wav -> mp3 but still the same effect.

Is there anybody who has a suggestion why this happens?

best regards Tilman

[GoldWave Inc.]

Does the problem occur if you use 48 kHz MP3 attributes instead of 44.1 kHz? Also try using a Lowpass filter effect with a cutoff of 18 kHz before saving as MP3.

Chris