With the latest release of sc_trans v2, there appears to be a bug (referenced here) causing low bitrate AAC streams to the DJ Port to be badly sampled.
There are two resolutions for this:
a) Stream to the DJ Port at 96Kbps AAC. sc_trans will automatically and properly resample the stream to your output and this sounds great.
b) Replace the [MediaCP]/files/sctransv2 binary with sc_trans Build 40. Please note, this version is no longer supported by Shoutcast/Winamp.