External speaker for Z50

Several of our users are having trouble hearing the internal speaker(s) on their Z50s. We've tried some external speakers and ear buds, but they all have a VERY noticeable hissing sound in the background.

This appears to come from the thin client itself. It happens even when there are no RDS or ICA connections.

We recently upgraded from T10s and the T10s had no problems using external speakers.