Question about rigol DG1022 function generator

[JerryG]

I just bought a new rigol DG1022 function generator and I noticed that when I turn the voltage higher than 2V peak to peak, the FG emits a faint high pitched sound. It's barely audible; maybe around 15 kHz. Is that normal for a digital function generator, or does that mean that something is wrong with it? Oh, and the pitch of the sound does not vary with the output frequency.

 

[EWH]

Maybe just hearing hysteresis in the transformer of the switching power supply? Those are often run at high frequencies. If nothing is getting too hot and the output waveforms are still correct at the rated load, I wouldn't worry about it.