Question about Goal Zero Yeti 400

The Yeti 400 has a true sine wave inverter and should therefore not interfere with 230V electronic devices. The sine wave looks very good on the KO. Whether and at what quality of the connected audio devices a humming noise is to be heard, however, cannot be predicted with 100% certainty and would have to be tested 1:1 with the corresponding device combination. With a master keyboard (Ketron SD7), there is no difference in my case compared to a normal socket. However, humming noises in audio amplifiers can have various causes, e.g. a humming loop due to a circuit in an audio ground connection parallel to an earth connection of the protective earth in the 230V supply of the components.

I am not a musician but I still heard the Yeti. We took it to an alpine hut without electricity and light and I assume that we would have heard any humming in this silence. It's a top product from my point of view.