Hello, Petr. Not off topic at all.
I do not own the amplifier, but I looked at their manual online and the eHam discussion.
I would be careful about buying the amplifier unless you get more information regarding QSK.
I would assume it is set up for PTT operation which is fine for SSB, but not for QSK QRQ. To get good
QSK you need a diode or relay based setup and for solid state amps especially you need to be very careful about hot switching. I would do a bit more research before buying the amplifier for QSK unless you are willing to design a QSK system for the amplifier on your own.
I am not an engineer but learned a lot about QSK from guys on this website while getting my old Omni D and Ameritron AL.811H working with a relay based QSK system.
I hope we get more comments.