Can I use a different amp head with amp combo?

[Soulnsync]

I was wondering if I can use a tube amp (Bugera 550W Valve Bass Amplifier Head) with the amp combo speaker and just unplug from origianl amp head and connect to the new. Is it as easy as it looks? is it safe? or should I just wait to buy a bigger cabinet, which I will eventually, when I can afford the one I really want. Could this work in the interim? See pics

Thank you,