I agree with Fourth Wall Games. My main channel is heavily focused on Game Development. When I got into making Music, I decided to make a new channel to post music because I didn't wanna mix everything together. I felt it would look cluttered.
I started my channel with the idea of the channel being about me as the topic. Most of my videos would be gaming videos but will be uploading vlogs and other things that I wanted to share as interests of mine on an occasional bases.
As a small channel you don't want to be spreading out your fan base. If it's totally different content then maybe use 2 channels but only if your prepared to manage 2.