We did have one just for YTtalkTV but then I realised maintaining both that and the proper YTtalk page was a bit OTT, the same with maintaining two Google+ pages, these days I use the YTtalk Facebook page for both YTtalk and the channel. I made the page for YTtalk almost right away and the same with the YTtalkTV page when the channel was created. There is no harm preparing and making things early on and it can also protect your brand by taking your username before someone else does intentionally or not.