The National League North newcomers snapped up the goalscoring 24-year-old from Whitby Town for an undisclosed fee last week, albeit for slightly more than they'd have liked.
Hobson finished third in the Evo-Stik Premier goal charts last season and was unsurprisingly on the radar of many clubs this summer.
With this signing, Blyth have laid down a marker for the new season and Armstrong told the club's website: “He scored over 30 goals in all competitions last season and he’s someone I was definitely watching. We knew he was dangerous and we haven’t really got a player like that as such.
“It’s cost a lot more than I’d have wanted to pay, to be totally honest, but that’s the current market and it appears to have taken off for some reason. For someone of his ability though, you have to pay to the money.
“The biggest thing for me is that he scored nine out of nine penalties last season, whereas we pretty much missed nine out of nine penalties!”
Hopson added: “Obviously, pre-season is already underway [but]I’m looking forward to getting started properly with the games. It’s a big club and a big step up for me from Whitby, so I can’t wait to get started.
“I think – from a playing point of view – when I spoke to Alun, I seemed to get the satisfaction that I needed [to sign for Blyth]from talking to him. I’m glad it’s all done and dusted now really.”