The firm said it would send out 300 prototype Steam Machines, which are designed for use in the living room.
The company added that other manufacturers would begin selling devices running its games-focused operating system SteamOS next year.
The move was described as “audacious” by one analyst, but another had doubts about who would buy the devices.
Console makers – including Sony, Nintendo and Microsoft – typically do not let the public take hold of their hardware until it is ready for release.
Valve currently offers its Steam platform as software running on others’ systems – Microsoft’s Windows, Apple’s Mac OS, Sony’s PlayStation 3 and various Linux-based software. It acts as a marketplace and a way for gamers to play against each other and share titles.
Valve uses Steam to promote its own games – including Half Life, Portal, and Dota 2 – as well as those written by third-party developers, from whom it takes a cut of the sales.
It does not release sales statistics – but estimates from consultancy IHS Screen Digest suggest Steam is responsible for 75% of PC game sales, bringing in about $1bn (