Santa Barbara-based wireless music gear maker Sonos has raised $135 million in new capital, the largest funding deal in the Tri-Counties so far this year and a possible step toward a future initial public offering.

Kohlberg Kravis Roberts, a private equity firm, led the funding round and was joined by Redpoint Ventures and investors associated with Elevation Partners.

Sources confirmed to the Business Times that $45 million of the new round is primary capital that will be used to grow the company and that the remaining $90 million will be used to buy stock from founders and earlier investors. Such moves sometimes precede a public offering.

Those previous investors include Index Ventures, which led a $25 million round in 2010, and BV Capital. As part of the deal, BV Capital partner Andreas von Blottnitz will leave the board. Von Blottnitz was CEO of Santa Barbara-based ExpertCity when it sold to Citrix Online and has remained an active investor in the Tri-Counties, where he has funded firms such as AppFolio, whose board he sits on.

David Kerko of KKR will take a seat on the Sonos board as will Fred Anderson, one of Elevation’s partners who was formerly the chief financial officer for Apple.

Sources confirmed that South Coast entrepreneur John MacFarlane, the CEO of Sonos and former mastermind of Software.com, will remain at the helm.

Sonos makes a wireless digital music player that can beam 32 different streams of music to rooms in a home or business. Though the firm keeps a quiet presence on the South Coast, the high-end gear has become increasingly popular with the rise of streaming music services and is reportedly gaining traction in Asia and other markets.