UPDATE 1-Kabel Deutschland raises $750 million

* Lifts volume of new loan to $750 mln from $500 mln

* Says changed volume due to investor demand

* Seeks to extend existing loans by three years

FRANKFURT, Jan 23 (Reuters) - Loss-making Kabel Deutschland (KDG) said it raised $750 million and asked for existing loans to be extended by three years to 2017.

The senior secured floating rate loan tranche, which matures on Feb. 1, 2019, was lifted from an initial amount of $500 million due to investor demand, Germany's largest cable TV company said in a statement on Monday.

Goldman Sachs, BNP Paribas, Deutsche Bank , JP Morgan, Morgan Stanley and The Royal Bank of Scotland are arranging the extension request, it said.

Lenders are asked to submit their extension approvals by Feb. 1.

KDG, which had net debt of 2.85 billion euros ($3.7 billion) at the end of September, last year promised investors a net profit and a dividend payout for this year as it launched an 800 million euro debt refinancing to reduce its interest costs.

A few months later it trimmed its outlook for full-year sales after revenues from its phone business fell short of expectations.

KDG offers analogue and digital TV, broadband Internet and fixed-line phone services via cable and competes with Deutsche Telekom and Vodafone.