TOKYO, June 20 (Reuters) - A group led by private equity firm Bain Capital will launch a $445 million bid for Japan's D&M Holdings Inc, the maker of Denon audio equipment, from U.S. buyout firm Ripplewood.

RHJ International SA, which took over Japanese assets from Ripplewood, auctioned off its roughly 49 percent stake in D&M, an audio equipment firm that also owns the Marantz brand.

Bain Capital tied up with Japanese audio maker Kenwood Corp to buy D&M, and had been competing against Japanese private equity fund Advantage Partners, according to sources familiar with the transaction.

U.S. electronics retailer Best Buy Co and Merrill Lynch Global Private Equity, the private equity investment arm of Merrill Lynch, which had also been eyeing D&M, withdrew after the first round of bidding, said the sources.

Bain Capital will bid 510 yen per share for D&M Holdings, an 8.5 percent premium over Thursday's closing price and valuing the audio maker at 48 billion yen, D&M said in a statement on Friday.

D&M is owned 12 percent by Dutch electronics maker Philips Electronics

Bain Capital will launch the bid by July 25 and aim to acquire 100 percent of D&M, the audio maker said.

Bain Capital has secured about 70 billion yen in loans, which will be arranged by banks including Morgan Stanley, which advised D&M. The lenders also include Societe Generale, Aozora Bank Ltd, Mizuho Corporate Bank and Shinsei Bank Ltd, the sources said, asking not to be identified because the deal has not been closed.

Goldman Sachs Group Inc and Lehman Brothers Holdings Inc advised Bain Capital, D&M said.

RHJ International, which also holds stakes in Asahi Tec Corp and Columbia Music Entertainment Inc, said it gained 15.8 billion yen from the sale of D&M.

Of the total lending, about 50 billion yen will be used for the purchase of D&M and the remainder will be spent on future acquisitions, they said.

Philips, the second-biggest shareholder, is expected to sell its stake once the highest bidder launches a full buyout offer.