Founding music director and conductor of the Singapore Symphony Orchestra (SSO) Choo Hoey left the country 20 years ago after stepping down - but he has not been forgotten by his friends and fans here.

And the 85-year-old maestro still has music in him, as he showed on Friday night when he returned for the Maestros Extravaganza, a two-night concert by the Singapore Chinese Orchestra (SCO), which invited him as one of three conductors in a performance to mark its 20th year.

When it was his turn to step onto the podium, he was greeted with loud applause at the Singapore Conference Hall.

After the two-hour concert that consisted mainly of Chinese and local compositions, a long queue of his admirers and friends waited to shake his hand, get his autograph or take a picture with him."It is good to be back and I cherish the opportunity to see them again," he said.

It was the third time Mr Choo has been back to conduct for the SCO since 2007. Two years ago, he was invited by the SSO to its 35th anniversary concert, and he returned again for the Singapore Golden Jubilee concert last August when he led Beethoven's Fifth Symphony.

He was a member of the first SCO board and was its adviser when it was inaugurated in 1996 - the same year he left the SSO, after leading the national symphony orchestra for 18 years, to return to Greece where he now lives with his Greek wife, Alexandra, 69, a retired archaeologist.

They have two sons, Choo Yen, 45, a molecular biologist, and Choo Lin, 42, a maritime lawyer. Both now live and work in England.

Elder brother Yen, who was in Singapore to catch his father conduct the SCO, will be among the recipients of an innovation award from the Queen at Buckingham Palace on July 14. He is being honoured for turning stem cells into replacement human cells to treat 70 diseases including cancer and diabetes.

The senior Mr Choo was born in Palembang, Sumatra, to schoolteacher parents. He came here to study at the former Chinese High School before leaving to take up his music education in London in 1951.

He is still busy conducting, mainly in Europe and China.

"I do only one or two concerts a month now because of my age," he explained.

In 2007, he went to China to help set up the Qingdao Symphony Orchestra and spent three years working in Shandong's capital city.

Just before coming to Singapore last week, he conducted the Tianjin Symphony Orchestra which played Rimsky-Korsakov's Golden Cockerel and Brahms' Second Symphony and Violin Concerto to rave reviews.

Although he has not been close to Singapore's classical music scene over the past two decades, he cautioned orchestras and the authorities here to pay greater attention to recruiting more good musicians, their programming and the quality of acoustics in the concert halls.

"It is not about how beautiful the concert halls are externally, but the sounds they can produce in them."

Referring to the renovated Victoria Concert Hall and the Esplanade Concert Hall, where he conducted the SSO recently, he said: "They used too much Japanese sound technology there and it may be too late to change now."

As for musicians, he felt strongly that Singapore orchestras should get only the best, no matter where they are from.

An orchestra must also build on a good and solid repertoire, he said.

When he was invited from Greece - where he has been working and living since the early 1970s - to start the SSO some 37 years ago, he said he insisted that at least one modern work by a 20th century composer be included in every concert.

"That's to keep the musicians in tune with the latest development in music and improve their playing skills," he explained.

He believed that changes in music trends and innovation often come from these works. For example, he pointed out, Stravinsky even asked manufacturers of instruments to tweak an instrument to accommodate a new sound he had created for a new piece of work.

Mr Choo said he keeps fit by walking and swimming in the sea near his home, which is about 300km from Athens.

"I keep up by reading on the latest developments and research and take on any assignment which comes, especially from Singapore," he added. "Music is all I know and do in my life."