The British stars contributed to the latest Band Aid track, which became the fastest selling single of 2014 after just two days of going on sale to help raise funds for victims of Ebola.
Geldof was bowled over by the singers' efforts and admits he was so "staggered" by their voices that he wants to release their individual efforts as solo tracks.
The Boomtown Rats star also praised the "rage and passion" of Sinead O'Connor's performance on the new single.
He tells Britain's Capital Fm radio, "You're just there going, 'How do you sing like that? How is it possible?' There has to be individual versions of this. I was staggered by the voices. With Sam's version, Ed's version, you're just going to go, 'Wow'. They do it so different to what's in my head."
The new release, which also features stars including Bono, Chris Martin, Ellie Goulding, Emeli Sande and Paloma Faith, follows previous revivals in 1989 and 2004.