Sarangi maestro and classical singer Ustad Sultan Khan, the soulful voice behind hits like 'Piya Basanti Re' and 'Albela Sajan Aayo Re', passed away on Sunday afternoon in New Delhi after prolonged illness. The Padma Bhushan awardee, 71-year-old Khan, who hailed from a family of Sarangi players in Jodhpur, was on dialysis for some time, family sources said.