Final answer:
The new instruments used on the Rubber Soul and Revolver albums were the sitar and tambura.
Step-by-step explanation:
The new instruments used on the Rubber Soul and Revolver albums by The Beatles were the sitar and tambura. The sitar is a stringed instrument with a distinctive sound that is typical of Indian classical music. George Harrison, a member of The Beatles, introduced the sitar to their music, notably in the song 'Norwegian Wood (This Bird Has Flown).' The tambura is a drone instrument that provides a constant harmonic background.