Jussi Sydänmaa (born 26 June 1972) is a Finnish guitarist and a former founding member of the rock band Lordi, performing by the stage name of Amen until his departure in May 2022.

The municipality of Mäntsälä granted Sydänmaa with a statue named "Hard Rock Stone" on 26 June 2006.

He has also recorded guitar riffs which were used by Ari Pulkkinen to create the soundtrack for the video game Shadowgrounds.

Sydänmaa picked the guitar back up ten years later, when he began taking an interest in hard rock music.

After graduation, Sydänmaa did not go on to work in that field, as he had joined Lordi in the late 1990s under the stage name "Amen", and they had made their breakthrough in 2002.