Robt Ptak (born October 13, 1970) is an American rock singer-songwriter, guitarist, bassist, and record producer who is the co-founding member and bassist/backing vocalist for 1990s pop punk band Size 14.

Ptak can also be heard singing backing vocals and the high falsettos parts on the band's songs.

In 1996 Ptak toured with Jakob Dylan as a bass player and backup vocalist, playing songs from the album titled "Bringing Down the Horse" during which he recorded "Pain in my Head", with Andrew Slater Dylan's manager, which was engineered by Tobi Miller of The Wallflowers.

Later Ptak moved to New York City to start a live version of his solo-project Artificial Joy which consisted of singer Milena Mepris (who later went to form Pin Me Down), bassist Mark Cevellos, and drummer Alex Elena.

Ptak was the manager of Pin Me Down[4][5] the side project from Bloc Party guitarist Russell Lissack and Artificial Joy singer Milena Mepris.