 Soon after , inspired by the Beatles ' film A Hard Day 's Night , the band decided to equip themselves with similar instruments to the Fab Four : a Rickenbacker twelve @-@ string guitar for McGuinn , a Ludwig drum kit for Clarke , and a Gretsch Tennessean guitar for Clark ( although Crosby commandeered it soon after , resulting in Clark switching to tambourine ) . In October 1964 , Dickson recruited mandolin player Chris Hillman as the Jet Set 's bassist . Hillman 's background was more oriented towards country music than folk or rock , having been a member of the bluegrass groups the Scottsville Squirrel Barkers , the <unk> ( also known as the Golden State Boys ) , and , concurrently with his recruitment into the Jet Set , the Green Grass Group . 
