(1) Tested RCA 6J6 Tube Medium Mu Twin Triode Tube (a)

(1) Tested RCA 6CX8 Tube with Box Date Code CR Medium Mu Triode Pentode Tube

(1) Tested RCA 6BQ7A Tube Date Code MZ RCA 6BQ7 A Medium Mu Twin Triode Tube

(1) Tested RCA 6J6 Tube with Box RCA Medium Mu Twin Triode Tube (b)

(1) Tested RCA 7057 TUbe Date Code 65-39 Medium Mu Twin Triode Tube

(1) Tested RCA 6CX8 Tube with Box Date Code DM Medium Mu Triode Pentode Tube

(1) Tested RCA 6BJ8 Tube Date Code AC RCA Twin Diode Triode Tube

(1) Tested RCA 6AZ8 Tube with Box Date Code KG Medium Mu Triode Cutoff Pentode