(1) Tested Very Strong RCA 6BK5 Tube with Box Date Code CL RCA 6BK5 Tube (c)

(1) Tested Strong RCA 6BY6 Tube with Box Date Code BK Heptode Tube

(1) Tested Very Strong RCA 5654 Tube (6AK5) Code BK Sharp Cutoff Pentode Tube

(1) Tested Strong RCA 12H6 Tube with Cleaver Brooks Box Date Code DE Diode (d)

(1) Tested Strong RCA 12H6 Tube with Cleaver Brooks Box Date Code DE Diode (c)

(1) Tested Strong RCA 6BK5 Tube with Box Date Code AY Beam Power Tube

(1) Tested Very Strong RCA 6GN8 Tube with Box Date Code DL High Mu Triode Tube

(1) Tested 1949 RCA JRC 3Q4 Tube with Box Date Code 6-48 Mil Spec RCA 3Q4 Tube