(1) Tested Philco Type 41 Tube Date Code 7U Engraved Base Power Pentode Tube

(1) Tested Arcturus Type 41 Tube Date Code E5 Arcturus Power Pentode 41 Tube

(1) Tested Philco Type 41 Tube Date Code 6S Engraved Base Power Pentode 41 Tube

(1) Tested Strong Philco 6HB6 Tube with Box Date Code EXT Power Pentode Tube (a)

(1) Tested RCA Type 41 Tube Date Code H6E Meatball Logo Power Pentode 41 Tube

(1) Tested RCA JRC 6AK6 Tube Date Code 3-09 RCA 6AK6 Power Amplifier Pentode

(1) Tested RCA Cunningham Type 41 Tube Engraved Base Date Code J12 Power Pentode

(1) Tested RCA Victor Type 38 Tube Date Code 613 RCA 38 Tube Power Pentode Tube