(1) Tested Philco Type 24A Tube Date Code 56 Type 24 A Tube Sharp Cutoff Tetrode

(1) Tested Panama Type 24A Tube Date Code HK3 Engraved Base Type 24 A Tube

(1) Tested Cunningham Type 24A Tube Date Code X3 24 A Tube Sharp Cutoff Tetrode

(1) Tested RCA Type 24A Tube Date Code T4 RCA 24 A Tube Sharp Cutoff Tetrode

(1) Tested Tung-Sol Type 24 Tube Engraved Base Tung Sol 24 Tetrode Tube (c)

(1) Tested RCA Type 24A Tube Date Code H2 M-R RCA 24 A Tube Sharp Cutoff Tetrode

(1) Tested Silvertone 224A Tube Date Code 3AX Type 24 Tube Engraved Base Tetrode

(1) Tested Tung-Sol Type 24 Tube Engraved Base Date Code 7-3 Tetrode Tube