{"type_number":"717A","canonical_url":"https://tubeofile.com/tubes/717A","manufacturer":"Western Electric","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Octal","description":"High-frequency sharp-cutoff pentode in miniature metal-shell envelope (\"doorknob\"). Developed by Western Electric as a low-noise front-end amplifier for VHF/UHF radar receivers. Electrically identical to 713A but with micanol wafer base and metal shell instead of 7-pin octal bakelite.","is_directly_heated":false,"completeness":"medium","notes":["Known as the 'little doorknob' due to its miniature metal-shell envelope (34 mm diameter, 37 mm tall excluding pins).","Suppressor grid (g3) is internally connected to the metal shell (pin 1) which serves as a base shield.","Pins 3 and 5 are both cathode connections — both should be grounded for proper RF shielding.","The 713A and 717A are electrically identical; only the base construction differs.","Manufactured by Western Electric and Tung-Sol during WWII in large quantities for radar service.","Datasheet typical operating conditions use Va=120V and Vs=120V (equal plate and screen voltages).","Grid voltage for Ip = 10 µA (approx. cutoff): -9 V."],"references":["https://frank.pocnet.net/sheets/127/7/713A.pdf","https://tdsl.duncanamps.com/show.php?des=717A"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=717A","radiomuseum":"https://www.radiomuseum.org/tubes/tube_717a.html"},"raw_equivalents":["VT-269","CV3594"],"equivalents":[],"similar":[{"type_number":"384A","reason":"Earlier Western Electric pentode from which the 717A was derived; different base and ratings","has_detail_page":false},{"type_number":"6AK5","reason":"Similar sharp-cutoff RF pentode on B7G base with higher gm (5.1 mA/V) and different pinout — not a drop-in","has_detail_page":true},{"type_number":"713A","reason":"Electrically identical pentode but in 7-pin octal bakelite base — not pin-compatible due to different base","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Suppressor Grid (shell/base shield)","function_code":"g3","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Cathode","function_code":"k","notes":null},{"pin_number":"4","function":"Control Grid","function_code":"g1","notes":null},{"pin_number":"5","function":"Cathode","function_code":"k","notes":null},{"pin_number":"6","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Anode","function_code":"a","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"6.3","numeric_value":"6.3","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.175","numeric_value":"0.175","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"ss_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"180","numeric_value":"180","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"120","numeric_value":"120","unit":"V","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"10.1","numeric_value":"10.1","unit":"mA","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"120","numeric_value":"120","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"120","numeric_value":"120","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-2","numeric_value":"-2","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"7.5","numeric_value":"7.5","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"2.5","numeric_value":"2.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"250000","numeric_value":"250000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"4.0","numeric_value":"4","unit":"mA/V","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:30:51.695Z"}