{"type_number":"7AD7","canonical_url":"https://tubeofile.com/tubes/7AD7","manufacturer":"Tung-Sol","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Loctal","description":"Sharp-cutoff power pentode in loctal (lock-in) construction, characterized by high transconductance (9500 umhos). Designed for wide-band intermediate frequency and video amplifier service in television receivers. Manufactured by Tung-Sol, introduced 1948.","is_directly_heated":false,"completeness":"medium","notes":["Tung-Sol datasheet marked as 'Tentative Data' (1948).","Two typical operating conditions given: Class A1 amplifier (Va=300V, Vg2=150V) and Class A1 television amplifier (Va=300V, Vg2=125V).","Maximum grid #4 circuit resistance: 0.25 Mohm (fixed bias), 1 Mohm (self-bias).","GE Essential Characteristics lists max plate dissipation as 10W, screen voltage max 150V.","Grid #3 voltage connected to pin #7 at socket (cathode connection)."],"references":["https://frank.pocnet.net/sheets/127/7/7AD7.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=7AD7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_7ad7.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"6CH6","reason":"Brans lists in same group — similar sharp-cutoff pentode but different base (Noval vs Loctal)","has_detail_page":true},{"type_number":"6CL6","reason":"Brans lists in same group — similar characteristics but Noval base","has_detail_page":true},{"type_number":"6GK6","reason":"Brans lists in same group — similar power pentode but Noval base, different era","has_detail_page":true},{"type_number":"EL803","reason":"Brans lists in same group — European equivalent type but different base","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Heater","function_code":"h","notes":null},{"pin_number":"2","function":"Plate","function_code":"a","notes":null},{"pin_number":"3","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"4","function":"Grid #3 (connected to pin #7 at socket)","function_code":"g3","notes":null},{"pin_number":"5","function":"Grid #5 (connected to pin #7 at socket)","function_code":"g3","notes":null},{"pin_number":"6","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"7","function":"Cathode","function_code":"k","notes":null},{"pin_number":"8","function":"Heater","function_code":"h","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":"0.6","numeric_value":"0.6","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Power Pentode","tube_type_key":"power_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"10","numeric_value":"10","unit":"W","param_group":"absolute_max"},{"key":"Vg2_max","display_name":"Screen Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pg2_max","display_name":"Screen Dissipation (max)","value":"1.2","numeric_value":"1.2","unit":"W","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"90","numeric_value":"90","unit":"V","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"300","numeric_value":"300","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-3","numeric_value":"-3","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"28","numeric_value":"28","unit":"mA","param_group":"typical_operating"},{"key":"Vg2","display_name":"Screen Voltage","value":"150","numeric_value":"150","unit":"V","param_group":"typical_operating"},{"key":"mAg2","display_name":"Screen Current","value":"7","numeric_value":"7","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"300000","numeric_value":"300000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"9.5","numeric_value":"9.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.03","numeric_value":"0.03","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"11.5","numeric_value":"11.5","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"7.5","numeric_value":"7.5","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:31:50.258Z"}