{"type_number":"7Q7","canonical_url":"https://tubeofile.com/tubes/7Q7","manufacturer":"Sylvania","tube_type_key":"hexode","tube_type_display_name":"Hexode","base_name":"Loctal","description":"Pentagrid converter (heptode) in loctal (lock-in) construction, designed for use as a combined oscillator and mixer in superheterodyne receivers. Loctal equivalent of the 6SA7/6BE6 family. Introduced 1939, widely used in radio receivers through the 1950s.","is_directly_heated":false,"completeness":"high","notes":["GE Essential Characteristics: converter service at Va=250V, Vg2=100V, Vg1=-2V gives Ia=3.5mA, Ig2=8.5mA, gm=550 umhos (conversion), rp=1 Mohm.","Max plate dissipation 1.0W, max plate voltage 300V, max screen voltage 100V.","Raytheon lists substitute types 7I7, 7A8, 7B8.","Brans cross-references with 6BE6, 12BE6, and CV899."],"references":["https://tdsl.duncanamps.com/show.php?des=7Q7","https://www.radiomuseum.org/tubes/?tube=7Q7"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=7Q7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_7q7.html"},"raw_equivalents":["CV899"],"equivalents":[],"similar":[{"type_number":"14Q7","reason":"Same Loctal pinout but 12.6V heater — not interchangeable without heater rewiring","has_detail_page":false},{"type_number":"6BE6","reason":"Successor pentagrid converter in miniature B7G base — electrically similar but different socket","has_detail_page":true},{"type_number":"6SA7","reason":"Electrically similar pentagrid converter but Octal base — not pin-compatible with Loctal","has_detail_page":true},{"type_number":"7B8","reason":"Predecessor pentagrid converter in Loctal — different characteristics","has_detail_page":false}],"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":"Grids 2 & 4 (Screen)","function_code":"g2","notes":null},{"pin_number":"4","function":"Grid 5 (Suppressor)","function_code":"g3","notes":null},{"pin_number":"5","function":"Grid 3 (Signal Grid)","function_code":"g3_sig","notes":null},{"pin_number":"6","function":"Grid 1 (Oscillator Grid)","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":"0.3","numeric_value":"0.3","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentagrid Converter","tube_type_key":"hexode","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":"1","numeric_value":"1","unit":"W","param_group":"absolute_max"},{"key":"Vg2_max","display_name":"Screen Voltage (max)","value":"100","numeric_value":"100","unit":"V","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"250","numeric_value":"250","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":"Vg2","display_name":"Screen Voltage","value":"100","numeric_value":"100","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"3.5","numeric_value":"3.5","unit":"mA","param_group":"typical_operating"},{"key":"mAg2","display_name":"Screen Current","value":"8.5","numeric_value":"8.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1000000","numeric_value":"1000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"0.55","numeric_value":"0.55","unit":"mA/V","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:32:46.381Z"}