{"type_number":"7C7","canonical_url":"https://tubeofile.com/tubes/7C7","manufacturer":"Sylvania","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Loctal","description":"Sharp-cutoff pentode on Loctal base. Loctal equivalent of the 6SJ7. Designed for voltage amplifier, detector, and AF preamplifier service in radio receivers using the Loctal tube complement.","is_directly_heated":false,"completeness":"high","notes":["Loctal (lock-in) base — 8-pin base with metal locking ring. Not compatible with Octal or Noval sockets.","GE Essential Characteristics: Pa_max 1.0 W, Va_max 300 V, Vs_max 100 V, Va(typ) 250V, Vs(typ) 100V, Vg=-3V, Ia=2.0mA, Is=0.5mA, gm=1300, Rp=2000000.","Valve Equivalents reference lists this as a pentode on B8G (Loctal) base with 6.3V heater.","Brans Vademecum lists many equivalent types including 6SJ7, EF86, EF37A, and numerous others.","Raytheon data shows an alternate higher-current operating condition (Va=250V, Vg=-15V, Ia=75mA, gm=3750, Rp=60000) which appears to be a different tube with the same type number — the GE data at 2mA/1300 umhos matches the small-signal pentode application."],"references":["https://frank.pocnet.net/sheets/127/7/7C7.pdf","https://tdsl.duncanamps.com/show.php?des=7C7"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=7C7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_7c7.html"},"raw_equivalents":["VT-193"],"equivalents":[],"similar":[{"type_number":"5879","reason":"Similar sharp-cutoff AF pentode but Noval base — not pin-compatible","has_detail_page":true},{"type_number":"6SJ7","reason":"Electrically identical but Octal base — not compatible with Loctal sockets","has_detail_page":true},{"type_number":"6SJ7GT","reason":"Same tube as 6SJ7 in GT glass envelope — same electricals, Octal base","has_detail_page":false},{"type_number":"EF86","reason":"Similar low-noise AF pentode but Noval base — different pin count and layout","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Shell","function_code":"nc","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Anode","function_code":"a","notes":null},{"pin_number":"4","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"5","function":"Suppressor Grid (g3)","function_code":"g3","notes":null},{"pin_number":"6","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Cathode","function_code":"k","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":"0.15","numeric_value":"0.15","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":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"100","numeric_value":"100","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"1.0","numeric_value":"1","unit":"W","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode 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":"Vs","display_name":"Screen Voltage (typical)","value":"100","numeric_value":"100","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":"2.0","numeric_value":"2","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"0.5","numeric_value":"0.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"2000000","numeric_value":"2000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.3","numeric_value":"1.3","unit":"mA/V","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:32:28.652Z"}