{"type_number":"6J7","canonical_url":"https://tubeofile.com/tubes/6J7","manufacturer":"RCA","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Octal","description":"Sharp-cutoff pentode for use as RF amplifier, IF amplifier, detector, or audio voltage amplifier. Metal-envelope octal tube with top-cap control grid, introduced 1935. Predecessor to the 6SJ7, which moved the control grid connection to the base. Electrically equivalent to the 6C6 except for base type.","is_directly_heated":false,"completeness":"high","notes":["Pin 1 is the metal shell and internal shield connection, which should be connected to cathode for proper electrostatic shielding. On glass variants (6J7G, 6J7GT), pin 1 serves the same function.","The control grid (g1) is brought out to a top cap, not to a base pin. This was standard practice for RF pentodes in the mid-1930s to minimize grid-to-anode capacitance. The successor 6SJ7 eliminated the top cap by using improved internal shielding.","The grid circuit DC resistance should not exceed 1.0 megohm under rated maximum conditions.","The 6J7 was the international standard input-stage amplifier tube for nearly two decades, widely used in radio receivers, test equipment, and early audio amplifiers."],"references":["https://frank.pocnet.net/sheets/093/6/6J7.pdf"],"source_urls":{"r_type":"https://www.r-type.org/exhib/aaa0625.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=6J7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6j7.html"},"raw_equivalents":["6J7G","6J7GT","VT-91","VT-91A","CV1074","CV1935","CV1936","CV1937","ARP16","1620","1223","6C6"],"equivalents":[{"type_number":"6C6","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"12J7GT","reason":"12.6V heater version (0.15A) — not a drop-in due to different heater voltage","has_detail_page":true},{"type_number":"6SJ7","reason":"Successor with identical electricals but control grid moved from top cap to pin 4 — different pin topology","has_detail_page":true},{"type_number":"EF36","reason":"Mullard equivalent but different pin assignments on the octal base (Mullard B8A-style wiring)","has_detail_page":true},{"type_number":"EF37","reason":"European Rimlock equivalent — different base (B8A vs Octal), similar electrical characteristics","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Shell and Internal Shield","function_code":"ia","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Plate (Anode)","function_code":"a","notes":null},{"pin_number":"4","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"5","function":"Suppressor Grid","function_code":"g3","notes":null},{"pin_number":"6","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Cathode","function_code":"k","notes":null},{"pin_number":"TC","function":"Control Grid","function_code":"g1","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":"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":"125","numeric_value":"125","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"0.75","numeric_value":"0.75","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"0.1","numeric_value":"0.1","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":"Rg_max","display_name":"Max Grid Resistor","value":"1","numeric_value":"1","unit":"MΩ","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":"1000000","numeric_value":"1000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.225","numeric_value":"1.225","unit":"mA/V","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.005","numeric_value":"0.005","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"7","numeric_value":"7","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"12","numeric_value":"12","unit":"pF","param_group":"capacitances"},{"key":null,"display_name":"Grid Voltage (cutoff)","value":"-7","numeric_value":"-7","unit":"V","param_group":null}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"1.75","numeric_value":"1.75","unit":"W","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":"-8","numeric_value":"-8","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"6.5","numeric_value":"6.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"10500","numeric_value":"10500","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.9","numeric_value":"1.9","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"20","numeric_value":"20","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"2.0","numeric_value":"2","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"5","numeric_value":"5","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"14","numeric_value":"14","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T19:04:26.767Z"}