{"type_number":"6L6","canonical_url":"https://tubeofile.com/tubes/6L6","manufacturer":"RCA","tube_type_key":"beam_tetrode","tube_type_display_name":"Beam Tetrode","base_name":"Octal","description":"Beam power tube introduced by RCA in 1936, the first commercially successful beam tetrode. Widely used in audio power amplifiers, guitar amplifiers, and industrial equipment. The 6L6 family includes later variants (6L6G, 6L6GA, 6L6GB, 6L6GC) with progressively higher ratings.","is_directly_heated":false,"completeness":"high","notes":["The original 6L6 (metal envelope) has lower ratings than later variants: Pa_max = 19 W vs 23 W (6L6GA/GB) or 30 W (6L6GC). Screen voltage max is 270 V vs 450 V (6L6GC). Data here is for the original 6L6.","Pin 1 connects to the metal shell on the original metal-envelope 6L6. On glass-envelope variants (6L6G, 6L6GT), pin 1 is not connected. Pin 6 has no internal connection on any variant.","5881 is a ruggedised military version with identical ratings to the original 6L6. KT66 is a GEC equivalent with slightly different construction but very similar characteristics.","Rg_max of 0.1 MΩ applies to fixed-bias operation. In self-bias (cathode resistor) circuits, higher grid resistor values up to 0.5 MΩ are often used in practice, though the RCA datasheet specifies 0.1 MΩ.","Triode-strapped data sourced from Tom Schlangen's 'Pentodes Strapped as Triodes' (2009) and corroborated by TDSL push-pull triode operating data.","CV1948 is the British military designation equivalent (Brans Vademecum 1963)."],"references":["https://w140.com/tekwiki/images/a/a8/RCA_6L6_data_sheet.pdf","https://frank.pocnet.net/sheets/049/6/6L6.pdf"],"source_urls":{"r_type":"http://r-type.org/exhib/aaa0101.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=6L6","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6l6.html"},"raw_equivalents":["6L6G","6L6GT","5881","CV1286","VT-115","6L6GC","6L6GA","6L6GB","6L6WGB","6P3S","6P3S-E","6N3C","6L6A","CV1948","5932","12AB5","6P3P"],"equivalents":[{"type_number":"5881","equivalence_type":"direct","notes":null},{"type_number":"6L6GC","equivalence_type":"direct","notes":null},{"type_number":"6N3C","equivalence_type":"direct","notes":null},{"type_number":"6P3P","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"5743","reason":"Sams lists as substitute — ruggedized military variant, verify ratings before substituting","has_detail_page":true},{"type_number":"7581","reason":"Brans cross-lists with 6L6 family — improved beam tetrode with higher ratings (Pa_max 35W vs 19W for original 6L6)","has_detail_page":true},{"type_number":"EL37","reason":"Sams lists as substitute — Mullard Octal power pentode with similar characteristics but different internal design","has_detail_page":true},{"type_number":"KT66","reason":"GEC equivalent with similar characteristics but different internal construction — verify bias compatibility before substituting","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Metal Shell (internal shield on metal envelope)","function_code":"ia","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","function_code":"g2","notes":null},{"pin_number":"5","function":"Control Grid","function_code":"g1","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}],"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":"0.9","numeric_value":"0.9","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Beam Tetrode","tube_type_key":"beam_tetrode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"360","numeric_value":"360","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"270","numeric_value":"270","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"19","numeric_value":"19","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"2.5","numeric_value":"2.5","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"125","numeric_value":"125","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"200","numeric_value":"200","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"0.1","numeric_value":"0.1","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"350","numeric_value":"350","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-18","numeric_value":"-18","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"54","numeric_value":"54","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":"33000","numeric_value":"33000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"5.2","numeric_value":"5.2","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"300","numeric_value":"300","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"11","numeric_value":"11","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"4200","numeric_value":"4200","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.6","numeric_value":"0.6","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"10","numeric_value":"10","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"12","numeric_value":"12","unit":"pF","param_group":"capacitances"}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"power_triode","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":"15","numeric_value":"15","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"125","numeric_value":"125","unit":"mA","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"300","numeric_value":"300","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"42","numeric_value":"42","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1700","numeric_value":"1700","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"4.7","numeric_value":"4.7","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"8","numeric_value":"8","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T19:04:34.864Z"}