{"type_number":"5881","canonical_url":"https://tubeofile.com/tubes/5881","manufacturer":"Tung-Sol","tube_type_key":"beam_tetrode","tube_type_display_name":"Beam Tetrode","base_name":"Octal","description":"Ruggedized beam power tube designed for audio-frequency power amplifier applications. Tung-Sol original design, military equivalent 6L6WGB. Same pinout as 6L6 family with identical electrical characteristics to the original 6L6 but improved mechanical construction for vibration resistance. Widely used in guitar amplifiers.","is_directly_heated":false,"completeness":"high","notes":["5881 is the Tung-Sol commercial designation for the military 6L6WGB (MIL-HDBK-213A). Electrically identical to the original 6L6 with ruggedized construction for vibration resistance.","Maximum ratings are the same as the original 6L6: Va_max=400V, Vs_max=400V, Pa_max=23W, Ps_max=3W. These are lower than the 6L6GC (500V/450V/30W/5W).","Triode-strapped data from RCA datasheet: at Va=250V, Vg1=-18V, Ia=52mA, gm=5250 µmhos, mu=8, ra=4000 Ω, Pout=1.4W into 4000 Ω. At Va=300V: Ia=52mA (zero-sig), 78mA (max-sig), Pout=1.8W.","Rg_max: 0.1 MΩ (fixed bias), 0.5 MΩ (cathode bias) — applies to both pentode and triode connections.","Pin 1 is No Connection on the 5881 (glass envelope). On the original metal-envelope 6L6, pin 1 connects to the metal shell. Pin 6 has no internal connection.","Triode-strapped Pa_max is 26W (higher than pentode Pa_max of 23W) per the RCA datasheet."],"references":["https://frank.pocnet.net/sheets/049/5/5881.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=5881","radiomuseum":"https://www.radiomuseum.org/tubes/tube_5881.html"},"raw_equivalents":["6L6WGB","6L6","6L6G","6L6GT","6L6GA","6L6GB","CV1286","VT-115","6P3S","6P3S-E","6N3C","6P3P"],"equivalents":[{"type_number":"6L6","equivalence_type":"direct","notes":null},{"type_number":"6N3C","equivalence_type":"direct","notes":null},{"type_number":"6P3P","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"6L6GC","reason":"Later 6L6 family variant with significantly higher ratings (Pa_max 30W vs 23W, Vs_max 450V vs 400V) — not a drop-in substitute in circuits designed for 6L6GC ratings","has_detail_page":true},{"type_number":"7581","reason":"Tung-Sol improved 6L6 type with higher ratings (Pa_max 30W) — same pinout but not a direct substitute in the other direction","has_detail_page":true},{"type_number":"EL37","reason":"Sams lists as substitute — Mullard Octal power pentode with similar application","has_detail_page":true},{"type_number":"KT66","reason":"Sams lists as substitute — GEC beam tetrode with similar characteristics but different internal construction","has_detail_page":true}],"pins":[{"pin_number":"1","function":"No Connection","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","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":"400","numeric_value":"400","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"400","numeric_value":"400","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"23","numeric_value":"23","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"3","numeric_value":"3","unit":"W","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":"250","numeric_value":"250","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":"-14","numeric_value":"-14","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"75","numeric_value":"75","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"4.3","numeric_value":"4.3","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"30000","numeric_value":"30000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"6.1","numeric_value":"6.1","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"6.7","numeric_value":"6.7","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"2500","numeric_value":"2500","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":"400","numeric_value":"400","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"26","numeric_value":"26","unit":"W","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":"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":"52","numeric_value":"52","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"4000","numeric_value":"4000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"5.25","numeric_value":"5.25","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"8","numeric_value":"8","unit":"—","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"1.4","numeric_value":"1.4","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"4000","numeric_value":"4000","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T19:01:22.041Z"}