{"type_number":"EL11","canonical_url":"https://tubeofile.com/tubes/EL11","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Y8A","description":"Output pentode for audio amplifiers. Pre-war German steel tube with Y8A footless base, introduced in 1938. Electrically identical to the EL3N and EL3 but on a different base. Delivers 4.5 W in Class A single-ended and 8.2 W in Class AB push-pull.","is_directly_heated":false,"completeness":"high","notes":["Electrically identical to the EL3N (P8A side-contact base) and EL3 (P-base). For push-pull operating data, the Philips datasheet refers to the EL3 datasheet.","Screen dissipation has two limits: max 1.2 W at zero signal (idle) and max 2.5 W at maximum output power.","Heater-to-cathode voltage max 50 V (DC or RMS AC), with max cathode resistor of 5 kΩ.","Pin 3 connects cathode and suppressor grid internally.","Class AB push-pull (2x EL11): Va = 250 V, Vg2 = 250 V, Rk = 140 Ω, Raa = 10 kΩ delivers 8.2 W at 3.1% distortion.","μg2g1 = 25 suggests approximate triode μ ≈ 25 when triode-strapped, but no manufacturer triode-connected data is published."],"references":["https://frank.pocnet.net/sheets/030/e/EL11.pdf","https://frank.pocnet.net/sheets/204/e/EL11_EL11N.pdf"],"source_urls":{"r_type":"https://www.r-type.org/exhib/aaa0943.htm","tdsl":"http://tdsl.duncanamps.com/show.php?des=EL11","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el11.html"},"raw_equivalents":["EL11N","AV1037","6E102"],"equivalents":[],"similar":[{"type_number":"EL3","reason":"Electrically identical but older P-base — not Octal","has_detail_page":true},{"type_number":"EL3N","reason":"Electrically identical but P8A side-contact base — not Octal","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"2","function":"Control Grid","function_code":"g1","notes":null},{"pin_number":"3","function":"Cathode + Suppressor Grid (internally connected)","function_code":"k","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Heater","function_code":"h","notes":null},{"pin_number":"6","function":"Heater","function_code":"h","notes":null},{"pin_number":"7","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"8","function":"Anode","function_code":"a","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":"Pentode","tube_type_key":"power_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"275","numeric_value":"275","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"9","numeric_value":"9","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":"55","numeric_value":"55","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"50","numeric_value":"50","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":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-6","numeric_value":"-6","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"36","numeric_value":"36","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"4","numeric_value":"4","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"50000","numeric_value":"50000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"9","numeric_value":"9","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"150","numeric_value":"150","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"4.5","numeric_value":"4.5","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"7000","numeric_value":"7000","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.8","numeric_value":"0.8","unit":"pF","param_group":"capacitances"},{"key":null,"display_name":"μg2g1","value":"25","numeric_value":"25","unit":"—","param_group":null}]}],"synced_at":"2026-04-07T12:42:40.097Z"}