{"type_number":"EL12","canonical_url":"https://tubeofile.com/tubes/EL12","manufacturer":"Telefunken","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Y8A","description":"Indirectly-heated output pentode for single-ended and push-pull audio amplification","is_directly_heated":false,"completeness":"high","notes":["Cathode-bias only — the datasheet explicitly prohibits fixed-bias operation.","Separate cathode resistors required per tube in push-pull configurations.","Va_max of 350V is the Telefunken/RFT rating; Philips/Valvo versions are conservatively rated to 250V. Variants with voltage suffix (/325, /375, /425) are factory-selected for higher voltages.","No pin-compatible equivalents; EL36/6CM5 is functionally similar but uses an Octal base."],"references":["https://frank.pocnet.net/sheets/082/e/EL12.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EL12","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el12.html"},"raw_equivalents":["EL12/325","EL12spez"],"equivalents":[{"type_number":"EL12spez","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"6CM5","reason":"Functionally similar (American EL36 equivalent) but Octal base vs Y8A — not pin-compatible","has_detail_page":false},{"type_number":"EL12/375","reason":"Factory-selected variant rated for 375V operation — same Y8A base and pinout, but verify transformer voltage matches this rating","has_detail_page":true},{"type_number":"EL12/425","reason":"Factory-selected variant rated for 425V operation — same Y8A base and pinout, highest voltage variant","has_detail_page":true},{"type_number":"EL150","reason":"Closely related Telefunken variant — same Y8A base, similar to EL12/350","has_detail_page":true},{"type_number":"EL35","reason":"Related power pentode in the same Brans family — different base, not pin-compatible","has_detail_page":true},{"type_number":"EL36","reason":"Functionally similar but Octal base vs Y8A — not pin-compatible","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Suppressor Grid (internally connected to cathode)","function_code":"g3","notes":null},{"pin_number":"2","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"3","function":"Control Grid","function_code":"g1","notes":null},{"pin_number":"4","function":"Cathode","function_code":"k","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":"Anode","function_code":"a","notes":null},{"pin_number":"8","function":"No Connection","function_code":"nc","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":"1.2","numeric_value":"1.2","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":"350","numeric_value":"350","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"350","numeric_value":"350","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"18","numeric_value":"18","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":"90","numeric_value":"90","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":"0.2","numeric_value":"0.2","unit":"MΩ","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"0.7","numeric_value":"0.7","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":"-7","numeric_value":"-7","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"72","numeric_value":"72","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"8","numeric_value":"8","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":"15","numeric_value":"15","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"90","numeric_value":"90","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"8","numeric_value":"8","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"3500","numeric_value":"3500","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"<0.7","numeric_value":null,"unit":"pF","param_group":"capacitances"},{"key":null,"display_name":"Screen Dissipation (max, driven)","value":"5","numeric_value":"5","unit":"W","param_group":null}]}],"synced_at":"2026-04-07T12:43:01.819Z"}