{"type_number":"EL55","canonical_url":"https://tubeofile.com/tubes/EL55","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Magnoval","description":"AF output power pentode on Magnoval base; indirectly heated. Developed by Philips for professional audio and broadcast applications. Capable of 30 W anode dissipation with relatively high transconductance for its power class.","is_directly_heated":false,"completeness":"high","notes":["Magnoval (B9D) base — a 9-pin base larger than Noval, designed for higher-power tubes requiring better heat dissipation and higher voltage insulation.","Used in Philips professional broadcast equipment and studio audio amplifiers.","No widely available pin-for-pin equivalents exist — the EL55 is specific to the Philips Magnoval professional range.","Not found in TDSL database. Limited online datasheet availability; specifications sourced from Philips professional tube literature."],"references":["https://tdsl.duncanamps.com/show.php?des=EL55","https://www.radiomuseum.org/tubes/?tube=EL55"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EL55","radiomuseum":null},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"EL156","reason":"Higher-power Magnoval pentode (40W Pa) from same Philips professional range — similar base but higher ratings","has_detail_page":true},{"type_number":"EL34","reason":"Similar power class pentode (25W Pa) but Octal base — different socket and pinout, not pin-compatible","has_detail_page":true},{"type_number":"EL50","reason":"Earlier Philips power pentode family (18W Pa) on P8A side-contact base — different socket, lower power","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Suppressor Grid (g3)","function_code":"g3","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 (g2)","function_code":"g2","notes":null},{"pin_number":"5","function":"Control Grid (g1)","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},{"pin_number":"9","function":"Internal Shield / Metallization","function_code":"ia","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":"1.3","numeric_value":"1.3","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":"600","numeric_value":"600","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":"30","numeric_value":"30","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"8","numeric_value":"8","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"150","numeric_value":"150","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"150","numeric_value":"150","unit":"V","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":"-12.5","numeric_value":"-12.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"100","numeric_value":"100","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"10","numeric_value":"10","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"15000","numeric_value":"15000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"11","numeric_value":"11","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"12","numeric_value":"12","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"2000","numeric_value":"2000","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T12:46:02.181Z"}