{"type_number":"EL54","canonical_url":"https://tubeofile.com/tubes/EL54","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"P8A","description":"Rare AF output pentode rated for higher-voltage operation (up to 425 V anode and screen); indirectly heated. Philips/Mullard side-contact (P8A) version of the EL6 power pentode, selected for elevated voltage ratings. Top-cap anode connection. Introduced late 1940s.","is_directly_heated":false,"completeness":"high","notes":["Very rare late-1940s Philips output pentode — the EL54 is the voltage-selected, side-contact (P8A) counterpart to the EL6 (which uses the B8A side-contact Octal base). Electrically identical structure to the EL6 but rated for 425 V on both anode and screen.","Anode connection is via top cap. The P8A side-contact base carries heater, cathode, grids, and metallization — not compatible with standard Octal (IO) or B8A sockets.","Maximum ratings match the EL6 (Pa=18 W, Ik=90 mA, Ps=2 W) except for the raised Va_max and Vs_max (425 V vs 250 V / 275 V) — intended for higher-B+ push-pull output stages.","TDSL and Radiomuseum provide only maximum ratings; detailed operating-point data (gm, ra, Ia, Pout) is not published in commonly available references. Designers should use EL6 operating-point data as a starting point at Va ≤ 250 V.","Rare enough that substitution is rarely an issue in practice — when found in equipment it is typically replaced with an EL6 if the circuit voltage permits."],"references":["https://tdsl.duncanamps.com/show.php?des=EL54","https://www.radiomuseum.org/tubes/tube_el54.html"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EL54","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el54.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"4699","reason":"Related EL6-family type listed by Radiomuseum with slightly different ratings","has_detail_page":false},{"type_number":"EL12N","reason":"Different base and slightly different data per Radiomuseum — not pin-compatible","has_detail_page":true},{"type_number":"EL53","reason":"Same P8A base and voltage rating (425 V) but lower Pa_max (9 W vs 18 W) — smaller output pentode of the same family","has_detail_page":true},{"type_number":"EL6","reason":"Same electrical structure and characteristics but on B8A side-contact base (not P8A) and rated only to 250 V anode — EL54 is essentially an EL6 on the P8A base selected for 425 V operation","has_detail_page":true},{"type_number":"EL6/425","reason":"Voltage-selected EL6 variant normally replaceable with EL54 per Radiomuseum; differs slightly in detailed ratings","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Control Grid","function_code":"g1","notes":null},{"pin_number":"2","function":"Cathode","function_code":"k","notes":null},{"pin_number":"3","function":"Heater","function_code":"h","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"6","function":"Metallization (external shield)","function_code":"ia","notes":null},{"pin_number":"7","function":"Suppressor Grid (internally connected to cathode)","function_code":"g3","notes":null},{"pin_number":"8","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"TC","function":"Anode (top cap)","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":"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":"425","numeric_value":"425","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"425","numeric_value":"425","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","numeric_value":"2","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":"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":"20000","numeric_value":"20000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"14.5","numeric_value":"14.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"8.2","numeric_value":"8.2","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":"0.7","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-09T05:18:22.391Z"}