{"type_number":"EL39","canonical_url":"https://tubeofile.com/tubes/EL39","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Octal","description":"High-power output pentode designed for Class AB push-pull stages, with top cap anode connection. Predecessor to the EL34.","is_directly_heated":false,"completeness":"high","notes":["Anode is connected via top cap — not available on the octal base pins.","Pin 3 is unused (no connection). Suppressor grid (g3) is on pin 6, which differs from the EL38 where g3 is on pin 1.","4654K is the octal-based variant and is pin-compatible with the EL39.","EL50 and 4654 (P8A base) are sometimes listed as equivalents but have different ratings — they are not direct substitutes.","For push-pull stages, it is inadvisable to employ high anode voltages unless the grid bias is fixed.","The 4654 datasheet specifies a maximum anode voltage of 600V; the EL50 datasheet shows operation at 800V. Use 600V as the safe maximum unless the specific tube variant is confirmed as EL50-rated."],"references":["https://frank.pocnet.net/sheets/101/4/4654.pdf","https://frank.pocnet.net/sheets/101/e/EL50.pdf","https://frank.pocnet.net/sheets/030/e/EL50.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EL39","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el39.html"},"raw_equivalents":["4654K"],"equivalents":[],"similar":[{"type_number":"4654","reason":"B8A base version — same electrical characteristics but different base, not pin-compatible with Octal EL39","has_detail_page":false},{"type_number":"EL50","reason":"Similar ratings but B8A side-contact base vs Octal — not pin-compatible","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":"No Connection","function_code":"nc","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":"Suppressor Grid","function_code":"g3","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Cathode","function_code":"k","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":"1.35","numeric_value":"1.35","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":"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":"Va","display_name":"Anode Voltage (typical)","value":"400","numeric_value":"400","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"425","numeric_value":"425","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-33","numeric_value":"-33","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"45","numeric_value":"45","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"5","numeric_value":"5","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","numeric_value":"6","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"52.5","numeric_value":"52.5","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"5000","numeric_value":"5000","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"}]}],"synced_at":"2026-04-07T12:44:47.195Z"}