{"type_number":"4694","canonical_url":"https://tubeofile.com/tubes/4694","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"P8A","description":"Output pentode with P8A side-contact base; Philips factory designation for the EL3/375. Factory-selected EL3N rated for operation up to 375 V anode voltage. Designed for higher-voltage output stages where the standard EL3N's 250 V rating is insufficient.","is_directly_heated":false,"completeness":"medium","notes":["4694 and EL3/375 are identical — '4694' is the Philips factory number, 'EL3/375' is the Mullard-Philips designation.","Anode connection via top cap. P8A side-contact base carries heater, cathode, grids, and metallization.","Cathode-bias only — fixed bias is prohibited per the datasheet, same as all EL3 variants.","Factory-selected for operation at Va up to 375 V; standard EL3N is rated to 250 V."],"references":["https://tdsl.duncanamps.com/show.php?des=4694","https://www.radiomuseum.org/tubes/?tube=4694"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=4694","radiomuseum":"https://www.radiomuseum.org/tubes/tube_4694.html"},"raw_equivalents":["EL3/375"],"equivalents":[{"type_number":"EL3/375","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"EL3/425","reason":"Higher voltage-selected variant rated to 425 V","has_detail_page":false},{"type_number":"EL3N","reason":"Standard version rated to 250 V — electrically near-identical, but lower max voltage rating","has_detail_page":true},{"type_number":"EL53","reason":"Related Philips type — similar but different characteristics","has_detail_page":true}],"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":"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":"375","numeric_value":"375","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":"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":"Pout","display_name":"Output Power","value":"4.5","numeric_value":"4.5","unit":"W","param_group":"output"}]}],"synced_at":"2026-04-07T12:10:23.708Z"}