{"type_number":"AL5/375","canonical_url":"https://tubeofile.com/tubes/AL5%2F375","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"P8A","description":"Factory-selected AL5 output pentode rated for operation up to 375 V anode voltage. P8A side-contact base with top-cap anode. 4 V indirectly-heated cathode. The '/375' suffix indicates factory selection for higher voltage operation. Electrically identical to the AL5 apart from heater characteristics and voltage rating.","is_directly_heated":false,"completeness":"high","notes":["The '/375' suffix indicates factory selection for Va_max = 375 V operation.","Must be used with self-bias (automatic grid bias) only — fixed bias operation is prohibited.","At full automatic grid bias: Rk = 175 ohm.","Electrically identical to EL5 apart from heater characteristics. Refer to AL5/EL5 data for curves.","Brans lists equivalents: 4654(P), 4654K, 4689(P), EL12/375, EL12spez, EL35, EL50."],"references":["https://frank.pocnet.net/sheets/204/a/AL5.pdf"],"source_urls":{"r_type":null,"tdsl":null,"radiomuseum":"https://www.radiomuseum.org/tubes/tube_al5375.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"AL5","reason":"Standard version rated to 275 V — same P8A base and pinout","has_detail_page":true},{"type_number":"EL12/375","reason":"6.3 V heater version with Y8A base — different base, not pin-compatible","has_detail_page":true},{"type_number":"EL5","reason":"6.3 V heater version of AL5 — same characteristics except heater","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Control Grid (g1)","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 (g2)","function_code":"g2","notes":null},{"pin_number":"6","function":"Metallization","function_code":"ia","notes":null},{"pin_number":"7","function":"Suppressor Grid (g3, 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":"4","numeric_value":"4","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"2","numeric_value":"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":"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":"18","numeric_value":"18","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":"0.7","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":"275","numeric_value":"275","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-14","numeric_value":"-14","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":"7","numeric_value":"7","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"22000","numeric_value":"22000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"7.5","numeric_value":"7.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"175","numeric_value":"175","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"9.1","numeric_value":"9.1","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"3500","numeric_value":"3500","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T12:35:42.174Z"}