{"type_number":"6A5G","canonical_url":"https://tubeofile.com/tubes/6A5G","manufacturer":"Sylvania","tube_type_key":"power_triode","tube_type_display_name":"Power Triode","base_name":"Octal","description":"Power amplifier triode, indirectly heated, designed for the same service as types 6A3 and 6B4G. Octal base with characteristics identical to the 6B4G except for Class A power rating of 3.75 watts. Introduced by Sylvania (1937).","is_directly_heated":false,"completeness":"medium","notes":["Sylvania datasheet (January 4, 1937, from RMA release #101). Described as heater-type power amplifier triode.","All eight pins are present but pin numbers 1, 4, and 6 are not connected. The tube is free from hum so no potentiometer is required for hum balance.","Grid circuit resistance: 0.5 MΩ max for self-biased arrangement, 10 kΩ for fixed bias.","Raytheon data lists as 'PR AMP CL A' with mu=4.2, gm=5350 µmhos, load=8000 Ω at Va=300 V, Vg=-18.","Sylvania datasheet gives mu=4.2, gm=5250 µmhos, ra=800 Ω at Va=250 V, Vg=-45 for Class A. Push-pull Class AB values: Va=325 V, Pout=10-15 W (fixed/self bias)."],"references":["https://frank.pocnet.net/sheets/201/6/6A5G.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6A5G","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6a5g.html"},"raw_equivalents":["6A5"],"equivalents":[],"similar":[{"type_number":"2A3","reason":"Similar power triode but 2.5V filament on 4-pin UX base — different base and heater voltage","has_detail_page":true},{"type_number":"6A3","reason":"Directly heated triode with same ratings and applications — NOT a drop-in due to directly vs indirectly heated cathode. Sylvania states 6A5G ratings and characteristics are identical to 6B4G except for Class A power rating.","has_detail_page":false},{"type_number":"6B4G","reason":"Directly heated triode with identical ratings except different Class A power rating — NOT drop-in due to directly vs indirectly heated cathode","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":"Plate (Anode)","function_code":"a","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Grid","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}],"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":"1.0","numeric_value":"1","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","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":"Vg","display_name":"Grid 1 Bias Voltage","value":"-45","numeric_value":"-45","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"60","numeric_value":"60","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"800","numeric_value":"800","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"5.25","numeric_value":"5.25","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"4.2","numeric_value":"4.2","unit":"—","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"3.75","numeric_value":"3.75","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"2500","numeric_value":"2500","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"16","numeric_value":"16","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"7","numeric_value":"7","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"5","numeric_value":"5","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:14:31.184Z"}