{"type_number":"8BQ5","canonical_url":"https://tubeofile.com/tubes/8BQ5","manufacturer":null,"tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Noval","description":"AF output power pentode; 8.4V heater variant of the EL84/6BQ5 for series-string television receivers. Electrically identical to the EL84 except for heater voltage (8.4V at 0.45A instead of 6.3V at 0.76A).","is_directly_heated":false,"completeness":"high","notes":["8.4V / 0.45A heater for series-string TV receiver heater chains. Electrically identical to EL84/6BQ5 in all other respects.","Not interchangeable with EL84/6BQ5 without heater circuit modification.","Brans Vademecum lists equivalents: 16GK6, 29GK6, 6BQ5, 6GK6, 6P15, 7189A, 8GK6, EL172, EL20, EL22, EL84 — many of these have different heater voltages and are not direct drop-in replacements."],"references":["https://tdsl.duncanamps.com/show.php?des=8BQ5","https://www.radiomuseum.org/tubes/?tube=8BQ5"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=8BQ5","radiomuseum":"https://www.radiomuseum.org/tubes/tube_8bq5.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"6BQ5","reason":"American designation for EL84 — same electrical characteristics but 6.3V heater","has_detail_page":false},{"type_number":"8GK6","reason":"Similar 8.4V heater pentode listed as equivalent in Brans","has_detail_page":true},{"type_number":"EL84","reason":"Same electrical characteristics but 6.3V heater — not a drop-in in 8.4V series-string circuits","has_detail_page":true},{"type_number":"UEL84","reason":"100mA series-string heater version of EL84 — different heater voltage","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"2","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"3","function":"Cathode (g3 internally connected)","function_code":"k","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Heater","function_code":"h","notes":null},{"pin_number":"6","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"7","function":"Anode (Plate)","function_code":"a","notes":null},{"pin_number":"8","function":"Internal Connection","function_code":"ia","notes":null},{"pin_number":"9","function":"Screen Grid (g2)","function_code":"g2","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"8.4","numeric_value":"8.4","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.45","numeric_value":"0.45","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":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"12","numeric_value":"12","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":"65","numeric_value":"65","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"100","numeric_value":"100","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"1","numeric_value":"1","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":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-7.3","numeric_value":"-7.3","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"48","numeric_value":"48","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"5.5","numeric_value":"5.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"38000","numeric_value":"38000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"11.3","numeric_value":"11.3","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"135","numeric_value":"135","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"5.7","numeric_value":"5.7","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"4500","numeric_value":"4500","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.5","numeric_value":"0.5","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"10.8","numeric_value":"10.8","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"6.5","numeric_value":"6.5","unit":"pF","param_group":"capacitances"}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"12","numeric_value":"12","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"65","numeric_value":"65","unit":"mA","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":"-9.5","numeric_value":"-9.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"35","numeric_value":"35","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"2000","numeric_value":"2000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"8.5","numeric_value":"8.5","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"17","numeric_value":"17","unit":"—","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"270","numeric_value":"270","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"1.95","numeric_value":"1.95","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"3500","numeric_value":"3500","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T12:34:33.069Z"}