{"type_number":"6BQ7A","canonical_url":"https://tubeofile.com/tubes/6BQ7A","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Noval","description":"Medium-mu twin triode designed for use as a cascode radio-frequency amplifier in VHF television tuners. Characterized by high gain and low noise figure, with an internal shield providing isolation between the two triode sections.","is_directly_heated":false,"completeness":"high","notes":["Pin 9 (internal shield) should be grounded; with external shield (RETMA 315) connected to pin 9.","In cascode amplifier service with both sections in series, Va_max may be as high as 300 V under cutoff conditions.","4BQ7A (Vh=4.2V, Ih=0.6A) and 5BQ7A (Vh=5.6V, Ih=0.45A) are heater-voltage variants with controlled warm-up characteristics for series-string television receivers.","Replaced the 6BQ7 within two years of its introduction, offering approximately 12% higher gain with otherwise identical characteristics."],"references":["https://frank.pocnet.net/sheets/049/6/6BQ7A.pdf","https://frank.pocnet.net/sheets/093/6/6BQ7A.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6BQ7A","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6bq7a.html"},"raw_equivalents":["6BQ7","6BZ7","6BS8","6BC8","6BZ8","6BX8","6HK8","X155","ECC180","CV5365","4BQ7A","5BQ7A","6CH7","6CX7"],"equivalents":[],"similar":[{"type_number":"6BK7","reason":"Semi-remote cutoff twin triode on same 9AJ base — may not work in all circuits per Sams substitution guide","has_detail_page":true},{"type_number":"6BK7A","reason":"Semi-remote cutoff twin triode on same 9AJ base — may not work in all circuits per Sams substitution guide","has_detail_page":false},{"type_number":"6BK7B","reason":"Semi-remote cutoff twin triode on same 9AJ base — may not work in all circuits per Sams substitution guide","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Plate (Section 2)","function_code":"a2","notes":null},{"pin_number":"2","function":"Grid (Section 2)","function_code":"g1_2","notes":null},{"pin_number":"3","function":"Cathode (Section 2)","function_code":"k2","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":"Plate (Section 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Grid (Section 1)","function_code":"g1_1","notes":null},{"pin_number":"8","function":"Cathode (Section 1)","function_code":"k1","notes":null},{"pin_number":"9","function":"Internal Shield","function_code":"ia","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":"0.4","numeric_value":"0.4","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"2.0","numeric_value":"2","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"20","numeric_value":"20","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"200","numeric_value":"200","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"0.5","numeric_value":"0.5","unit":"MΩ","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"150","numeric_value":"150","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-6.5","numeric_value":"-6.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"9.0","numeric_value":"9","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"5900","numeric_value":"5900","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"6.4","numeric_value":"6.4","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"38","numeric_value":"38","unit":"—","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"220","numeric_value":"220","unit":"Ω","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"1.2","numeric_value":"1.2","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"2.6","numeric_value":"2.6","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"1.2","numeric_value":"1.2","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:18:43.709Z"}