{"type_number":"M8161","canonical_url":"https://tubeofile.com/tubes/M8161","manufacturer":"Mullard","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"B7G","description":"Special quality variable-mu (remote-cutoff) RF pentode. B7G miniature 7-pin base. Mullard design with tightly controlled electrical parameters for use in equipment where mechanical vibration and shocks are unavoidable. Equivalent to 6065/CV4015.","is_directly_heated":false,"completeness":"high","notes":["M8161 is the Mullard special quality designation; 6065 is the RTMA type; CV4015 is the military designation.","Philips interchange confirms: M8161 = CV4015 = 6065.","Amplification factor mu_g2/g1 = 30 (from M8161 datasheet).","Grid 3 cutoff voltage: Vg1 = -7.0 V at Ia = 50 uA.","Group quality level testing includes fatigue tests, shock tests, and stability life tests.","Brans lists many equivalents including W77, VP4A, EF177, UF41."],"references":["https://frank.pocnet.net/sheets/129/m/M8161.pdf"],"source_urls":{"r_type":null,"tdsl":null,"radiomuseum":"https://www.radiomuseum.org/tubes/tube_m8161.html"},"raw_equivalents":["6065","CV4015"],"equivalents":[{"type_number":"6065","equivalence_type":"direct","notes":null},{"type_number":"CV4015","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"EF85","reason":"Similar variable-mu RF pentode on B9A base — not pin-compatible","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"2","function":"Cathode (and internal shield)","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":"Anode","function_code":"a","notes":null},{"pin_number":"6","function":"Suppressor Grid (g3, internal shield)","function_code":"g3","notes":null},{"pin_number":"7","function":"Screen Grid (g2)","function_code":"g2","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":"0.2","numeric_value":"0.2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"ss_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"500","numeric_value":"500","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":"3","numeric_value":"3","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"0.7","numeric_value":"0.7","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"14","numeric_value":"14","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"150","numeric_value":"150","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":"200","numeric_value":"200","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"200","numeric_value":"200","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-2.5","numeric_value":"-2.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"8.25","numeric_value":"8.25","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"2.1","numeric_value":"2.1","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"900000","numeric_value":"900000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.45","numeric_value":"2.45","unit":"mA/V","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.015","numeric_value":"0.015","unit":"pF","param_group":"capacitances"},{"key":null,"display_name":"Grid 1 Cutoff Voltage (100:1 gm reduction)","value":"-27","numeric_value":"-27","unit":"V","param_group":null},{"key":null,"display_name":"Anode Voltage (max, operating)","value":"300","numeric_value":"300","unit":"V","param_group":null}]}],"synced_at":"2026-04-07T19:09:09.157Z"}