{"type_number":"KT30","canonical_url":"https://tubeofile.com/tubes/KT30","manufacturer":"MO Valve Co.","tube_type_key":"beam_tetrode","tube_type_display_name":"Beam Tetrode","base_name":"B7G","description":"Beam power tetrode with 13 V / 0.3 A heater; indirectly heated. Manufactured by MO Valve Co. (Marconi-Osram), UK, from 1934. Designed for battery-operated equipment with series-string heater operation. British 7-pin (M7A) base.","is_directly_heated":false,"completeness":"medium","notes":["13 V heater at 0.3 A — designed for series-string heater operation in battery receivers.","British 7-pin (M7A) base — an early British base type, not the later B7G miniature.","Very early beam tetrode design from 1934. Found in only 2 radio models at Radiomuseum.","Class A SE at Va=250V, Vg2=250V: Ia=40 mA, Ig2=7 mA, gm=3.9 mA/V, Rk=260 Ω, rl=7500 Ω, Pout=2.7 W."],"references":["https://tdsl.duncanamps.com/show.php?des=KT30","https://www.radiomuseum.org/tubes/?tube=KT30"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=KT30","radiomuseum":"https://www.radiomuseum.org/tubes/tube_kt30.html"},"raw_equivalents":["Y13","CV3519"],"equivalents":[],"similar":[],"pins":[{"pin_number":"1","function":"Anode","function_code":"a","notes":null},{"pin_number":"2","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"3","function":"Control Grid (g1)","function_code":"g1","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":"Cathode","function_code":"k","notes":null},{"pin_number":"7","function":"Beam Plates (internally connected to cathode)","function_code":"bp","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"13","numeric_value":"13","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.3","numeric_value":"0.3","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Beam Tetrode","tube_type_key":"beam_tetrode","specs":[{"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":"-12","numeric_value":"-12","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"40","numeric_value":"40","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"7","numeric_value":"7","unit":"mA","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"3.9","numeric_value":"3.9","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"260","numeric_value":"260","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"2.7","numeric_value":"2.7","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"7500","numeric_value":"7500","unit":"Ω","param_group":"output"}]}],"synced_at":"2026-04-07T12:49:00.716Z"}