{"type_number":"KT63","canonical_url":"https://tubeofile.com/tubes/KT63","manufacturer":"Marconi-Osram","tube_type_key":"beam_tetrode","tube_type_display_name":"Beam Tetrode","base_name":"Octal","description":"Audio output beam tetrode, suitable for all A.C. receivers where medium power is required with high efficiency. Originally designated N63, introduced in 1937.","is_directly_heated":false,"completeness":"high","notes":["The KT63 is a beam tetrode while the 6F6 is a true pentode — they share the same pinout and similar characteristics but are not identical internally. The KT63 uses beam-forming plates instead of a suppressor grid.","Maximum ratings taken from RCA 6F6 datasheet as no GEC/Osram KT63 datasheet with explicit max ratings has been located. The Marconi datasheet specifies only 250V operating conditions and states 'Nominal Rating, see curve' for max dissipation.","Triode-strapped data from the Marconi KT63 datasheet: gm=2.4 mA/V, ra=3200 ohms. The 6F6 pentode gives slightly different triode figures (mu=6.8, gm=2.6 mA/V, ra=2600 ohms) due to structural differences.","TDSL lists Pout as 4.8W at Va=250V while the Marconi datasheet shows 3.0W — different datasheets report different output power figures depending on operating conditions and measurement criteria."],"references":["https://frank.pocnet.net/sheets/179/k/KT63.pdf","https://frank.pocnet.net/sheets/049/6/6F6.pdf","http://www.r-type.org/exhib/abh0254.htm"],"source_urls":{"r_type":"http://www.r-type.org/exhib/abh0254.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=KT63","radiomuseum":"https://www.radiomuseum.org/tubes/tube_kt63.html"},"raw_equivalents":["6F6G","ARP17","CV1186","CV1911","NR85"],"equivalents":[],"similar":[{"type_number":"KT30","reason":"Electrically similar MO Valve pentode but B5 (5-pin) base vs Octal — not pin-compatible","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Shell (Metallisation)","function_code":"ia","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Anode","function_code":"a","notes":null},{"pin_number":"4","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"5","function":"Control 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":"0.7","numeric_value":"0.7","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Beam Tetrode","tube_type_key":"beam_tetrode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"375","numeric_value":"375","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"285","numeric_value":"285","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"11","numeric_value":"11","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"3.75","numeric_value":"3.75","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"46","numeric_value":"46","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"90","numeric_value":"90","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":"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":"-16.5","numeric_value":"-16.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"34","numeric_value":"34","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":"80000","numeric_value":"80000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.5","numeric_value":"2.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"420","numeric_value":"420","unit":"Ω","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"3.0","numeric_value":"3","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"7000","numeric_value":"7000","unit":"Ω","param_group":"output"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.8","numeric_value":"0.8","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"9.8","numeric_value":"9.8","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"9.0","numeric_value":"9","unit":"pF","param_group":"capacitances"}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"power_triode","specs":[{"key":"Va","display_name":"Anode Voltage (typical)","value":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"3200","numeric_value":"3200","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.4","numeric_value":"2.4","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"7.7","numeric_value":"7.7","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:49:04.769Z"}