{"type_number":"6CK4","canonical_url":"https://tubeofile.com/tubes/6CK4","manufacturer":"RCA","tube_type_key":"power_triode","tube_type_display_name":"Power Triode","base_name":"Octal","description":"Indirectly heated low-mu power triode designed as a vertical-deflection output tube in television receivers. With mu of 6.6, plate resistance of 1200 Ω and 12W plate dissipation, it has found a second life as a single-ended audio output tube delivering modest power with very low output impedance. Octal base (8JB basing).","is_directly_heated":false,"completeness":"high","notes":["Originally designed for vertical-deflection output in 525-line, 30-frame TV systems. Maximum ratings for this service: Va=550V DC, Va_peak=2000V, Vg_peak=-250V, Ik_peak=350mA, Ik_avg=100mA.","The Class A amplifier operating point (Va=250V, Vg=-28V, Ia=40mA) is the recommended audio operating condition.","At grid volts = -38V with Va=100V, plate current for matching is 10 mA. Grid voltage for plate current = 125 mA at Va=100V, Vg=0V.","Low mu (6.6) means very low plate resistance (1200 Ω) yielding excellent damping factor when used as an audio output stage — desirable for direct-drive loudspeaker coupling.","Indirectly heated with unipotential cathode — can share a common 6.3V heater winding with signal tubes.","Pa_max of 12W allows approximately 3-4W of single-ended Class A audio output depending on load impedance and operating point."],"references":["https://frank.pocnet.net/sheets/049/6/6CK4.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6CK4","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6ck4.html"},"raw_equivalents":["6CK4A"],"equivalents":[],"similar":[{"type_number":"6AS7","reason":"Octal twin low-mu power triode (mu=2) — much lower mu and higher current capability, dual-section, different operating point","has_detail_page":true},{"type_number":"6BX7","reason":"Octal twin low-mu power triode (mu=10) — two sections can be paralleled for similar Pa class, but different mu and dual-section construction","has_detail_page":true},{"type_number":"6Y6","reason":"Octal beam tetrode often triode-strapped for similar applications — different structure (beam tetrode vs true triode) and higher mu when triode-connected","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Grid","function_code":"g1","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Grid","function_code":"g1","notes":null},{"pin_number":"4","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"5","function":"Anode (Plate)","function_code":"a","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":"1.25","numeric_value":"1.25","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"550","numeric_value":"550","unit":"V","param_group":"absolute_max"},{"key":"Va_peak_max","display_name":"Peak Anode Voltage (max)","value":"2000","numeric_value":"2000","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":"100","numeric_value":"100","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":"-28","numeric_value":"-28","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"40","numeric_value":"40","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1200","numeric_value":"1200","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"5.5","numeric_value":"5.5","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"6.6","numeric_value":"6.6","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"6.5","numeric_value":"6.5","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"8","numeric_value":"8","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"1.8","numeric_value":"1.8","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:20:25.492Z"}