{"type_number":"6D6","canonical_url":"https://tubeofile.com/tubes/6D6","manufacturer":"RCA","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"UX6","description":"Variable-mu (remote cutoff) RF pentode, predecessor to the 6K7. Uses a 6-pin base with grid cap on top. Designed for use with AVC in RF and IF amplifier stages. Indirectly heated.","is_directly_heated":false,"completeness":"high","notes":["The 6D6 uses a 6-pin base with the control grid brought out to a top cap. It was introduced in the early 1930s and widely used in pre-war superheterodyne receivers.","Typical operating conditions at Va=250V, Vg2=100V, Vg1=-3V: Ia=8.2mA, Ig2=2.0mA, Rp=800kΩ, Gm=1600 umhos.","Maximum ratings: plate voltage 300V, screen voltage 150V, plate dissipation 2.25W.","The 6D6 was superseded by the 6K7 (Octal base) and later by the 6SK7 (Octal, no top cap), and eventually by the 6BA6 (miniature B7G)."],"references":["https://frank.pocnet.net/sheets/049/6/6D6.pdf","https://tdsl.duncanamps.com/show.php?des=6D6"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6D6","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6d6.html"},"raw_equivalents":["CV1083","VT-73"],"equivalents":[],"similar":[{"type_number":"6K7","reason":"Successor remote-cutoff pentode with similar characteristics but Octal base — not pin-compatible","has_detail_page":true},{"type_number":"6SK7","reason":"Later remote-cutoff pentode, Octal base, no top cap — not pin-compatible","has_detail_page":true},{"type_number":"78","reason":"Same tube with 6.3V heater in identical UX6 base — often listed as direct equivalent but some sources differentiate them","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Plate","function_code":"a","notes":null},{"pin_number":"2","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"3","function":"Suppressor Grid (g3) / Cathode","function_code":"g3","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Cathode","function_code":"k","notes":null},{"pin_number":"6","function":"Heater","function_code":"h","notes":null},{"pin_number":"TC","function":"Control Grid (g1)","function_code":"g1","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":"0.3","numeric_value":"0.3","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":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"150","numeric_value":"150","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"2.25","numeric_value":"2.25","unit":"W","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":"100","numeric_value":"100","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-3","numeric_value":"-3","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"8.2","numeric_value":"8.2","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"2.0","numeric_value":"2","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"800000","numeric_value":"800000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.6","numeric_value":"1.6","unit":"mA/V","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:20:45.285Z"}