{"type_number":"6AC7","canonical_url":"https://tubeofile.com/tubes/6AC7","manufacturer":"Tung-Sol","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Octal","description":"Sharp-cutoff RF pentode in metal shell (MT8) with Octal base. High ratio of transconductance to plate current, with low capacitance. Designed for high-gain amplifier circuits. Also known as 1852.","is_directly_heated":false,"completeness":"medium","notes":["The 6AC7/1852 features exceptionally high transconductance (9000 umhos) with only 10mA plate current, making it ideal for high-gain RF and IF stages.","Two operating conditions: Condition 1 (fixed screen supply, sharp cutoff) and Condition 2 (series screen resistor 60kΩ, extended cutoff for AGC applications).","Metal shell with internal shield connected to pin 1. Suppressor (grid 3) should be connected to ground to minimize feedback."],"references":["https://frank.pocnet.net/sheets/127/6/6AC7.pdf","https://tdsl.duncanamps.com/show.php?des=6AC7"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=6AC7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_6ac7.html"},"raw_equivalents":["1852","6AC7A","CV660","CV747","CV846","CV849","VT-112"],"equivalents":[],"similar":[{"type_number":"6AG5","reason":"Similar sharp-cutoff pentode but B7G base — not pin-compatible","has_detail_page":true},{"type_number":"6J4","reason":"Soviet 6J4 (6Ж4) listed as equivalent — check pinout compatibility","has_detail_page":true},{"type_number":"6SJ7","reason":"Similar sharp-cutoff pentode on Octal base but lower gm (1650 vs 9000 umhos)","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Shell (Internal Shield)","function_code":"shell","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":"Grid 2 (Screen)","function_code":"g2","notes":null},{"pin_number":"5","function":"Grid 3 (Suppressor)","function_code":"g3","notes":null},{"pin_number":"6","function":"Cathode","function_code":"k","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Grid 1 (Control Grid)","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":"0.45","numeric_value":"0.45","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":"Vg2_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":"3","numeric_value":"3","unit":"W","param_group":"absolute_max"},{"key":"Pg2_max","display_name":"Screen Dissipation (max)","value":"0.38","numeric_value":"0.38","unit":"W","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":"Va","display_name":"Anode Voltage (typical)","value":"300","numeric_value":"300","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"0","numeric_value":"0","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"10","numeric_value":"10","unit":"mA","param_group":"typical_operating"},{"key":"Vg2","display_name":"Screen Voltage","value":"150","numeric_value":"150","unit":"V","param_group":"typical_operating"},{"key":"mAg2","display_name":"Screen Current","value":"2.5","numeric_value":"2.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1000000","numeric_value":"1000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"9","numeric_value":"9","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":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"11","numeric_value":"11","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"5","numeric_value":"5","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:14:47.334Z"}