{"type_number":"7N7","canonical_url":"https://tubeofile.com/tubes/7N7","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Loctal","description":"Medium-mu twin triode in loctal (lock-in) construction. Designed for use as a phase inverter or voltage amplifier. Electrically equivalent to the early 6SN7GT but with a Loctal base. Registered April 1940, predating the 6SN7GT.","is_directly_heated":false,"completeness":"high","notes":["The 7N7 was registered in April 1940, predating the more famous 6SN7GT. It is electrically identical to early 6SN7 versions but never received the uprated maximum ratings (Va_max, Pa_max) that later 6SN7GTA/GTB variants did.","Maximum plate voltage is 300V and maximum plate dissipation is 2.5W per section — significantly lower than later 6SN7GTB ratings (450V/5W). Use early 6SN7GT ratings when designing circuits.","The 14N7 is the 12.6V/0.3A series-string heater version. Pin functions are identical but heater wiring differs.","Sylvania rated the nominal heater voltage at 7.0V in their ratings section, though the typical operating voltage is 6.3V as with all other sources. The Sylvania heater current is listed as 0.640A vs Tung-Sol's 0.600A — a minor discrepancy between manufacturers."],"references":["https://frank.pocnet.net/sheets/127/7/7N7.pdf","https://frank.pocnet.net/sheets/084/7/7N7.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=7N7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_7n7.html"},"raw_equivalents":["14N7","CV898","13D1"],"equivalents":[{"type_number":"13D1","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"12SX7GT","reason":"Same electrical characteristics (mu=20, gm=2.6 mA/V) but Octal base — requires adapter or rewiring","has_detail_page":false},{"type_number":"6CG7","reason":"Similar electricals but Noval (9-pin) base","has_detail_page":true},{"type_number":"6F8G","reason":"Predecessor with similar electricals but Octal base with top-cap grid on one section — different pin topology","has_detail_page":true},{"type_number":"6FQ7","reason":"Similar electricals but Noval (9-pin) base","has_detail_page":false},{"type_number":"6SN7GT","reason":"Electrically identical but Octal base — requires adapter or rewiring","has_detail_page":false},{"type_number":"7AF7","reason":"Same Loctal base and pinout but lower mu (16 vs 20) and different heater current (0.3A vs 0.6A)","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Heater","function_code":"h","notes":null},{"pin_number":"2","function":"Cathode (section 2)","function_code":"k2","notes":null},{"pin_number":"3","function":"Anode (section 2)","function_code":"a2","notes":null},{"pin_number":"4","function":"Control Grid (section 2)","function_code":"g1_2","notes":null},{"pin_number":"5","function":"Control Grid (section 1)","function_code":"g1_1","notes":null},{"pin_number":"6","function":"Anode (section 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Cathode (section 1)","function_code":"k1","notes":null},{"pin_number":"8","function":"Heater","function_code":"h","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":"0.6","numeric_value":"0.6","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode (each section)","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"2.5","numeric_value":"2.5","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":"250","numeric_value":"250","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-8","numeric_value":"-8","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"9","numeric_value":"9","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"7700","numeric_value":"7700","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.6","numeric_value":"2.6","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"20","numeric_value":"20","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"3","numeric_value":"3","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"3.4","numeric_value":"3.4","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"2","numeric_value":"2","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:32:39.664Z"}