{"type_number":"13D1","canonical_url":"https://tubeofile.com/tubes/13D1","manufacturer":"Brimar","tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Octal","description":"Medium-mu twin triode with separate cathodes and 25V heater. Brimar industrial type designed for aircraft and industrial equipment where reliability is critical. Supersedes the 25SN7GT and is a direct replacement for it. Characteristics are nominally identical to the 6SN7GT except for heater rating.","is_directly_heated":false,"completeness":"high","notes":["Brimar datasheet states: characteristics are nominally the same as for the type 6SN7GT. Refer to 6SN7GT curves for further information.","25V 0.15A heater — not interchangeable with 6SN7GT (6.3V) without heater supply changes.","Maximum ratings below are taken from the 6SN7GT family data (JJ Electronic), as the Brimar 13D1 datasheet references the 6SN7GT for full characteristics and does not list separate absolute maximum ratings."],"references":["https://frank.pocnet.net/sheets/155/1/13D1.pdf","https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/6sn7/6SN7.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=13D1","radiomuseum":"https://www.radiomuseum.org/tubes/tube_13d1_brimar.html"},"raw_equivalents":["25SN7GT","CV423","1633","7N7"],"equivalents":[{"type_number":"1633","equivalence_type":"direct","notes":null},{"type_number":"7N7","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"12SN7WGT","reason":"Same octal pinout as 6SN7GT but 12.6V heater vs 25V for 13D1","has_detail_page":true},{"type_number":"12SX7GT","reason":"Same octal pinout as 6SN7GT but 12.6V heater vs 25V for 13D1","has_detail_page":false},{"type_number":"14N7","reason":"Same electricals as 6SN7GT but Loctal base vs Octal for 13D1","has_detail_page":false},{"type_number":"6SN7GT","reason":"Same electricals but 6.3V heater — 13D1 has 25V heater","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Control Grid (section 2)","function_code":"g1_2","notes":null},{"pin_number":"2","function":"Anode (section 2)","function_code":"a2","notes":null},{"pin_number":"3","function":"Cathode (section 2)","function_code":"k2","notes":null},{"pin_number":"4","function":"Control Grid (section 1)","function_code":"g1_1","notes":null},{"pin_number":"5","function":"Anode (section 1)","function_code":"a1","notes":null},{"pin_number":"6","function":"Cathode (section 1)","function_code":"k1","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Heater","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"25","numeric_value":"25","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.15","numeric_value":"0.15","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"450","numeric_value":"450","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"5","numeric_value":"5","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"20","numeric_value":"20","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"100","numeric_value":"100","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"1","numeric_value":"1","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":"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":"4.1","numeric_value":"4.1","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"2.6","numeric_value":"2.6","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"0.8","numeric_value":"0.8","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T19:00:52.958Z"}