{"type_number":"5751","canonical_url":"https://tubeofile.com/tubes/5751","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Noval","description":"Special-quality high-mu twin triode designed for dependable performance under shock and vibration. Two identical triode sections with individual cathode connections. Similar to 12AX7 but with reduced mu (70 vs 100) and increased heater current for improved reliability.","is_directly_heated":false,"completeness":"high","notes":["Designed for military/avionics applications requiring resistance to shock (600g impact) and vibration (2.5g at 25 Hz). Features doubled bottom mica and dual top micas for mechanical stability.","The 5751WI is the full military specification version (MIL-E-1/746) with additional sweep-frequency vibration testing; electrically identical to the 5751.","Can substitute for 12AX7/ECC83 in parallel-heater circuits with approximately 30% gain reduction. Not a drop-in equivalent due to different mu, bias point, and heater current.","RCA characteristics range: mu 55-85, gm 900-1600 µmhos, Ia 0.4-1.8 mA at Va=250V. Wider tolerance range than typical receiving tubes reflects the military emphasis on reliability over tight parameter matching.","Registered October 1949 (Electron Tube Registration List). First documented by RCA, October 1953."],"references":["https://frank.pocnet.net/sheets/127/5/5751.pdf","https://frank.pocnet.net/sheets/049/5/5751.pdf"],"source_urls":{"r_type":"https://www.r-type.org/exhib/abs0013.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=5751","radiomuseum":"https://www.radiomuseum.org/tubes/tube_5751.html"},"raw_equivalents":["CK5751","GL5751","5751WA","CV4017","CV8312","Z1764"],"equivalents":[],"similar":[{"type_number":"12AX7","reason":"Pin-compatible but electrically different: mu=100 vs 70, Pa_max=1.0W vs 0.8W, heater current 0.3A vs 0.35A. Usable as a substitute in parallel-heater circuits with gain increase.","has_detail_page":true},{"type_number":"7025","reason":"Low-noise 12AX7 variant. Pin-compatible but mu=100 vs 70.","has_detail_page":false},{"type_number":"ECC83","reason":"European designation of 12AX7. Pin-compatible but mu=100 vs 70.","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Anode 2 (Triode section 2)","function_code":"a2","notes":null},{"pin_number":"2","function":"Control Grid 2 (Triode section 2)","function_code":"g1_2","notes":null},{"pin_number":"3","function":"Cathode 2 (Triode section 2)","function_code":"k2","notes":null},{"pin_number":"4","function":"Heater","function_code":"h","notes":null},{"pin_number":"5","function":"Heater","function_code":"h","notes":null},{"pin_number":"6","function":"Anode 1 (Triode section 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Control Grid 1 (Triode section 1)","function_code":"g1_1","notes":null},{"pin_number":"8","function":"Cathode 1 (Triode section 1)","function_code":"k1","notes":null},{"pin_number":"9","function":"Heater center tap","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"12.6","numeric_value":"12.6","unit":"V","param_group":"heater"},{"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":"0.175","numeric_value":"0.175","unit":"A","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.35","numeric_value":"0.35","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":"330","numeric_value":"330","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"0.8","numeric_value":"0.8","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"4.0","numeric_value":"4","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":"0.5","numeric_value":"0.5","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":"-3","numeric_value":"-3","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"1.0","numeric_value":"1","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"58000","numeric_value":"58000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"1.2","numeric_value":"1.2","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"70","numeric_value":"70","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"1.4","numeric_value":"1.4","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"1.4","numeric_value":"1.4","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"0.5","numeric_value":"0.5","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:11:17.980Z"}