{"type_number":"VT-52","canonical_url":"https://tubeofile.com/tubes/VT-52","manufacturer":"Raytheon","tube_type_key":"power_triode","tube_type_display_name":"Power Triode","base_name":"UX4","description":"Military transmitting triode with electrode structure derived from the standard 45; designed for aircraft radio sets (BC-230/430) with 7V filament for vehicle electrical systems","is_directly_heated":true,"completeness":"medium","notes":["The VT-52 is a military 'special 45' variant with a 7V three-section filament (vs 2.5V for the standard 45). It is NOT a drop-in replacement for the 45 due to the different filament voltage.","Filament specifications vary slightly between manufacturers: Raytheon rates 7V at 1.2A; Sylvania and Brimar rate 7V at 1.18A.","Originally designed for the BC-230 aircraft transmitter (SCR-183 radio set); the 7V filament was intended for 6.3V vehicle battery systems with voltage variation in flight.","Many VT-52s are tested and operated at 6.3V in audio applications, though the rated filament voltage is 7V.","Amplification factor varies significantly between manufacturers: Raytheon 3.6, Sylvania 3.8, Brimar 2.6. All agree on ra = 1800 ohms and Pa_max = 10W.","The EIA designation 2C45 was reportedly never formally registered. Complete manufacturer datasheets are considered largely lost; specifications sourced from partial datasheets reproduced in collector references.","DHT tube: the filament serves as the cathode; there is no heater-cathode isolation.","The British VT52 (without hyphen) on radiomuseum.org refers to the Philips EL32 pentode — a completely different tube. The American VT-52 is the 45 special."],"references":["https://jacmusic.com/techcorner/ARTICLES/English/Portraits/VT52/index.html","https://www.radiomuseum.org/tubes/tube_vt52_usa.html","https://vt52.com/info/vt52/vt52_tester.html"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=VT52","radiomuseum":"https://www.radiomuseum.org/tubes/tube_vt52_usa.html"},"raw_equivalents":["2C45","CV596","38142","6K6","EL32"],"equivalents":[{"type_number":"6K6","equivalence_type":"direct","notes":null},{"type_number":"EL32","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"45","reason":"Military variant with 7V filament vs standard 2.5V — NOT a drop-in replacement","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Filament (f-)","function_code":"h","notes":null},{"pin_number":"2","function":"Plate (Anode)","function_code":"a","notes":null},{"pin_number":"3","function":"Grid","function_code":"g1","notes":null},{"pin_number":"4","function":"Filament (f+)","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"7","numeric_value":"7","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"1.2","numeric_value":"1.2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"power_triode","specs":[{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"10","numeric_value":"10","unit":"W","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"220","numeric_value":"220","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-40","numeric_value":"-40","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"28","numeric_value":"28","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1800","numeric_value":"1800","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.0","numeric_value":"2","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"3.6","numeric_value":"3.6","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T19:09:43.152Z"}