{"type_number":"EL34","canonical_url":"https://tubeofile.com/tubes/EL34","manufacturer":"Philips","tube_type_key":"power_pentode","tube_type_display_name":"Power Pentode","base_name":"Octal","description":"AF output power pentode; indirect heated. Developed by Philips in 1949, widely used in hi-fi audio and guitar amplifiers.","is_directly_heated":false,"completeness":"high","notes":["In triode connection (g2 strapped to anode), Va_max increases to 600 V but combined Pa+Pg2 dissipation is limited to 30 W (Va ≤ 500 V) or 15 W (Va = 600 V).","PP triode (Rk bypassed): Vb = 430 V, Va = 400 V, Ra-a = 5 kΩ, Rk = 440 Ω/valve delivers 19 W at 1.8% THD. With Rk unbypassed: Ra-a = 10 kΩ delivers 14 W at 0.4% THD.","Pentode characteristics measured at Va = 250 V, Vg2 = 250 V, Vg1 = 0 V: Ia = 100 mA, Ig2 = 15 mA, gm = 11 mA/V, ra = 15 kΩ, μg2g1 = 11. Triode characteristics at Va = 250 V: Ia = 70 mA, Vg1 = -15.5 V, gm = 11.5 mA/V, ra = 910 Ω, μ = 10.5."],"references":["https://tube-data.com/sheets/129/e/EL34.pdf","https://tdsl.duncanamps.com/show.php?des=EL34"],"source_urls":{"r_type":"http://www.r-type.org/exhib/aaa0098.htm","tdsl":"http://tdsl.duncanamps.com/show.php?des=EL34","radiomuseum":"https://www.radiomuseum.org/tubes/tube_el34.html"},"raw_equivalents":["6CA7","E34L","EL34B","EL34G","CV1741","6P27S","7534"],"equivalents":[],"similar":[{"type_number":"6550","reason":"Beam tetrode with same Octal pinout. Often used interchangeably but EL34 is a true pentode with suppressor grid on pin 1, while 6550 has beam plates — different internal topology and somewhat different characteristics.","has_detail_page":true},{"type_number":"EL37","reason":"Same Octal base pentode, mutually listed as equivalent by Brans. Earlier Mullard design with slightly different characteristics. Verify ratings before substitution.","has_detail_page":true},{"type_number":"KT77","reason":"GEC beam tetrode on same Octal pinout — pin 1 is NC (beam plates) vs suppressor grid on EL34, different internal construction","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Suppressor Grid (g3)","function_code":"g3","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":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"5","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"6","function":"No Connection","function_code":"nc","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"8","function":"Cathode","function_code":"k","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":"1.5","numeric_value":"1.5","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"power_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"800","numeric_value":"800","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"500","numeric_value":"500","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"25","numeric_value":"25","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"8","numeric_value":"8","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"150","numeric_value":"150","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":"0.7","numeric_value":"0.7","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":"Vs","display_name":"Screen Voltage (typical)","value":"265","numeric_value":"265","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-13.5","numeric_value":"-13.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"100","numeric_value":"100","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"14.9","numeric_value":"14.9","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"17000","numeric_value":"17000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"12.5","numeric_value":"12.5","unit":"mA/V","param_group":"typical_operating"},{"key":"Pout","display_name":"Output Power","value":"11","numeric_value":"11","unit":"W","param_group":"output"},{"key":"rl","display_name":"Load Impedance","value":"2000","numeric_value":"2000","unit":"Ω","param_group":"output"}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"power_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"600","numeric_value":"600","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"30","numeric_value":"30","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"150","numeric_value":"150","unit":"mA","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":"-15.5","numeric_value":"-15.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"70","numeric_value":"70","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"910","numeric_value":"910","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"11.5","numeric_value":"11.5","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"10.5","numeric_value":"10.5","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T12:44:08.909Z"}