{"type_number":"EF86","canonical_url":"https://tubeofile.com/tubes/EF86","manufacturer":"Philips","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Noval","description":"Low-noise AF pentode for use as RC-coupled voltage amplifier, particularly in early stages of high-gain audio amplifiers, microphone pre-amplifiers, and magnetic tape recorders. Replaced EF37A and EF40.","is_directly_heated":false,"completeness":"high","notes":["Pins 1 and 7 are internal metallic shields for hum and noise reduction — must be grounded for lowest noise performance.","Pin 2 (g3/suppressor) is internally connected to cathode; separate pin allows external connection if needed.","Equivalent noise voltage: approx. 2 µV (25–10,000 Hz bandwidth) at Vb = 250 V, Ra = 100 kΩ.","Vhk_max is asymmetric: 100 V (cathode positive of heater) / 50 V (cathode negative of heater).","Rg_max depends on anode dissipation: 10 MΩ for Wa < 0.2 W, 3 MΩ for Wa > 0.2 W. The 10 MΩ figure applies to typical low-level audio preamp use.","PF86 (series heater) and UF86 (12.6 V heater) are pin-compatible variants with different heater ratings.","Triode connection operating data on Philips datasheet page 3: three RC-coupled amplifier configurations documented at supply voltages from 100–400 V. Small-signal triode characteristics (μ, gm, ra) from Tom Schlangen measurements, consistent with Philips stage-gain data."],"references":["https://tube-data.com/sheets/030/e/EF86.pdf"],"source_urls":{"r_type":"http://www.r-type.org/exhib/aai0113.htm","tdsl":"http://tdsl.duncanamps.com/show.php?des=EF86","radiomuseum":"https://www.radiomuseum.org/tubes/tube_ef86.html"},"raw_equivalents":["6267","6BK8","6F22","CV2901","Z729","EF806S","6J32P","CV4086"],"equivalents":[{"type_number":"6J32P","equivalence_type":"direct","notes":null},{"type_number":"CV4086","equivalence_type":"direct","notes":null},{"type_number":"EF806S","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"PF86","reason":"Series-heater version (25V/0.3A) — not compatible with 6.3V parallel heater circuits","has_detail_page":true},{"type_number":"UF86","reason":"12.6V heater variant — different heater requirements","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Screen Grid","function_code":"g2","notes":null},{"pin_number":"2","function":"Internal Shield","function_code":"ia","notes":null},{"pin_number":"3","function":"Cathode","function_code":"k","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","function_code":"a","notes":null},{"pin_number":"7","function":"Internal Shield","function_code":"ia","notes":null},{"pin_number":"8","function":"Suppressor Grid (g3, internally connected to cathode)","function_code":"g3","notes":null},{"pin_number":"9","function":"Control Grid","function_code":"g1","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":"0.2","numeric_value":"0.2","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Pentode","tube_type_key":"ss_pentode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"200","numeric_value":"200","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"1.0","numeric_value":"1","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"0.2","numeric_value":"0.2","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"6","numeric_value":"6","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":"10","numeric_value":"10","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":"140","numeric_value":"140","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-2","numeric_value":"-2","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"3.0","numeric_value":"3","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"0.6","numeric_value":"0.6","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"2500000","numeric_value":"2500000","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":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"<0.05","numeric_value":null,"unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"3.8","numeric_value":"3.8","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"5.3","numeric_value":"5.3","unit":"pF","param_group":"capacitances"},{"key":"noise","display_name":"Equivalent Input Noise Voltage","value":"2","numeric_value":"2","unit":"µV","param_group":"noise_rf"},{"key":null,"display_name":"Req (Equivalent Noise Resistance)","value":"<100000","numeric_value":null,"unit":"Ω","param_group":null},{"key":null,"display_name":"μg2g1","value":"38","numeric_value":"38","unit":"—","param_group":null}]},{"section_number":2,"section_label":"Triode Strapped","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"200","numeric_value":"200","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"1.0","numeric_value":"1","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"6","numeric_value":"6","unit":"mA","param_group":"absolute_max"},{"key":"ra","display_name":"Anode Resistance","value":"16500","numeric_value":"16500","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":"33","numeric_value":"33","unit":"—","param_group":"typical_operating"}]}],"synced_at":"2026-04-07T19:08:10.204Z"}