{"type_number":"EF860","canonical_url":"https://tubeofile.com/tubes/EF860","manufacturer":"RFT","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Noval","description":"Sharp-cutoff HF pentode with long life, designed for preamplifier stages in long-distance communication equipment. Noval (B9A) base. RFT (East German) design, corresponds to the EF800 type. Also produced as IF860 (20 V heater variant).","is_directly_heated":false,"completeness":"high","notes":["Designed for long life in telecommunications preamplifier stages.","Also available as IF860 with 20 V / 95 mA heater for series-string operation.","Life test end point: Ia < 6.7 mA, Ig2 < 1.6 mA, S < 5 mA/V, -Ig1 > 1 uA.","Self-bias only — Rk = 220 ohm (Vg1 approx. -2.75 V).","Screen grid amplification factor mu_g2/g1 = 50.","Tube was noted as being in development ('Rohre befindet sich in der Entwicklung')."],"references":["https://frank.pocnet.net/sheets/082/e/EF860.pdf"],"source_urls":{"r_type":null,"tdsl":null,"radiomuseum":"https://www.radiomuseum.org/tubes/tube_ef860.html"},"raw_equivalents":[],"equivalents":[],"similar":[{"type_number":"EF800","reason":"Corresponds to this type per RFT datasheet","has_detail_page":true},{"type_number":"EF86","reason":"Similar low-noise audio pentode on Noval base — different pinout and characteristics","has_detail_page":true}],"pins":[{"pin_number":"1","function":"Suppressor Grid (g3)","function_code":"g3","notes":null},{"pin_number":"2","function":"Cathode","function_code":"k","notes":null},{"pin_number":"3","function":"Suppressor Grid (g3)","function_code":"g3","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":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"7","function":"Anode","function_code":"a","notes":null},{"pin_number":"8","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"9","function":"Internal shield","function_code":"ia","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":"0.3","numeric_value":"0.3","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":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Vs_max","display_name":"Screen Voltage (max)","value":"250","numeric_value":"250","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"2.1","numeric_value":"2.1","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"0.55","numeric_value":"0.55","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"13","numeric_value":"13","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"150","numeric_value":"150","unit":"V","param_group":"absolute_max"},{"key":"Va","display_name":"Anode Voltage (typical)","value":"210","numeric_value":"210","unit":"V","param_group":"typical_operating"},{"key":"Vs","display_name":"Screen Voltage (typical)","value":"210","numeric_value":"210","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"10","numeric_value":"10","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"2.6","numeric_value":"2.6","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"550000","numeric_value":"550000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"7.1","numeric_value":"7.1","unit":"mA/V","param_group":"typical_operating"},{"key":"Rk","display_name":"Cathode Resistor (self-bias)","value":"220","numeric_value":"220","unit":"Ω","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.012","numeric_value":"0.012","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:42:06.403Z"}