{"type_number":"EF6","canonical_url":"https://tubeofile.com/tubes/EF6","manufacturer":"Philips","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"P8A","description":"Sharp-cutoff RF/AF pentode on European side-contact base (P8A) with top-cap anode. Introduced by Philips in the 1938 Miniwatt range. Used as a voltage amplifier in radio receivers and audio equipment. Superseded by Noval types (EF40, EF80) in post-war designs.","is_directly_heated":false,"completeness":"high","notes":["European side-contact base P8A (also designated Au P or 8SC) with top-cap anode connection.","Part of the Philips 1938 Miniwatt all-glass tube range using the P8A pressed-glass base construction.","Brans Vademecum lists EF6 in the same functional family as 6SJ7, EF36, EF37A, EF40, EF80, and E80F — but these are NOT pin-for-pin equivalents due to different base types.","TDSL lists 6E2, S620, TEF6, and VEF6 as close or identical substitutes.","The EF6 shares the P8A base family with other Philips tubes like EF50, EL50, and EF9 — check pin assignments before interchanging.","Muiderkring data categorises EF6 as pentode (category 'p').","Philips interchange guide (1962) lists EF6 with no recommended replacement — indicating it was considered unique in its base type."],"references":["https://tdsl.duncanamps.com/show.php?des=EF6"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EF6","radiomuseum":"https://www.radiomuseum.org/tubes/tube_ef6.html"},"raw_equivalents":["6E2","S620","TEF6","VEF6"],"equivalents":[],"similar":[{"type_number":"6SJ7","reason":"American Octal equivalent by function (sharp-cutoff pentode) — similar electricals but Octal base","has_detail_page":true},{"type_number":"EF36","reason":"Electrically equivalent pentode but Octal base — not pin-compatible with P8A side-contact base","has_detail_page":true},{"type_number":"EF37A","reason":"Improved version of EF36 on Octal base with lower microphony — same electrical characteristics, different base","has_detail_page":true},{"type_number":"EF40","reason":"Post-war Rimlock (B8A) replacement with similar characteristics — different base type","has_detail_page":false},{"type_number":"EF6N","reason":"Variant designation for the same tube — verify exact manufacturer/version before substituting","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Metallization / Screen","function_code":"ia","notes":null},{"pin_number":"2","function":"Heater","function_code":"h","notes":null},{"pin_number":"3","function":"Cathode","function_code":"k","notes":null},{"pin_number":"4","function":"Suppressor Grid (g3)","function_code":"g3","notes":null},{"pin_number":"5","function":"Control Grid (g1)","function_code":"g1","notes":null},{"pin_number":"6","function":"Screen Grid (g2)","function_code":"g2","notes":null},{"pin_number":"7","function":"Heater","function_code":"h","notes":null},{"pin_number":"TC","function":"Anode (top cap)","function_code":"a","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":"150","numeric_value":"150","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"1.5","numeric_value":"1.5","unit":"W","param_group":"absolute_max"},{"key":"Ps_max","display_name":"Screen Dissipation (max)","value":"0.3","numeric_value":"0.3","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":"Rg_max","display_name":"Max Grid Resistor","value":"1","numeric_value":"1","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":"100","numeric_value":"100","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","numeric_value":"3","unit":"mA","param_group":"typical_operating"},{"key":"mAs","display_name":"Screen Current","value":"0.8","numeric_value":"0.8","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"1000000","numeric_value":"1000000","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"2.2","numeric_value":"2.2","unit":"mA/V","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"0.005","numeric_value":"0.005","unit":"pF","param_group":"capacitances"},{"key":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"7","numeric_value":"7","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"5","numeric_value":"5","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:41:16.681Z"}