{"type_number":"EF806S","canonical_url":"https://tubeofile.com/tubes/EF806S","manufacturer":"Telefunken","tube_type_key":"ss_pentode","tube_type_display_name":"Small Signal Pentode","base_name":"Noval","description":"Special quality (SQ) low-noise AF pentode for high-gain audio pre-amplifiers. Electrically identical to EF86 with tighter tolerances, improved vibration/shock resistance (2.5 g at 50 Hz, 500 g momentary), and guaranteed 10,000 hour life.","is_directly_heated":false,"completeness":"high","notes":["Electrically identical to EF86 but with tighter parameter tolerances and superior mechanical construction (vibration/shock resistance).","Pins 2 and 7 are internal metallic shields for hum and noise reduction — must be grounded for lowest noise.","Pin 8 (g3/suppressor) is internally connected to cathode.","Equivalent noise voltage: approx. 2 µV (25–10,000 Hz bandwidth) at Vb = 250 V, Ra = 100 kΩ (CCIF-Norm 1949).","Vhk_max = 100 V (cathode positive of heater only). Maximum bulb temperature: 170 °C.","Rg_max depends on anode dissipation: 10 MΩ for Wa < 0.2 W, 3 MΩ for Wa > 0.2 W, 22 MΩ if bias is from Rg1 drop only.","5879 / CV4086 are functional substitutes but use a B7G (7-pin miniature) base — not pin-compatible.","Triode connection operating data documented on Telefunken datasheet pages 2–3 with three RC-coupled amplifier configurations (Ra = 47 kΩ, 100 kΩ, 220 kΩ) at supply voltages 200–400 V. Small-signal triode characteristics (μ, gm, ra) from Tom Schlangen measurements, consistent with datasheet stage-gain data."],"references":["https://frank.pocnet.net/sheets/128/e/EF806S.pdf","https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ef806s.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=EF806S","radiomuseum":"https://www.radiomuseum.org/tubes/tube_ef806s.html"},"raw_equivalents":["6267","Z729","M8195","CV4085","6CF8","EF86","EF804S","6J32P"],"equivalents":[{"type_number":"6J32P","equivalence_type":"direct","notes":null},{"type_number":"EF86","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"5879","reason":"Functional substitute but B7G (7-pin) base — not Noval","has_detail_page":true},{"type_number":"CV4086","reason":"Functional substitute but B7G (7-pin) base — not Noval","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":"-2.2","numeric_value":"-2.2","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":"2.2","numeric_value":"2.2","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":"Cgk","display_name":"Grid-to-Cathode Capacitance","value":"4.0","numeric_value":"4","unit":"pF","param_group":"capacitances"},{"key":"Cak","display_name":"Anode-to-Cathode Capacitance","value":"5.5","numeric_value":"5.5","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":"µg2g1","value":"38","numeric_value":"38","unit":null,"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":"2026-04-07T19:07:54.822Z"}