{"type_number":"12BH7","canonical_url":"https://tubeofile.com/tubes/12BH7","manufacturer":null,"tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Noval","description":"Double triode, medium-mu, semi-high perveance, miniature 9-pin type. Originally designed for use as a combined vertical deflection sweep generator and deflection amplifier in television receivers, now widely used as an audio driver and line-stage tube.","is_directly_heated":false,"completeness":"high","notes":["Heater has a center tap (pin 9) allowing operation at either 12.6V/0.3A (series) or 6.3V/0.6A (parallel). For 12.6V operation, apply heater voltage between pins 4 and 5. For 6.3V operation, apply heater voltage between pin 9 and pins 4+5 connected together.","Pin-compatible with the ECC81/ECC82/ECC83 family (same B9A twin triode pinout) but NOT electrically interchangeable — the 12BH7 draws significantly more heater current (0.6A vs 0.3A at 6.3V) and has much higher plate dissipation (3.5W vs 1.0-1.2W per section).","Maximum grid circuit resistance differs significantly between self-bias (2.5 MOhm) and fixed-bias (1 MOhm for Class A1, 0.25 MOhm for vertical deflection). Use caution with fixed-bias designs.","The Tung-Sol datasheet (1950) lists two operating points: a low-voltage point at Va=85V with mu=21 and gm=6200 umho, and the standard 250V point. The higher mu at low voltages makes it attractive for low-voltage audio designs.","The 12BH7A is an improved version with tighter specifications but identical pinout and ratings."],"references":["https://frank.pocnet.net/sheets/127/1/12BH7.pdf","https://frank.pocnet.net/sheets/084/1/12BH7.pdf"],"source_urls":{"r_type":"http://www.r-type.org/exhib/aaa0177.htm","tdsl":"https://tdsl.duncanamps.com/show.php?des=12BH7","radiomuseum":"https://www.radiomuseum.org/tubes/tube_12bh7.html"},"raw_equivalents":["12BH7A","CV5042","13D6","6913","7032"],"equivalents":[],"similar":[{"type_number":"6BL7GT","reason":"Similar medium-mu twin triode but Octal base vs Noval for 12BH7","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Anode (Section 2)","function_code":"a2","notes":null},{"pin_number":"2","function":"Control Grid (Section 2)","function_code":"g1_2","notes":null},{"pin_number":"3","function":"Cathode (Section 2)","function_code":"k2","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 (Section 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Control Grid (Section 1)","function_code":"g1_1","notes":null},{"pin_number":"8","function":"Cathode (Section 1)","function_code":"k1","notes":null},{"pin_number":"9","function":"Heater Center Tap","function_code":"h","notes":null}],"specs":[{"key":"Vh","display_name":"Heater Voltage","value":"12.6 / 6.3","numeric_value":"12.6","unit":"V","param_group":"heater"},{"key":"Ah","display_name":"Heater Current","value":"0.3 / 0.6","numeric_value":"0.3","unit":"A","param_group":"heater"}],"sections":[{"section_number":1,"section_label":"Triode","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"300","numeric_value":"300","unit":"V","param_group":"absolute_max"},{"key":"Pa_max","display_name":"Anode Dissipation (max)","value":"3.5","numeric_value":"3.5","unit":"W","param_group":"absolute_max"},{"key":"Ik_max","display_name":"Cathode Current (max)","value":"20","numeric_value":"20","unit":"mA","param_group":"absolute_max"},{"key":"Vhk_max","display_name":"Heater-to-Cathode Voltage (max)","value":"180","numeric_value":"180","unit":"V","param_group":"absolute_max"},{"key":"Rg_max","display_name":"Max Grid Resistor","value":"2.5","numeric_value":"2.5","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":"-10.5","numeric_value":"-10.5","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"11.5","numeric_value":"11.5","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"5300","numeric_value":"5300","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"3.1","numeric_value":"3.1","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"16.5","numeric_value":"16.5","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"2.4","numeric_value":"2.4","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"3","numeric_value":"3","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"0.8","numeric_value":"0.8","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T12:04:41.326Z"}