{"type_number":"CCa","canonical_url":"https://tubeofile.com/tubes/CCa","manufacturer":"Siemens","tube_type_key":"small_signal_triode","tube_type_display_name":"Small Signal Triode","base_name":"Noval","description":"Siemens & Halske premium-grade double triode with frame-grid construction. Factory-selected E88CC with tighter tolerances, lower noise, and longer rated life. Developed for long-distance telephony (Weitverkehr) and professional instrumentation. Electrically identical to E88CC/6922 but with stricter parameter matching.","is_directly_heated":false,"completeness":"high","notes":["CCa is NOT an ECC83/12AX7 equivalent. It is the Siemens premium-grade designation for the E88CC/6922 frame-grid double triode family.","Originally developed for Siemens long-distance telephony equipment (Weitverkehrsröhre / Poströhre) where low noise and long life were critical.","TDSL lists CCa as 'close or identical' to 6922, 6922WA, E88CC, CV2492, CV2493, CV8065, E88CC01, ECC868. Lists ECC88, 6DJ8, 6N23P as 'different rating or performance'.","This is a low-voltage tube — typical operation at Va = 90 V, much lower than conventional dual triodes like 12AX7 (Va = 250 V).","Max Pa is 1.5 W per section (E88CC spec). Fixed grid bias is only permitted when Ia <= 5 mA.","Pin 9 is an internal shield between the two triode sections.","Philips interchange guide (1962) maps CCa to E88CC;6922."],"references":["https://tdsl.duncanamps.com/show.php?des=CCa","https://frank.pocnet.net/sheets/049/6/6922.pdf"],"source_urls":{"r_type":null,"tdsl":"https://tdsl.duncanamps.com/show.php?des=CCa","radiomuseum":"https://www.radiomuseum.org/tubes/tube_cca.html"},"raw_equivalents":["E88CC","6922","6922WA","CV2492","CV2493","CV8065","CV10320","E88CC01","ECC868","6DJ8","ECC88"],"equivalents":[{"type_number":"6922","equivalence_type":"direct","notes":null},{"type_number":"6DJ8","equivalence_type":"direct","notes":null},{"type_number":"ECC88","equivalence_type":"direct","notes":null}],"similar":[{"type_number":"E188CC","reason":"Even higher reliability grade (7308) — can substitute for CCa but not vice versa in critical applications","has_detail_page":false},{"type_number":"PCC88","reason":"Series-string version with 7V heater — identical characteristics but different heater voltage, not a drop-in replacement","has_detail_page":false}],"pins":[{"pin_number":"1","function":"Anode (triode 2)","function_code":"a2","notes":null},{"pin_number":"2","function":"Grid (triode 2)","function_code":"g1_2","notes":null},{"pin_number":"3","function":"Cathode (triode 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 (triode 1)","function_code":"a1","notes":null},{"pin_number":"7","function":"Grid (triode 1)","function_code":"g1_1","notes":null},{"pin_number":"8","function":"Cathode (triode 1)","function_code":"k1","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":"Triode","tube_type_key":"small_signal_triode","specs":[{"key":"Va_max","display_name":"Anode Voltage (max)","value":"220","numeric_value":"220","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":"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":"150","numeric_value":"150","unit":"V","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":"90","numeric_value":"90","unit":"V","param_group":"typical_operating"},{"key":"Vg","display_name":"Grid 1 Bias Voltage","value":"-1.2","numeric_value":"-1.2","unit":"V","param_group":"typical_operating"},{"key":"mAa","display_name":"Anode Current","value":"15","numeric_value":"15","unit":"mA","param_group":"typical_operating"},{"key":"ra","display_name":"Anode Resistance","value":"2650","numeric_value":"2650","unit":"Ω","param_group":"typical_operating"},{"key":"gm","display_name":"Transconductance","value":"12.5","numeric_value":"12.5","unit":"mA/V","param_group":"typical_operating"},{"key":"mu","display_name":"Amplification Factor (μ)","value":"33","numeric_value":"33","unit":"—","param_group":"typical_operating"},{"key":"Cgp","display_name":"Grid-to-Plate Capacitance","value":"1.4","numeric_value":"1.4","unit":"pF","param_group":"capacitances"},{"key":"Cin","display_name":"Input Capacitance","value":"3.3","numeric_value":"3.3","unit":"pF","param_group":"capacitances"},{"key":"Cout","display_name":"Output Capacitance","value":"0.18","numeric_value":"0.18","unit":"pF","param_group":"capacitances"}]}],"synced_at":"2026-04-07T19:06:24.027Z"}