Standard commercial grade of the same frame-grid double triode — wider tolerances and shorter rated life than CCa/E88CC
PCC88
Series-string version with 7V heater — identical characteristics but different heater voltage, not a drop-in replacement
Electrical Specifications
Absolute Maximum
Anode Voltage (max)Anode Voltage (max)220V
Anode Dissipation (max)Anode Dissipation (max per section)1.5W
Cathode Current (max)Cathode Current (max per section)20mA
Heater-to-Cathode Voltage (max)Heater-to-Cathode Voltage (max)150V
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.
Pin Layout — Noval
1Anode (triode 2)
2Grid (triode 2)
3Cathode (triode 2)
Socket-Compatible Tubes ⚠ Not electrically compatible