While going through a recently acquired pile of tubes, I discovered the Raytheon 9au7 short black plates, a 9v version of the 12au7 that, interestingly, shares the same pinout as the 6DJ8 or 6CG7. Although this particular unit was branded as RCA, the flat short black plates revealed its true Raytheon origin, it performed exceptionally well even in a 6v circuit despite the 9v heater requirement.
I absolutely could not believe the sound quality, it is easily the most musical and liquid tube I have ever experienced. The vocal reproduction is stunning, allowing every singer to open up their soul, while the bass remains very strong and tight with delicious detail throughout. In a blind test against a Siemens E88CC, this incredible $3 find actually beat out the $100 heavyweight in vocal performance. It is a mystery how such a gem has escaped wider attention, likely due to its rare and unusual heater voltage, making it a true sleeper hit.
Final Verdict: Highly Recommended for any system that can utilize 6CG7, 6DJ8, or 6AQ8 tubes, you might be very pleasantly surprised.
While going through a recently acquired pile of tubes, I discovered the Raytheon 9au7 short black plates, a 9v version of the 12au7 that, interestingly, shares the same pinout as the 6DJ8 or 6CG7. Although this particular unit was branded as RCA, the flat short black plates revealed its true Raytheon origin, it performed exceptionally well even in a 6v circuit despite the 9v heater requirement.
I absolutely could not believe the sound quality, it is easily the most musical and liquid tube I have ever experienced. The vocal reproduction is stunning, allowing every singer to open up their soul, while the bass remains very strong and tight with delicious detail throughout. In a blind test against a Siemens E88CC, this incredible $3 find actually beat out the $100 heavyweight in vocal performance. It is a mystery how such a gem has escaped wider attention, likely due to its rare and unusual heater voltage, making it a true sleeper hit.
Final Verdict: Highly Recommended for any system that can utilize 6CG7, 6DJ8, or 6AQ8 tubes, you might be very pleasantly surprised.