About the vacuum tubes used by Consonance amps

Opera Audio has been manufacturing tube amplifiers for 14 years now. Throughout the 14 years the choice and application of tube has gradually become their own principal and style. Keen followers of Opera Audio will notice that, the power tubes used are mostly EL34, 6L6/KT66 and 300B. Although the tube brand names has changed from time to time but the type used are still the same. It is the sound delivered by the power tubes that becomes the first principle of Opera Audio's choice of vacuum tubes. EL34, 6L6/KT66 and 300B belongs to the high efficiency types with lively and detail sound, good transparency in high frequency. There is no need to say more of the 300B. The EL34 and 6L6/KT66 are famous due to their availability with different brand names, neutral sounding, good consistency and reliability. Therefore they are used by many manufacturers and consequently easier for users to enjoy tube rolling to suit their different taste. All in all this adds fun into the ownership of tube amplifiers.

The driver tube used by Opera Audio are largely 6SN7 (6N8P/6H8C) and Shuguang 6N8P is used in several models. The reason being there is a large stock of Shuguang 6N8P and comparing with import 6SN7 the quality is very close and it has very good reliability. The reliability factor is also the second principle of Opera Audio's choice of vacuum tubes. The use of Sovtek 6922 as pre-amplification is due to its smooth sounding characteristic with excellent transparency (also used by Audio Research and Sonic Frontiers). The tube used in Opera Audio's pre-amplifier like the T1 and QM-3 are US military JAN Philips 5814A (T99 uses Sovtek 6922) and this has a lot to do with circuit design. The pre-amplifier uses different improved SRPP circuit without global negative feedback but localized negative feedback, giving very good linearity and transient response. Opera Audio chooses 5814A (ECC82/12AU7) for its musicality and neutrality. 5814A are also more suitable for open loop circuit application.

In short, the sound of Opera Audio's tube amplifiers is neutral and natural with the driving stage as simple as possible. (The less driving stage the purer the sound and reduces the chance of colored sound). Whatever tubes that meets the above requirement will be considered, but ultimately the application will depend on power, internal impedance, and musical quality and circuit adaptation considerations.

In manufacturing application, all tubes are tested by Opera Audio's computer controlled vacuum tubes curve tracer, Sofia by Audiomatica of Italy.This effectively improves the quality of tube matching, reliability and life span of the tubes used by Opera Audio. On the other hand, except that model with self bias like the M500 and J500SE, all fixed bias tube amplifiers features power monitoring with adjustment capability. This enables the users to actively participate in the monitoring of the power tubes and this will extend the reliability of the power tubes. This is also the other major difference Opera Audio has in addition to the sound preference with other tube manufacturers. It is the same reason that all products sold will be back up by one-year standard warranty with 90 days warranty on vacuum tubes.