About Opera Audio
"Simple, Human" our philosophy
Like other Hi-End audio manufacturers, Opera Audio specializes in the
development and research of tube audio amplifiers and CD-player. The
goal of realizing the beauty of music since the establishment of the
company 11 years ago has not been changed. "Simple, Human" refers
to revealing as much as possible the original spirit and artistic content
of music. To fill a static, cold machine with solid cultural content
and artistic energy, until the greatest visual and musical satisfaction
is reached.
About the vacuum tubes used by Consonance amps and CD-players
Opera Audio has been manufacturing tube amplifiers for 11 years now.
Throughout the 11 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 EL34/6550, 6L6/KT66 and
300B/2A3. 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. EL34/6550, 6L6/KT66 and 300B/2A3 belongs to the high
efficiency types with lively and detail sound, good transparency in high
frequency.
About single-ended amplifiers...
Single-ended class A amplifiers belongs to the elite family of tube amplifiers. Nowadays the famous Hi-End tube audio manufacturers like Jadis, Audio Note, Cary...etc all have their top model based on 300B single-ended amplifiers. The most famous vintage single-ended amplifier belongs to Western Electric's WE 91A, which was used for theatre and public PA application. They began in 1935 using a single 300B (early models were using 300A) with two 6C6 pentode and an input transformer to accept balanced input. Since the 300B has very good linearity, coupled with the simple class A single-ended circuit the harmonic distortion generated at the rated output is relatively small.
Single-ended class A amplifiers belongs to the elite family of tube amplifiers. Nowadays the famous Hi-End manufacturers like Jadis, Audio Note, Cary...etc all have their top model based on 300B single-ended amplifiers. The most famous vintage single-ended amplifier belongs to Western Electric's WE 91A, which was used for theatre and public PA application. They began in 1935 using a single 300B (early models were using 300A) with two 6C6 pentode and an input transformer to accept balanced input. Since the 300B has very good linearity, coupled with the simple class A single-ended circuit the harmonic distortion generated at the rated output is relatively small.
Usually at the maximum output the total harmonic distortion is less than 5% and they are mainly second harmonics. Matching with greater than 90dB speakers it generates rich musical sound and transparency. This is especially true when playing vocals and small chamber classical music. Before 1946 most theatre amplifiers made in the US were using triode as the power tube. Standard frequency response was 80Hz to 10KHz and the output power ranging from 10 to 16W. They were used for driving horn speakers. In the late 60s, the development of single end class A amplifier originated from Japan and since then the popularity of using it with high efficiency speakers increased.
The tube used were mainly directly heated triode 300B, 2A3 and 845. Among them 300B has the best sound. This quickly spread to Europe and then the whole world with this type of amplifier being regarded as an all time classic. The top models in Opera Audio's amplifier line up like the M500, M500S, J500SE and J400 are all based on the 300B single-ended class A design. Nowadays single-ended class A amplifiers are everywhere. Not only the speaker sensitivity can now be made easily greater than 90dB and the improvement of components quality, the most important reason is the incredible sound reproduction.
Single-ended amplifier's circuit is very simple. For a power amplifier usually there is a voltage amplification stage, driver stage and power amplification stage. The use of only one driver tube and one power tube in a single-ended amplifier (like the M500) is even more simple. The change in sound is almost due entirely to the power tube and the output transformer. Single-ended amplifier can also use two power tubes in parallel to increase the output power (like the M500S and J400). In that case the output power is doubled and the output impedance is reduced by half. The driving voltage is the same but the distortion is a bit bigger than using only one power tube. Up to a certain degree, better linearity of the power tube and high quality of the output transformer has the most important effect on the sound of single-ended amplifiers. Due to the output transformer of single-ended amplifiers always has a large amount of DC flowing through, in order to avoid distortion caused by magnetic saturation of the iron core, there should be air gap in the iron core. To obtain a good low frequency response, the size of the iron core also needed to be increased. Usually the size of a well designed output transformer of a single end amplifier is physically 3 to 4 times bigger than a similar output transformer designed for push pull..
Due to this reason, the cost of single end output transformer is therefore more expensive. The single-ended output transformer used by Opera Audio are using high grade silicon steel and reasonable design to enable good low frequency response. At the same time optimized for high frequency distortion and sound characteristic. Special fixation frame is used and the whole assembly is dipped into special wax to maintain a constant air gap which is vital for a good output transformer.
