Consonance Reference 9.9 Power Amplifier
There is a saying about beautiful women. The
most ideal being beautiful both inside and out. If she is
beautiful on the inside but without the looks, then it is
still regret. This is the case with the tube amplifiers
made by Opera Audio. They are known for producing beautiful
music but not the looks. However the new Reference 9.9 power
amplifier with the matching Reference 1.1 preamplifier is
a breakthrough for Opera Audio. Not only it has refreshing
new outlook; the sound also has a unique character of its
own. I can say this reference series has revolutionary changes
both inside and out.
Once the "reference" word is mentioned,
audiophiles alike are paying special attention. It is because
audiophiles seek after most amplifiers bearing this word.
Matisse, Audio Research and Sonic Frontiers all has reference
series products that are very famous. The fact is reference
level equipment are highly rated and respected by the Hi-End
market. Now Opera Audio also produces reference 845 mono-block
power amplifier to compete with the US and European makes.
Is this a real challenge or hoax? Let us check it out.
This R9.9 review is not following the usual
pattern of talking about outlook, design and then sound.
I really have to talk about the R9.9 outlook. Comparing
with the other products of Opera Audio that follows the
traditional path, the R9.9 is a complete breakthrough with
the outlook that gives a tremendous feel of quality. Consonance's
line of tube amplifiers is famous for delivering good sound
and is well respected in China market solely due to the
quality of the sound. The outlook according to the "simple,
human" philosophy is a bit disappointing (at least
to me). However R9.9 is a milestone for Opera Audio. Since
then Opera Audio's tube amplifiers will not be judged only
by their sound.
Tube amplifier design can be the box or open
type. Box type looks tidier but the open type has more audiophile
feeling. For audiophiles who like tube rolling they prefer
the open type that looks more elegant and warm. However
they are also very difficult to look tidy as well, especially
you have to take into consideration the relatively big transformers
and power supply filtering components. However the R9.9
design is quite innovative due to its "half" box
type design. The front half facing the front panel is box
type housing the transformers, choke and electrolytic capacitors.
These are covered with the top cover using cherry wood as
decoration. It has a quality feel. The bottom half is open
type with an 845 power tube, an E88CC and 5687 small vacuum
tube. The height of the 845 tube is higher than the chassis
cover surrounded by plated metal rods. The front panel is
made of aluminum with a curved top edge and the power on/off
push button is at the lower middle position. Above the power
switch there is a small black metal opening housing the
"cats' eye". This is another new design. Inside
the "cats' eye" is a 6E2 vacuum tube. It is used
in the vintage type radio receiver. The amount of closing
of its green display indicates the current output power.
This is a nostalgic, human and warm design better than using
a conventional VU meter.
The size of R9.9 is not small but also not
too bulky. It looks classic and elegant with a bit of modern
glamour. This is a result of numerous fine-tuning the proposal
from The Beijing Institute of Arts. In my opinion, this
design should be patented.
Although the manufacturer does not want to
publish the circuit diagram, I would still like to talk
about it. R9.9 uses one 845 in each channel for single end
amplification. The front end is using an E88CC in common
cathode voltage amplification. Another 5687 is used as driver.
The driving stage is key in R9.9. The use of 845 in class
A single end amplification is to make use of its warm and
"thick" character of a directly heated triode
as well as large output power. The 845's plate voltage is
more than 1000V and the grid voltage is more than -100V.
Due to this, the voltage swing during operation is quite
large in order to obtain enough margin for linear operation.
This presents a difficult task for the driver, as it needs
to have enough capability to satisfy and adapt to the operation
characteristic of 845. Due to this, the 845 amplifiers made
in China are using different means in implementing their
driver stage. The most common method is the use of inter-stage
transformer to increase the voltage swing. There are also
others using EL34, 6P3P and 300B as driver but they face
other problems. The use of EL34 or 6P3P as driver will bring
their pentode and tetrode tube sound into the 845 and polluting
the tumbrel balance of the directly heated triode. The use
of the expensive 300B to drive 845 will increase the cost
of the amplifier. On the other hand, the 300B driver circuit
is complex and will color the sound of the 845. When implemented
poorly it will degrade and dominate the output sound. You
lose more than you gain. As a result, when designing 845
amplifier the driver stage is very important.
R9.9's driver stage does not have inter-stage
transformer and power tube but uses a single high mu 5687
dual triode. Although 5687's mu is higher than other dual
triodes, its plate voltage and filament voltage is far from
meeting the 845 requirement. How can it survive the macro-dynamics?
R9.9 is using relatively mild plate voltage of 1000V, not
higher to achieve the necessary gain. Hence with this configuration
how can the R9.9 achieve the output power of 28W? The mystery
lies with the use of 5687 in.... The mystery lies with its
In addition, R9.9 uses three transformers,
a filtering choke and 6 220uF Rubycon electrolytic capacitors
in each channel. Among the three transformers, one is for
high tension and front stage, one is the output transformer
and the smaller one is for the 845 filament supply. 845
is directly heated and its filament is the cathode. Using
a separate filament supply will reduce the inter-modulation
distortion due to stability of the filament voltage under
all circumstances. Furthermore, the front stage vacuum tubes
are carefully selected. E88CC is the gold pins Siemens made
in Germany. 5687 is the US GE NOS. Internal circuit is very
simple with few components. However premium components like
Rel-Cap coupling capacitors can still be seen.
The initial impression after hearing the R9.9
can be described as follows; if you do not know what it
means by "tube" sound, please hear the R9.9. This
is the richest "tube" sounding amplifier that
I have ever listened to. Warm, full of body, sweet, transparent,
airy, detail and rich in harmonics; any description you
have for "tube" sound are here. No matter what
kind of music you play, from violin solo, symphonies to
piano, it elevates you to a higher state. In the past whenever
I listen to a tube amplifier, I always have the thought
that a good quality solid state amplifier can achieve the
same sound. But here the sound is warm, full of body, lively,
delicate and dynamic makes you forget about solid state
amplifier forever due to its harshness in comparison.
Does it mean coloration then? It should be
yes but you cannot conclude this coloration as a result
of distortion. The coloration of R9.9 is the kind founded
on the faithful reproduction of the original. It is like
the Amsterdam Philharmonic Orchestra has their unique Amsterdam
timbre to it. If you go attend their live performance, you
will notice that they have their own characteristic sound
that is warm and sweet. Can you then say their performance
Since the new products have received more
than expected orders, Opera Audio does not have any spare
R9.9 on loan for review. Hence this review took place in
their auditioning room. The review combination uses their
R1.1 preamplifier, Harbeth HL Compact 7 speaker. Source
is Philips 951 as transport with Parasound as D/A. I have
been using the same speaker for 5 years and am very familiar
with it. I drove it with numerous amplifiers but none of
them gave the sound like R9.9. The rich middle frequency
of HL7 has authority and the low frequency goes very deep.
This is not the same HL7 that I am familiar with. While
giving R9.9 an evaluation, the HL7 should also be given
a new evaluation.
The sound of R9.9 is laid back but not soft,
full of body but not over done, delicate but does not lack
authority. Once you hear it you have the immediate feeling
that this comes from a high end amplifier. R9.9 has both
the warm, full body and transparent character of a directly
heated triode, and the strength and authority of a high
power pentode. The violin sound reproduced is no less beautiful
than a good 300B single end amplifier. With symphonies it
displays its special style, such as rich hall sound, wide
soundstage and clear imaging. It is like the band is playing
right there at ease. It handles peak dynamics well. Not
in an aggressive way but extends to the extremes. The bass
is tuneful with weight and goes deep. R9.9 has very good
vocal imaging. While playing Cai Qin's old songs CD her
vocal imaging is clear with each and every minor details
revealed. What is touching is the revealing of the inner
content and feelings of music. This is exactly what distinguishes
between an art and a machine, an artist and a craftsman.
The rich musical performance and artistic influence is clearly
the model for great high fidelity equipment.
The resolution of R9.9 belongs to above average
but not the best comparing with high quality solid state
amplifier. However for tube amplifier it is like that. Resolution
is like cameras. If high quality solid state amplifier is
comparable to Nikon, then R9.9 is equal to Canon.
The sound of R9.9 is on the warm side. The
overall feeling is intimate, rich, solid and dynamic. You
can never play R9.9 to thundering sound pressure level but
you should not look down upon it. Its middle and low frequency
has authority, density and weight. R9.9 takes a firm position
in revealing the inner dynamics of music. There is no doubt
R9.9 can live up to be the reference level power amplifier
of Opera Audio and among Chinese tube amplifiers.
Personally I prefer large pieces of hi-fi
equipment since they can reproduce delicate music as well.
The reason of me using Krell amplifier is due to its power
and versatility. After hearing the R9.9 I am a bit moved.
If R9.9 can drive ATC speaker then it will be amazing. How
much driving power R9.9 has is not known and I do not have
the opportunity of testing the R9.9 driving Spendor SP100
or ATC. Theoretically it is possible but using one pair
of 845 is kind of tough. If only I can try using two pairs
in bi-amp configuration it will be interesting. The imported
high power tube amplifiers are very expensive and I cannot
afford them. Jadis JA500 is very good but replacing the
power tubes for both channels involves 24 pieces of 6550.
This alone is scary. R9.9 is more than 10 thousand RMB per
pair. For two pairs it is about the same price as Krell
300i. For users of either bookshelf or larger speakers they
should give the Reference 9.9 an audition.
High Fidelity 2001 issue 1, China