Product Review - Opera
Reference R1.1 Tube Preamplifier - June, 2002
David Wurtz - Editor, AUSTRALIA
3 Hz - 150
kHz (-1 dB) (35 Pounds)
The Opera Audio Co, Ltd., No.4 Xihai Xiyan, Xichen District, Beijing, China, 100035; Tel: 10-62220935 FAX: 10-62220935 ; E-Mail: email@example.com; Web http://www.operaudio.com.cn/company/operaudio/eindex/eindex.htm
Late last year I introduced Secrets readers to the Chinese built Opera Audio M400 tube mono blocks. I was very impressed with the sound quality and especially the price of these units. Opera Audio also produce a “reference range”. These are obviously more expensive than their standard product range, but is there a reference quality sound from them? Let's see.
Externally the most obvious feature is the cherry wood timber top. It is curved to marry the design of the machined aluminum fascia and also acts as a vibration damper for the electronics. The aluminum fascia reminds me of the 1970's Panasonic range of Hi-Fi components. While I quite like the cherry wood top, I am not as fussed with the fascia. Four large silver knobs adorn the fascia plate and from left to right are: “Power“ – “Function” (3 inputs) – “Volume” – and the -10 dB mute switch.
The Power, Function, and Mute knobs are standard type switches and feel quite solid when turning them. The most interesting is definitely the volume control. Instead of using a sweeping potentiometer, it use a single stereo ELMA - 24 position series attenuator with 46 Holco 1% precision resistors attached (see photo on left, below). This is commonly referred to as a stepped potentiometer. Essentially, it means that the volume is supplied in 24 steps with a solid click at each step. This is very expensive to produce, and I feel is one of the main features of this unit. In use, it was somewhat difficult to obtain an exact desired listening level, but I got used to it. The –10 dB mute switch is meant to be used in conjunction with the volume control to extend the life of the expensive switch assembly. I must admit that I notice a slight decease in sound quality when the switch was activated, but its function is to turn down the level when you answer the phone or whatever, without using the volume control knob. On the back, the Reference 1.1 has three pairs of high quality gold plated input RCA jacks and two pairs of output RCA jacks.
The bottom reveals three feet in a dome shape made from plated brass. This idea of only three feet is now being used by other amplifier manufacturers, i.e., the Audio Aero “Capitole” tube amp uses the same configuration (one at the front in the middle and two at the back on either side). The idea is that with three feet, there will always be absolute contact with the support shelf, like a tripod.
Internally, capacitors used for signal coupling are the US MultiCap RTX, and Rel-Cap were also noted. A combination of the high quality Holco and some Chinese made Precision Aerospace (the low temperature drift version) resistors are used throughout.
A special silicon steel EI type power transformer and choke with good high frequency response (electro-magnetically shielded from the circuit board) are used together with large Solen MKP metallized polypropylene capacitors and one electrolytic for power supply filtering.
The two valves (tubes) used in the main circuit are the well renowned 12AU7. The particular type supplied were NOS (New Old Stock) manufactured in the 50/60s. Due to limited supply they are quite expensive but absolutely one of the very best. To reduce the microphone effect, two pearl tube coolers are used. These also act as a very good heat sink, which can greatly extend tube life. 12AU7s are dual triodes, with similarities to other such designs as the 12AT7 and 12AX7, used in preamplifiers. Triodes are valued for their characteristic even-order distortion, rather than odd-order distortion found in solid state devices. They are usually run in pure Class A.
Interestingly, the components are mounted on a circuit board but are hand wired (no printed circuit traces) with internal hook-up wire from VDH. This serves a dual purpose of having a neat layout (components mounted on a circuit board) while still using high quality hand wiring. Remember, some purists insist on having no printed circuit boards carrying the signal. That is the case here.
Essentially the manufacturer has designed this component to have no acoustic signature other than the sound of the valves. So, if you like the sound of a particular tube, the Reference R1.1 is theoretically able to reproduce its sound verbatim, which as I said, in theory a very nice feature. During the evaluation period I was unable to replace the tubes with differing brands to prove this, but changing tubes to reflect personal preferences is common in the tube world.
Using my Redgum DVD player's digital output into a Perpetual Technologies P1A and P3A combo, then into the Consonance Reference R1.1, followed by an ME 550 power amplifier and Osborn Epitome Reference loudspeakers, I commenced the evaluation.
I allowed about 100 hours “burn-in”. There was a noticeable improvement in sound quality in the first 70 hours, at about 100 hours the improvements were minimal. Note that there are arguments for and against the true nature of burn-in. Is there really a change, or do we just get used to whatever the sound quality is there and it does not really change? Subject for a different day.
I must say up-front that this is a wonderful sounding product. No other preamp I have added to my system has sounded this good. Notably the R1.1 broadened the soundstage, increased my system's resolution, but in doing this, did not really add any sonic signature. The sound was silky smooth with a sweet top end, powerful, yet well articulated midrange, well rounded low-mids, and had deep tight bass.
Cymbals retained their tonal characteristics, rich in overtones and precise in their position in the soundstage. Orchestral music was very well presented, individual instruments, violins, piano superbly accurate, and tonally perfect.
Beethoven's 5th is one of my favorite classical compositions, and the version I have performed with the London Philharmonic is always a head turner when played through a high-end system. The piano in this recording was treated with the utmost care and precision. Each strike of the hammer onto the string could be felt, the decay, elegant and natural. The added orchestra filled the room with beautiful sounding instruments. This was a very satisfying experience!
Shane Howard's solo album "River" has some excellent spacious recordings. The R1.1 gave me an almost completely transparent soundstage with exceptional width, depth, and height. The smooth tube sound was a perfect match for the ambience created. A nice feature of the Consonance is that it is extremely dynamic when required. I have noticed that other valve preamps can lag behind a little or become mushy when a lot of high level information is being fed into them. Not the R1.1 though. I heard the warm rounded valve sound with the speed and precision of high end transistor types. More aggressive rock albums from the likes of the "Stone Temple Pilots" and "Powderfinger" where handled with ease, with the R1.1 not holding back on releasing the energy from powerful snare and bass drums and crunching guitar riffs.
With a wonderfully neutral and non-colored sound, while increasing resolution, the Consonance Reference R1.1 is exactly that in my opinion, a reference. To be honest, I am very very impressed with the designers at Opera Audio. The Chinese (particularly Opera Audio) are producing some wonderful tube products for what is in their grand scheme of things, not a lot of money. For the $4300AUS, what this product does to increase resolution is worth that amount alone. The fascia is not to my exact taste, but I absolutely love the sound, and lets face it, “das wot ‘tis all ‘bout”. This unit is a fine addition to any system, and so, is Highly Recommended!
- David Wurtz -
© Copyright 2002 Secrets of Home Theater & High Fidelity
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