The R1.1 Reference Preamplifier

"This Preamp is a real giant killer. A completely no compromise design"

                                       
                                                   
Click for Hi Res Photograph


The R1.1 represents the top model of Opera Audio's current range of per-amplifiers. It is a 20dB gain line stage pre-amplifier using improved SRPP circuit with no global negative feedback. The equipment top uses cherry wood while equipment feet are brass cones for improved shock absorption. Front plate is of machined aluminum.The internal components used are among the finest available in the world today. The potentiometer uses the single stereo ELMA 24 position series attenuator with 46 Holco 1% precision resistors. Apart from having excellent sonic characteristic, it guarantees the sound stage precision at any volume level. The capacitors used for signal coupling is both the exotic US MultiCap RTX and the Rel-Cap. Resistors used is a combination of Holco and Chinese made precision aerospace low temperature drift version. All connections are point to point wiring using Kimber high purity copper hook up wire. The circuit board acts as a support frame for the tubes and other components and actual point to point wirings are done beneath the circuit board.

The two tubes used in the main circuit is the fabulous sounding French RT12AU7 NOS made in the 50/60s. Due to limited supply they are very hard to find in the market and price-wise expensive but absolutely one of the very best. In order that users can try out different types of 12AU7, the R1.1 is designed to use components that has very little colored sound of their own. In this way, during tube rolling the R1.1 can clearly show off the sound of the tube itself. A lot of satisfaction will then be achieved by trying out other exotic tubes like the Telefunken and Mullard.
Good quality pre-amplifier calls for a good quality power supply. The power transformer and choke is shielded from the circuit board. A special silicon steel EI type power transformer and choke with good high frequency response is used together with large Solen MKP metallized polypropylene filtering capacitor. Its filtering characteristic is very uniform across the frequency range and adds to the purity of the sound.

To reduce the microphone effect, two Pearl tube coolers are used. Not only they are effective in reducing microphone effect, they are also a very good heat sink which can greatly extend tube life. Other convenient features are added like the -10dB muting switch, which can reduce the usage of the expensive potentiometer and as a result extends its life.

 Features:

 1.
Special made EI power transformer and choke covered by a copperized cover.

 2.
All substantial filter/reservoir capacitors are SOLEN(100U/400V 1pcs, 68U/400V 1pcs).

 3.
ELMA precision stepped Volume control (unbalance<0.5% per channel).

 4.
High quality parts such as MIT capacitors,HOCOL resistors which are skillfully hand wired under the chassis,using WBT solder.

 5.
Every tube uses a tube-damper for zero microphony performance.

 6.
Cherry-wood made camber for top chassis and brushed aluminium front panel with natural color.


 Specifications:
 FREQUENCY RESPONSE: 3Hz to 150kHz ( -1dB)
 GAIN at 1kHz: 21.8dB
 HARMONIC DISTORTION (for 2V RMS at output): 0.08%(70Hz/7kHz 4:1)
 SIGNAL/NOISE: 90dB
 INPUT INTERFACES: 3 groups (RCA)
 OUTPUT INTERFACES: 2 groups (RCA)
 INPUT IMPEDANCE: 100k
 CONSUMPTION: 40W
 VACUUM TUBE: 12AU7(NOS) x2
 DIMENSIONS: 430(L) x 320(W) x 120(H) mm
 WEIGHT: 16kg

This preamp makes it hard to believe that something this exceptional could be so cheap. Virtually everyone who has auditioned it has bought one because of the miraculous things it does to their system. Customers with preamps by respected names such as Mark Levinson, Krell, Morrison, Audio Research and many other solid state and tube designs have marvelled at the detail, timber and soundstage width and depths which it portrays. My previous pre cost several times the price of the R1.1 but sounded dull and lifeless in comparison. I sometimes wish it had a remote volume, which can be ordered, but with a considerable loss of detail as the stepped volume control is a work of art. (see photo.on left)  Even David Wurtz, the Australian Editor of "Secrets of Home Theater and High Fidelity" was so stunned by his review sample he immediately bought one, as did his co-reviewer. I use this to drive the Audio Aero Prestige monoblocks which are arguably the world's finest amplifiers. To beat the sonics of this unit, be prepared to pay a lot of money. Please read the review below.