Rega Solis Power Amplifier

Go to Extreme Sonic Lengths with Rega Solis: Hand-Built, British-Made Power Amplifier Features Fully Symmetrical Circuitry, 12 Sanken Output Transistors, and Two Toroidal Transformers to Offer Reference Playback

To what lengths will you go for high-quality audio? Rega engineers devoted four years to developing and fine-tuning the circuitry in the 168Wpc Solis power amplifier to ensure it operates with extreme levels of accuracy, engagement, and coherency. The most uncompromising amplifier to ever come out of Rega’s lab, the hand-built and British-made Mercury sports a fully symmetrical circuit throughout with a differentially driven, low-distortion, high-linearity and -bandwidth common base voltage amplifier driver stage. Such topology provides the necessary voltage swings to enable Solis to drive any speaker system with the minimum of distortion. Indeed, every aspect of this reference-grade component serves the music with profound obsessiveness.

Inside, a dozen (six per channel) Sanken 130-watt 15A, high-frequency, multi-emitter output transistors are used in a triple high-current output stage. The cascoded differential input amplifier uses two, low-noise, LED-referenced, current generators. The open and closed loop feedback levels and gain bandwidth product components produce a tight, controlled soundstage, especially in the low-frequency range. Other audiophile touches include Nichicon audio-grade capacitors in critical bypass and decoupling positions; HTR non-inductive resistors in the output stage; and polyester capacitors subbing for electrolytic types in several areas.

When it comes to the power supply, two, low-noise, custom, 330VA toroidal transformers comprised of high-grade fully bonded core material carry the day. The latter elements reduce mechanical noise from the transformer when the transformers are operating under arduous mains conditions with high levels of asymmetric mains distortion. Combined with 40,000µF of Rega K-Power smoothing capacitors per channel, the transformers provide ample current to drive the hardest of loads, effectively doubling the power into a four-ohms load from an eight-ohms load. All the power supplies utilize fast recovery rectifier diodes, giving rise to cleaner DC. The input and low-level driver stages are fed from a regulated symmetrical tracking power supply with a low-noise voltage reference, which provides a fully stabilized, low-noise voltage, underlining the commitment to sonic purity.

Offering balanced and unbalanced connectivity, the 54.7-pound Solis also boasts an extensive protection circuit that monitors the speaker DC levels and amplifier temperature. It works in conjunction with the supervisory circuit. Solis further uses microcontroller-based slow start, standby, and power supply supervisory circuits to power-up the two massive transformers from standby, keeping the in-rush current to a minimum. The supervisory circuits control the no-signal standby power down function. And take note: The slow start and power-supply supervisory microcontroller and protection circuits have their own dedicated power supply, galvanically isolating it from the audio.

Rounded out by a 12V trigger, user-selectable standby mode, and an independent Mute function, the 5.5 x 17 x 15-inch (HWD) Solis makes for a seamless match with the Rega Mercury preamplifier. A lifetime warranty against manufacturer defects gives you yet another reason to put this go-getter on your short list.

For more information, and to order yours, give us a call at 312-433-0200.

"The Solis is a work of audio art that has huge driving capability but has very little character, making it hugely transparent and revealing. The Mercury/Solis combination punches way above its price and anyone looking for serious amplification with a lifetime guarantee [should] put aside their prejudices and compare it with the best in class."
—Jason Kennedy, The EAR

Solis Background
Solis is the culmination of almost four decades of Rega engineering experience in solid-state amplifier development. This expertise, combined with the “clam shell” Elicit and Exon amplifier circuits, laid the foundations for the advanced amplifier circuit found in Solis. All components selected during the design process were chosen for their sonic and electrical properties. Rega has applied enhancements to the thermal stability and heatsinks of the previous version of the power amplifiers, along with state-of-the-art, surface-mount technology. When Solis is combined with the Aura phonostage and Mercury preamplifier, the listener will have a fully symmetric, discrete system from source to speaker.

Rega's Philosophy on Balanced and Unbalanced
For normal domestic hi-fi, Rega recommends the use of unbalanced connections, for optimum sound quality. The Mercury and Solis core circuits are unbalanced. Because of this, additional circuitry is needed to create a balanced system. Although the balanced input and output circuits in the Mercury are very high performance, additional circuits will always add some inherent noise/distortion to the signal. True balanced systems are widely used on professional audio equipment. This requires all parts of the amplification and cables to be running as a “balanced system." Balanced connections are used where long cable runs are necessary, particularly in studio and PA applications. They help to cancel unwanted noise pickup in the long runs of cable. This noise rejection is why balanced circuits are used in professional equipment. Balanced circuits do not offer an intrinsic increase in sound quality over unbalanced circuits, as is sometimes perceived within the hi-fi industry. Another attractive aspect of balanced systems is they use XLR plugs. These are physically larger and can have a subjectively better insertion feel than standard RCA-style plugs. This can often lead to perceived value and contact quality, where in practice, there is no objective improvement. The vast majority of hi-fi equipment is an unbalanced topology (also called single-ended). In most circumstances, balanced connections are inappropriate for domestic hi-fi equipment. The increased noise rejection is not necessary and does not outweigh the drawbacks of additional circuit complexity. On expensive equipment, balanced connections are sometimes provided for use in recording studios or to satisfy the perception that balanced connections are better. Rega knows that some of its products are used in the studio arena, so it added balanced XLR connections and implemented additional circuitry.