Unison Research Sinfonia
Best valve amplifier for audiophiles seeking rich, pure Class-A sound.
Experience unparalleled audio fidelity with the Unison Research Sinfonia, a pure Class-A integrated valve amplifier designed for the discerning listener. This Dual Mono/Stereo amplifier delivers exceptional channel separation and sonic purity. It features meticulously selected ECC83 and ECC82 double triodes for pre-amplification, paired with KT88 valves in a single-ended ultra linear configuration for its power stage. The Sinfonia boasts real-time bias compensation for stable performance, premium construction with wood damping elements, and dual toroidal transformers for clean, robust power delivery, ensuring a truly immersive listening experience.
$6499.00
Owner Satisfaction
4.7
/ 5
Category Rank
418
/ 1685
#418 in Power Amplifiers
Price vs Category Average
-21%
Below average
Type
Dual Mono/Stereo Integrated Valve Amplifier
/ Dual Mono/Stereo Integrated Valve Amplifier
Who it's for
- Minimalists desiring high-end performance in a single integrated unit
- Audiophiles seeking rich, emotive vocal and acoustic reproduction
- Design-conscious listeners wanting a beautiful, handcrafted centerpiece
Who should skip it
- Budget-focused buyers comparing value against solid-state alternatives
- Owners of low-sensitivity speakers in large listening rooms
- Users preferring low-maintenance, cool-running solid-state equipment
Performance breakdown
Sonic Purity
Pure Class-A operation delivers an exceptionally transparent and natural soundstage.
Channel Separation
Dual mono architecture ensures precise imaging and distinct instrument placement.
Build Integrity
Heavyweight construction and wood damping elements minimize unwanted mechanical resonance.
Tube Performance
KT88 valves provide a rich, warm, and harmonically complex listening experience.
Operational Stability
Real-time bias compensation maintains consistent performance without frequent manual adjustments.
Connectivity Versatility
Analog-focused inputs cater to purists but lack modern digital integration.
Key Specs
Type
Dual Mono/Stereo Integrated Valve Amplifier
Amplifier Class
Pure Class-A, Tube
Output Power
25W per channel
Frequency Response
20 – 30000 Hz
Input Impedance
47 kOhm
Output Impedance
4 – 8 ohm
Valves Used
4 x KT88, 2 x ECC82, 2 x ECC83
Net Weight
55 lbs
Features
- Pure Class-A operation for sonic purity
- Dual Mono design for superior channel separation
- KT88 output tubes for rich, detailed sound
- Real-time bias compensation for stable performance
- High-quality analog volume control
- Wood components for resonance damping
- Bi-wiring capable loudspeaker outputs
- Premium build with solid stainless steel controls
What customers say
The Unison Research Sinfonia is celebrated as a benchmark integrated tube amplifier, primarily for its exceptional sound quality. Owners consistently praise its rich, warm, and deeply musical presentation, noting outstanding midrange clarity that brings vocals to life with organic texture. This design virtually eliminates listening fatigue, making long sessions enjoyable. Users appreciate the flexible triode and pentode modes for tailoring the sound to their speakers. Furthermore, the Italian craftsmanship is highly regarded; its distinctive aesthetic, featuring quality wood and metal, makes it a visual centerpiece. While a significant investment, most users feel the immersive musical experience fully justifies the premium cost, viewing it as a long-term component.
Know before you buy
The Dual Mono design means the left and right channels are powered by independent circuits. This significantly improves channel separation, resulting in a wider, more precise soundstage and reduced crosstalk between channels.
No, the amplifier features real-time bias compensation. This system automatically monitors and adjusts the bias, ensuring the KT88 valves operate at peak performance and stability without manual intervention.
Yes, the Sinfonia includes a dedicated subwoofer output. This allows you to easily integrate a powered subwoofer into your system to extend the low-frequency response.
Yes, the loudspeaker outputs are designed to be bi-wiring capable. This allows you to use separate cables for the high and low-frequency drivers of your speakers, provided they support bi-wire connections.
No, the Sinfonia is a pure analog integrated amplifier and does not feature an internal digital-to-analog converter. You will need to use an external DAC if you intend to connect digital sources like streamers or CD transports.
At 55 lbs, the Sinfonia is quite heavy and requires a sturdy, stable surface for placement. Ensure your equipment rack or shelf can support this weight and provide adequate ventilation, as valve amplifiers generate heat during operation.
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$6499