Unison Research Triode 25 Stereo Tube Integrated Amplifier
Best tube amplifier for audiophiles seeking versatile, high-fidelity sound.
Celebrate Unison Research's 25th anniversary with the Triode 25 Integrated Tube Amplifier, a refined evolution of the acclaimed Triode 20. This push-pull design utilizes EL34 output tubes, offering flexible operation in both Triode and Pentode modes. Experience up to 45W per channel in Pentode for dynamic power, or enjoy the nuanced sound of 25W per channel in Triode mode. Featuring a built-in USB DAC, four Line inputs, and Tape/Sub outputs, it seamlessly integrates into your audio setup. Available in elegant Cherry or Black finishes, this 20 Kg amplifier delivers exceptional audio fidelity with minimal distortion.
$4999.00
Owner Satisfaction
4.7
/ 5
Category Rank
418
/ 1685
#418 in Power Amplifiers
Price vs Category Average
-39%
Below average
Output Power
.45..25
/ Approx watt per channel in Ultralinear (Pentode) configuration Approx watt per channel Triode configuration
Who it's for
- Design-conscious listeners wanting a sophisticated visual statement piece
- Audiophiles seeking customizable sound profiles for different musical genres
- Music lovers craving the classic, rich warmth of vacuum tubes
Who should skip it
- Listeners with low-sensitivity speakers requiring high-wattage amplification
- Budget-focused buyers wary of recurring tube replacement expenses
- Users with small, poorly ventilated rooms or heat-sensitive setups
Performance breakdown
Sonic Versatility
Switchable triode and pentode modes offer two distinct, high-fidelity sound profiles.
Build Integrity
Substantial twenty-kilogram chassis ensures resonance-free performance and long-term durability.
Connectivity Integration
Built-in USB DAC simplifies digital streaming without sacrificing analog warmth.
Power Delivery
Robust EL34 tubes provide ample headroom for driving most demanding speakers.
System Flexibility
Dedicated sub and tape outputs allow for seamless multi-component system expansion.
Harmonic Purity
Advanced circuit design minimizes odd-order distortion for a natural, liquid presentation.
Key Specs
Output Power
Approx. 45 watt per channel in Ultralinear (Pentode) configuration. Approx. 25 watt per channel Triode configuration
Output Impedance
6 Ohm
Inputs
4 Line (1 Tape), 1 USB DAC
Input Impedance
47 kOhm / 50 pF
Outputs
1 Tape out, 1 Sub Out
Negative feedback
5 dB or 1.8 dB
Valve complement
2 x ECC83, 1 x ECC82, 4 x EL34
Power Consumption
300 watt max
Features
- Switchable Triode and Pentode operation
- Push-pull design with EL34 tubes
- Integrated USB DAC input
- High power output in Pentode mode
- Symmetrical output transformer
- Low odd-order harmonic distortion
- Available in Cherry or Black finish
- Tape out and Sub Out connections
What customers say
Audiophiles cherish the Unison Research Triode 25 for its exceptional musicality. The sound signature is consistently praised as warm, rich, and deeply engaging, especially in the midrange, delivering natural timbre and emotional depth. A key feature is the flexible Triode and Pentode operation, allowing users to tailor the sound for intimate listening or driving demanding speakers. Beyond performance, the Italian craftsmanship and elegant design, featuring visible tubes and wood accents, are highly regarded. While a significant investment, owners feel the superior sonic experience justifies the cost. It is celebrated as a component that transforms listening into an immersive, high fidelity experience.
Know before you buy
Triode mode offers a more nuanced, intimate sound signature with 25 watts per channel, while Pentode mode provides 45 watts per channel for greater dynamic power and drive. You can easily switch between these modes to best suit your music genre or speaker sensitivity.
Yes, the Triode 25 features a dedicated Sub Out, allowing you to integrate an active subwoofer into your stereo system for extended low-frequency performance.
The integrated USB DAC allows for a direct digital connection from your computer, serving as a convenient high-quality interface for your digital music library without needing an external converter.
With an output impedance of 6 Ohms, this amplifier is designed to drive a wide range of bookshelf and floorstanding speakers. Its push-pull EL34 tube design is particularly well-regarded for its ability to balance detail with a warm, musical presentation.
The amplifier measures 30 cm by 45 cm with a height of 20 cm and weighs 20 kg. Because it is a tube amplifier, ensure you place it on a sturdy surface with adequate ventilation space above and around the unit to allow heat to dissipate properly.
Yes, the Triode 25 allows you to select between two levels of negative feedback, 5 dB or 1.8 dB. This adjustment lets you fine-tune the amplifier's damping factor and overall sound character to better match your specific speakers.
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