Unison Research Phono One Tube Preamplifier
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Unison Research Phono One Tube Preamplifier
The Unison Research Phono One has always been a beloved choice among audiophiles, earning a reputation for its timeless design and superior sound quality. Recognizing the continuous demand for this classic, Unison Research has reintroduced the Phono One, blending the cherished aesthetics of the original with modern technological enhancements that push the boundaries of audio fidelity.
Key Features
- Ten Triode Design: Utilizes 5 ECC83/12AX7 double triodes in parallel for reduced noise and distortion.
- 54dB Gain: Compatible with all MM and most MC cartridges, providing ample amplification.
- Precise RIAA Equalization: Features a passive network with carefully selected components for accurate sound reproduction.
- Selectable Input Impedance: Allows matching of resistance and capacitance to your cartridge for optimal performance.
- Advanced Power Supply Design: Independent RC filter cells minimize cross-talk and enhance channel separation.
- Handcrafted Quality: Includes hand-soldered wiring, oversized power components, and enhanced cooling for long-term reliability.
About Unison Research
Unison Research, founded in Italy, has a long-standing reputation for crafting high-fidelity audio equipment that marries traditional craftsmanship with cutting-edge technology. Each product reflects their passion for music and dedication to producing equipment that delivers both sonic excellence and visual beauty.
Timeless Design Meets Modern Engineering
While the exterior of the Phono One remains faithful to its original, elegant form, the internal circuitry has been significantly upgraded. The inclusion of ten triodes (5 ECC83/12AX7 double triodes) configured in parallel achieves exceptional noise reduction and distortion control. This enhancement also boosts the overall gain to approximately 54dB, making it versatile for use with a wide range of cartridges.
The Phono One employs a meticulously selected passive RIAA network, ensuring precise adherence to the equalization curve. Upgraded output capacitors further improve bandwidth and minimize phase rotation at low frequencies, delivering a sound that's both expansive and intricately detailed.
Precision and Flexibility
Understanding the critical nature of cartridge matching, the Phono One offers selectable input resistance and capacitance, allowing for a tailored fit to any cartridge’s requirements. A dedicated spot on the PCB is reserved for custom resistor values, ensuring that even the most discerning audiophiles can fine-tune their setup for optimal performance.
The power supply design is another area where the Phono One excels. With independent RC filter cells for each gain stage, it dramatically reduces cross-talk, achieving nearly immeasurable low-frequency interference at less than -90dB. This meticulous attention to detail extends to the layout design, which enhances channel separation and interference rejection, culminating in an audio experience of exceptional natural detail and musical clarity.
Craftsmanship Without Compromise
Every aspect of the Phono One reflects Unison Research’s commitment to quality. From the hand-soldered signal wiring to the placement of tubes designed to minimize microphonic distortions, no detail has been overlooked. Oversized power components and proper cooling measures ensure long-term reliability, making the Phono One not just a piece of equipment, but a lasting investment in high-fidelity audio.
The Listening Room Difference
Your listening space is unique, and so are your needs. That's why we take the time to understand your preferences, your room acoustics, and your sonic dreams. We'll guide you through our range of hi-fi options, ensuring you find the perfect match for your space and budget. We believe in personal connections, exceptional service, and expert advice because when it comes to sound, there's no one-size-fits-all solution. Contact us to learn more.
Specifications
| Type | Stereo Phono Valve Preamplifier |
| Class | Pure A |
| RIAA | Passive +/- 0.1 dB (20 Hz - 20 kHz) |
| Output Impedance | 800 ohms |
| Outputs | 1 x Line |
| Gain | 54 dB |
| Total Harmonic Distortion (THD) | 0.1% at 1V output |
| Signal to Noise Ratio (S/N) | –80 dB |
| Inputs | 1 per MM or MC phono cartridge |
| Input Impedance | 47 kOhm, 100, 50, 22 ohms / 100, 200, 320, 420 pF (modifiable) |
| Feedback Factor | 0 dB |
| Valves | 5 x ECC83 / 12AX7 |
| Power Supply | External |
| Dimensions | 37.3 x 5.84 x 24.63 cm |
| Net Weight | Approx. 3.6 kg (including power supply) |
Unison Research Phono One or Simply Phono: what does the Phono One add?
Unison Research Phono One or Simply Phono: what does the Phono One add?
Both are Unison Research tube phono stages with a passive RIAA network and zero feedback, so the difference is in the details. The Phono One runs five ECC83/12AX7 tubes where the Simply Phono runs four, and it has 54dB of gain against 52dB. It also adds selectable capacitance (100, 200, 320 or 420pF) where the Simply Phono is fixed at 100pF, and Unison quotes tighter RIAA accuracy (plus or minus 0.1dB against 0.2dB), lower distortion (0.1% against 0.4% at 1V out) and a better signal to noise ratio (80dB against 72dB).
Will the Phono One work with a low-output moving coil cartridge?
Will the Phono One work with a low-output moving coil cartridge?
Check your cartridge's output first. Unison Research specifies the input for moving magnet cartridges and for high-output moving coils above 2mV, and its manual describes the 54dB of gain as compatible with most MM and MC cartridges. Resistive loading of 100, 50 or 22 ohms is there for moving coils. If your moving coil is well under 2mV, Get in touch with Mike before you order so the pairing is checked.
How do I set cartridge loading on the Phono One?
How do I set cartridge loading on the Phono One?
With the pair of DIP switches next to the input connectors on the rear panel. They set both the resistive and the capacitive part of the load, and Unison prints the reference table for the switch positions on the rear panel itself. Unison lists 47k, 100, 50 and 22 ohms for resistance and 100, 200, 320 and 420pF for capacitance. Your cartridge maker's recommended load is the starting point.
Does the Phono One need to warm up before I play a record?
Does the Phono One need to warm up before I play a record?
It handles that itself. At switch-on the front LED lights orange and the outputs stay muted while the tubes warm up. After about 30 seconds the LED turns green and the outputs switch on. Unison asks that the volume on the rest of the system sits at zero before you switch on and stays there until the start-up phase finishes. Keep it off the top of a power amplifier or any other heat source, too.
What tubes does the Phono One use, and how long do they last?
What tubes does the Phono One use, and how long do they last?
Five ECC83 (12AX7) double triodes. Unison says the circuit was designed for maximum tube life and that its laboratory tests passed 1,500 hours. Replacements should be the same type, matched in pairs, and fitted with the unit switched off and the mains cord removed.
