Unison Research Unico 90 - User Manual

Unico 90

Summary

Unpacking and Initial Setup

Acclimatization After Unpacking

Allow device to adapt to room temperature to prevent condensation damage.

Installation Guidelines

Placement and Ventilation

Ensuring safe placement, adequate clearance, and proper ventilation for the amplifier.

Power Connection

Mains Voltage and Fuse Information

Details on mains voltage settings and fuse replacement procedures.

Operation and Features

Switching On and Warm-Up

Guidance on powering up, initial start-up phase, and warm-up indications.

LED Indicator Meanings

Understanding the status indicated by the amplifier's LED lights.

Remote Control Usage

Instructions for operating the amplifier using the infrared remote control.

Audio Outputs and Bypass Input

Description of line outputs and the bypass input function.

Fuse Specifications

Internal Fuse Details

Listing of internal fuse types, values, and sizes.

Safety and Maintenance

General Safety Precautions

Important warnings regarding operation, opening the unit, and liquid spills.

Valve Replacement and Cleaning

Guidelines for replacing vacuum tubes and cleaning the amplifier.

Technical Specifications

Detailed Performance Metrics

Comprehensive technical data including output power, frequency response, and dimensions.

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The Unico 90 is an audio component from Unison Research, a company known for its extensive electronic design experience and deep knowledge of vacuum tubes. This product is a testament to their passion for crafting unique and valuable audio equipment that harmoniously blends traditional craftsmanship with advanced electronics. Each Unico 90 unit is built using high-quality components and materials, undergoing careful inspection at various production stages and rigorous testing to meet stringent reliability and quality standards.

Function Description:

The Unico 90 functions as an integrated amplifier, designed to amplify audio signals for a high-fidelity listening experience. It incorporates a hybrid design, utilizing both vacuum tubes and Mosfet technology in its amplification stages. The amplifier features a dual-mono, zero-feedback, two-stage valve-Mosfet integrated design, which contributes to its unique sound characteristics.

The input stage of the Unico 90 is a pure Class A, double triode totem pole ECC83 and parallel totem pole ECC81 configuration. This particular circuitry allows the single input stage to amplify the input signal and directly drive the power stage. The output stage is a Class AB thermostable design, employing complementary Hexfet transistors (three pairs per channel). This two-stage architecture, consisting of an input stage and an output stage, utilizes only local feedback, a design choice that influences its sonic signature.

The Unico 90 offers multiple input options, including six line inputs (three unbalanced, two balanced, and one "bypass" unbalanced input). The "bypass" input is a distinctive feature that allows the Unico 90 to be used solely as a power amplifier. When this input is selected, the audio signal bypasses the input selector and volume control, going directly to the mainboard. This is particularly useful for integrating the Unico 90 into a home theater system or with a preamplifier that has its own volume control.

For outputs, the amplifier provides a "sub out" and a "monitor" output. The "sub out" delivers a buffered audio signal from the selected input, with its level determined by the volume control, and is not limited in band. The "monitor" output also provides a buffered audio signal from the selected input. Additionally, the Unico 90 supports bi-wiring with its 4+4 output connectors.

Usage Features:

Operating the Unico 90 involves a straightforward process, but with important considerations for optimal performance and longevity. Upon unpacking, it is crucial to allow the device to adapt to room temperature for several hours to prevent condensation, which could cause damage.

Before switching on the amplifier, all connections should be made and checked. The volume control must be set to zero (fully anti-clockwise) and remain in that position until the initial automatic start-up phase is complete. The Unico 90 automatically initiates a warm-up phase upon switching on, indicated by blinking LEDs between the input selection and volume knobs on the front panel. During this phase, the output stages are disabled. While the working temperature for the tubes is reached in less than 40 seconds, best results are typically achieved after approximately 10 minutes from switch-on.

The front panel features a selector knob for input selection, a volume knob for audio level adjustment, and LED indicators for both input and volume status. An IR receiver is also present for remote control operation. The main power switch is located on the side of the unit.

The LEDs provide important information about the amplifier's operating condition:

• LED INPUT and LED VOLUME ON: Indicates normal operation.
• LED INPUT and LED VOLUME blinking (fast): Indicates the automatic start-up phase (approximately 40 seconds).
• LED INPUT and LED VOLUME blinking (slow): Indicates the intervention of the thermal protection device, at which point the power stage is switched off. The amplifier will automatically switch on and repeat the initial start-up phase once the internal temperature returns to normal. It is advisable to switch off the amplifier if this occurs to speed up the return to normal operation.
• LED INPUT ON and LED VOLUME blinking: Indicates that the amplifier is receiving a signal from the IR remote control (specifically, volume changes).

In the event of a temporary loss of mains electricity, even for a very short duration, the amplifier will restart in automatic start-up mode.

The remote control handset, supplied with the amplifier, uses a CR2032 3V lithium battery. It allows for volume control using the Vol- and Vol+ buttons.

When using the "bypass" input, it is critical to connect and select this input with the amplifier turned off and the source volume set to minimum. The source should be turned on first, followed by the Unico 90. Selecting this input while the amplifier is already turned on may produce noise during switching. This input should only be selected if it is actually connected to a source.

Maintenance Features:

Proper maintenance is essential for the Unico 90's performance and longevity.

• Safety First: Never operate the device with either the bottom or top covers removed. The amplifier contains no user-serviceable parts inside, and any technical assistance or product service should be referred to an Authorized Dealer or a Unison Research authorized Service Centre.
• Liquid Spills: In case of accidental liquid spills, immediately remove the mains plug from the wall socket and seek assistance from an authorized Service Centre before attempting to operate the unit again.
• Power Connection: Before inserting the mains plug into the wall socket, ensure that the switch on the amplifier is in the "OFF" position.
• Valve Replacement: The Unico 90 uses two ECC83 (12AX7) and four ECC81 (12AT7) valves. Valve replacement should only be carried out using valves of the same type and matched in pairs. The amplifier has been designed for maximum valve life, with laboratory tests exceeding 1500 hours of life. Before attempting valve replacement, ensure the amplifier is switched off and the mains power cord is removed. If in doubt, consult an Authorized Dealer or Service Centre.
• Cleaning: Cleaning should be performed after switching off the device and allowing the amplifier to cool down. Use a soft, dry cloth. Avoid using solvents or alcohol-based detergents, and do not rub hard on the screen-printed legends.
• Ventilation: Never operate the amplifier when covered. Adequate ventilation is essential at all times to prevent overheating.
• Fuses: The Unico 90 contains twelve fuses, including main fuses. The main fuses are rated at 10AT / 250V for 100V/120V mains voltage or 6.3AT / 250V for 220V/230V/240V mains voltage. All fuses are 5 x 20mm glass fuses. If a fuse blows, it is advised to consult an Authorized Dealer or Service Centre for advice. Always replace fuses with new ones of the same type and value. The voltage setting is factory-set and cannot be changed by the user. It is crucial never to connect the Unico 90 to AC mains if the local voltage does not match the value indicated on the rear panel.

Unison Research Unico 90 Specifications