Unison Research PRELUDIO Class A Integrated Stereo Tube Amplifier at Vinyl Sound Buffalo, NY USA

The PRELUDIO is a Class A single-ended integrated valve amplifier from Unison Research (Treviso, Italy), available at Vinyl Sound in Buffalo, NY, USA. Sharing its visual and architectural DNA with the higher-tier Sinfonia and Performance amplifiers while offering an accessible entry point into the Unison Research classic line, the PRELUDIO produces 14 watts per channel through two KT88 output tubes in a single-ended ultralinear Class A output stage. Its amagnetic stainless steel top plate eliminates magnetic interference with the output stage operating at high current, and all five inputs use gold-plated connectors. An RC2 remote control and premium Cherry Wood finish are included as standard, reflecting Unison Research's Italian design philosophy across even the most affordable tier of the classic integrated amplifier range.

Single-Ended KT88 Class A Topology

The PRELUDIO uses two KT88 beam tetrode output tubes in a single-ended ultralinear configuration -- one tube per channel -- operating in pure Class A. The KT88's bias setting in the PRELUDIO is calibrated for optimal operating point consistency over many years of tube life, contributing to both long-term sonic stability and minimized warm-up time from a cold start. Unlike EL34-based single-ended designs, the KT88 in this topology provides a somewhat firmer, more extended bass character alongside a full and engaging midrange. The preamplifier stage uses two ECC82 dual triodes in dedicated per-channel stages -- each channel has its own complete pre-amplification, driver, and output stage -- ensuring maximum channel independence and stereo separation. Feedback is set at 10 dB for a balanced compromise between frequency stability and the open, immediate quality of the output stage's Class A character.

Amagnetic Steel, Gold-Plated Inputs, and Cherry Wood Finish

Unison Research pays particular attention to the materials and construction details of the PRELUDIO. The top plate is manufactured from amagnetic stainless steel -- a non-ferrous alloy that does not concentrate or distort the magnetic fields generated by the KT88 output tubes' transformers, preventing hysteresis-induced noise from propagating into the chassis or signal wiring. All five gold-plated RCA inputs maintain stable, oxidation-resistant contact across the range of temperatures generated by a Class A amplifier in continuous operation. The front panel is finished in Cherry Wood, a material specification that places the PRELUDIO in visual continuity with the higher-tier Sinfonia and Performance models. A subwoofer RCA output enables integration with a powered bass supplement without interrupting the signal to the main loudspeaker outputs.

Key Features

• 14 W/Channel Single-Ended KT88 Class A: One KT88 output tube per channel in pure Class A ultralinear operation delivers 14 watts with the tonal richness associated with single-ended amplification.
• Amagnetic Stainless Steel Top Plate: Non-ferrous steel construction eliminates magnetic interference from the KT88 output stage on the chassis and internal wiring.
• Dedicated Per-Channel Circuit Stages: Separate pre-amplification, driver, and output stages per channel ensure maximum stereo separation and channel independence.
• Gold-Plated Inputs: All five RCA inputs use gold plating for stable, low-resistance contact over the amplifier's operational lifetime.
• Cherry Wood Front Panel: Premium Cherry Wood finish continues the visual design language of the Unison Research classic amplifier family.
• Subwoofer Output: Dedicated RCA subwoofer output for powered bass supplement integration.
• RC2 Remote Control Included: IR remote for input selection and volume from the listening position.
• 15 Hz - 50 kHz Frequency Response: Extended response below and above the standard audio band supports high-resolution playback formats.

Technical Specifications

Frequently Asked Questions

What is the Unison Research PRELUDIO?

The Unison Research PRELUDIO is a Class A single-ended integrated valve amplifier from Treviso, Italy, using two KT88 output tubes to produce 14 watts per channel in a single-ended ultralinear output stage. It features four line inputs, a tape input, a subwoofer output, gold-plated connectors, amagnetic stainless steel top plate, Cherry Wood front panel, and RC2 remote control. Its frequency response spans 15 Hz to 50 kHz.

How does the PRELUDIO compare to the Unison Research Simply Italy?

The PRELUDIO and Simply Italy are both entry-level single-ended Class A integrated amplifiers in the Unison Research lineup, but they use different output tubes and power levels. The Simply Italy uses two EL34 tubes producing 12 watts per channel with selectable feedback of 5 dB or 1.8 dB and a self-biasing output stage. The PRELUDIO uses two KT88 tubes producing 14 watts per channel with 10 dB feedback and the amagnetic steel top plate and gold-plated inputs of the classic line aesthetic. The PRELUDIO offers slightly more power, a gold-plated input standard, and Cherry Wood finish; the Simply Italy is the lighter and lower-power design at 15 kg versus the PRELUDIO's 18 kg.

Can the PRELUDIO drive moderate-sensitivity loudspeakers?

Yes. At 14 watts per channel in Class A, the PRELUDIO is suitable for loudspeakers of 88 dB sensitivity or higher in small to medium rooms. Within the Unison Research range, the MAX MINI (93 dB) and MAX 1 (94 dB) pair well. For larger rooms or lower-sensitivity loudspeakers, the Sinfonia (25 W) or Performance Anniversary (45 W) offer greater output headroom. The 6-ohm output impedance is optimized for loudspeakers presenting a nominal 8-ohm load.

What is the KT88 tube, and why does the PRELUDIO use it?

The KT88 is a beam tetrode output tube originally developed by Marconi-Osram Valve in the UK. In audio amplification, the KT88 is associated with a firmer, more extended bass response and a somewhat more neutral tonal character than the EL34, while sharing the warmth and harmonic richness characteristic of output valves in Class A single-ended configurations. Unison Research specifies the KT88 in the PRELUDIO for the same reasons it appears in the Sinfonia and Performance -- the tube's characteristics align with the brand's sonic aims across its classic integrated amplifier line.

Where can I buy the Unison Research PRELUDIO in Buffalo, NY or the USA?

The Unison Research PRELUDIO is available at Vinyl Sound in Buffalo, NY, USA. Vinyl Sound is an authorized Unison Research dealer serving customers across western New York and the United States. Contact the Vinyl Sound team for current availability and system-matching advice.