The Tube Distinctions KT-150 Copper Valve Amplifier - Review

The Tube Distinctions KT-150 Copper Power Amplifier combines an iconic bespoke copper chassis with advanced valve engineering to deliver a commanding, high-fidelity audio performance.

Discover more about the fabulous Tube Distinctions KT-150 Copper Power Amplifier

T he Tube Distinctions Copper Amp is my current amplifier of choice. Sitting neatly between my Croft Epoch Elite preamplifier and the 15" Tannoy Monitor Gold Lockwood Major loudspeakers, it doesn’t just fill a gap — it commands attention. Sonically and visually, the Copper makes its presence felt.

Designed and made in South Wales, England by Anthony Matthews, the Copper amplifier brings a new dimension to music with expression, authority and emotion.

For more information on the Croft Epoch Elite preamplifier, click HERE!

Construction

The main chassis is made from pure copper. Beautifully manufactured in Wales — a place where copper has a genuine industrial heritage — the chassis forms the foundation for the entire amplifier and houses all of the substantial transformer ironwork.

Being constructed from copper naturally helps reduce coupling effects from the power supply while also acting as an extremely effective heat sink. The engineering is every bit as impressive as the visual presentation.

From an outside perspective it simply looks extraordinary. Some may prefer the copper polished bright, but for me the amplifier looks best once the surface begins to oxidise naturally and develop character.

Anthony’s other products, including the Soul series amplifiers, are equally impressive. The transformer ironwork here is supplied by Sowter in the UK — one of the most respected transformer manufacturers in the world.

There are four transformers in total. The substantial main power transformer sits centrally between a pair of large output transformers, while a separate choke transformer is mounted directly behind the mains unit.

Heavy-duty carry handles are mounted either side of the output transformers and are absolutely necessary because the Copper amplifier weighs approximately 40kg.

On the rear is an HT switch allowing the amplifier to enter a standby-like sleep mode. There are also independent feedback adjustment potentiometers for each channel, allowing fine tuning of the amplifier’s presentation.

Valves

Before discussing the valves themselves, it’s worth mentioning my previous amplifier. It too was Tube Distinctions related — a heavily modified Pure Sound A30 upgraded by Anthony Matthews with a huge external power supply to minimise coupling effects from the internal transformer arrangement.

That amplifier used KT-88 and KT-120 output valves and sounded exceptional.

The Sound

As standard, the Copper amplifier can run KT-88 or KT-120 valves alongside 6SN7 drivers and GZ34 rectifiers, producing over 30 watts per channel of pure Class-A power.

With upgraded internal components including ClarityCap MR capacitors and a move to KT-150 output valves together with 5U4GB rectifiers, the amplifier moves into another performance category entirely.

The upgraded specification now produces approximately 50 watts per channel of pure Class-A valve power, which is more than enough for a pair of Tannoy Monitor Gold loudspeakers.

For more information on the Tannoyista Tannoy Monitor Gold crossovers, click HERE!

The Copper gives the Tannoys grip unlike almost any amplifier I have heard before. Partnered with quality analogue and digital sources, the sound becomes expansive, layered and effortlessly musical.

For more information on the Lockwood Major loudspeakers, click HERE!

Its timing, pace and dynamic authority ensure that this beautiful copper monster remains endlessly engaging. It delivers scale and realism without ever sounding forced or fatiguing.

The price for this particular specification is approximately £5000. More information can be found directly through Tube Distinctions below.

Tube Distinctions website: https://tubedistinctions.co.uk/

Frequently Asked Questions

Why does the copper chassis matter?

Copper naturally helps reduce electromagnetic interaction from the large transformers and power supply sections inside the amplifier. It also dissipates heat extremely effectively. Beyond the technical advantages, the copper chassis gives the amplifier a distinctive visual presence unlike almost any modern production amplifier.

How powerful is the Tube Distinctions Copper amplifier?

In upgraded KT-150 specification the amplifier produces around 50 watts per channel of pure Class-A valve power. Combined with the massive transformer design and current delivery, it drives large loudspeakers with exceptional authority and grip.

What valves does the amplifier use?

The amplifier can run several output valve configurations including KT-88, KT-120 and KT-150 valves. It also uses 6SN7 driver valves and upgraded rectification stages depending on final specification and tuning preferences.

How does it compare to conventional valve amplifiers?

The Copper amplifier combines traditional valve fluidity with unusually strong bass control, timing precision and large-scale dynamics. It avoids the soft or overly warm presentation often associated with older tube amplifiers while retaining tonal richness and realism.

Is it suitable for Tannoy Monitor Gold loudspeakers?

Absolutely. The amplifier pairs exceptionally well with large dual-concentric Tannoy systems, particularly Monitor Golds and Lockwood cabinets. Its control, scale and harmonic texture allow the Tannoys to perform with outstanding realism and effortless musicality.

About the Author

Reviewed by Josie — analogue audio specialist and long-term enthusiast of valve amplification, vintage studio equipment and high-performance loudspeaker systems. With over 30 years of hands-on experience restoring, modifying and evaluating classic audio components, Josie brings a detailed, real-world perspective to every review.