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Musical Fidelity X-Tube #1
Musical Fidelity X-Tube variant 1
Musical Fidelity X-Tube variant 2

Musical Fidelity X-Tube

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X-Tube - Overview

We are proud to unveil the X-Tube – a revolutionary tube output buffer built with our newly reimagined X-profile aluminum die-cast chassis. This innovative design marks the return of the X-profile configuration, a distinctive element in the revered Musical Fidelity X10D tube output buffer and promises to breathe new life into a wide range of future audio electronics products.


Read Heinz Lichtenegger's Keynotes on the X-Tube here.

From X10D to X-Tube

The X10D, as designed by Musical Fidelity founder Antony Michaelson, is an acronym - or if you want “a wordplay” - for eX-(10)ten-(D) ded. Extended. The internal circuitry design faithfully follows the original and just like it, the new X-Tube extends your signal chain and is connected between input source and amplifier. It serves as an intermediary stage and is designed to enhance audio signal quality and add tube-like tonal characteristics to your line sources. Connectivity is simple, featuring 1x RCA input and 1x RCA output as well as an RCA bypass. The old external power supply has been reworked and moved into the chassis itself, allowing for a cleaner setup than before.

Advantages of a Tube Output Buffer and its Impact on Sound

Tube preamplifiers or tube output buffers hold a special place in the hearts of many audiophiles offering a distinct sonic signature that is prized by many audio enthusiasts. The warmer, more natural sound, improved dynamics, and potentially reduced listening fatigue contribute to a unique and engaging listening experience.

The X-Tube in Today’s Audio World

What is the place of the X-Tube in today’s audio world? We currently observe a surge in a new generation of affordable streaming devices and DACs. Even CD-players receive increased interest as people are holding on to their old collections.

These modern digital audio devices achieve great price points, but do this at the sacrifice of hardware. Software makes up most of their cost and there is no budget assigned to, amongst other things, proper output stages. Instead, cheaper integrated IC solutions are used that don’t have the power to properly drive line inputs in many amplifiers. The X-Tube has a clean, high impedance tube input, meaning it won’t put as much strain on the output drive capabilities of connected source devices. Regular line inputs on most amplifiers are usually more demanding and cheap output stages will struggle. On the output side, the X-Tube’s clean, low impedance tube output buffer has plenty of drive and will not struggle with any low or high impedance amplifier input. The X-Tube is designed to be the reliable core of your system, enhancing modern streamers and keeping pace as digital technology rapidly evolves. While streamers excel at software and deliver great digital-to-analog conversion with the latest DAC technology, they often fall short when it comes to analogue output potential. And when their analogue drive is lacking, the X-Tube complements them perfectly.

The Missing Link in Action

CD Players and DACs

The X-Tube adds tube like tonal characters, depth and richness to your digital CD or DAC sources.

Phono Stages

The X-Tube enhances analogue sources as well, and due to its ideal impedance characteristics makes the impact of audio cables less noticeable.

Streamers

Modern streamers have excellent software and apps, but to reach a certain price point take big hits in their hardware design. Low-quality output stages are often seen in the form of simple IC solutions. These output stages often struggle to properly drive line inputs in many amplifiers. The X-Tube’s clean, high impedance tube input is easy to drive even for these types of IC solutions.

Preamps

If you are unsure whether your preamp’s and power amp’s impedances are matching, the X-Tube can be used as an intermediary buffer stage, providing suitably high input impedance and low output impedance. The X-Tube is the ideal driver for low and high impedance amplifier inputs.

Home Theatre

The X-Tube enhances the front left and right stereo channels of an A/V receiver going into a multichannel power amp for high-fidelity stereo music listening.

The Missing Link FAQ

What is the X-Tube - The Missing Link?

The X-Tube is a pure Class A triode tube line stage. It dramatically improves the performance of any analogue or digital source to which it is connected.

How is it used?

All you have to do is take the analogue output from your existing source (any analogue or digital source) plug this into the inputs of the X-Tube and then plug the outputs of the X-Tube into your existing amplifier. You will find that there is a dramatic improvement in performance. The sound is sweeter, clearer and more dynamic. At the same time the bottom end is deeper and the imaging is greatly improved.

Come on! Who are you kidding? The Missing Link is just adding distortion, noise and altering the frequency response and therefore destroying the purity of the original.

This is not correct. The Missing Link’s measurements are as follows:

  • Distortion from 10Hz to 20kHz, less than 0.003%
  • Residual noise measured at full output, better than 96dB unweighted
  • Frequency response 20Hz to 80kHz + 0, - 0.3dB
  • Crosstalk better than 95d8.
    • Tube Output Buffer
    • Adds tube like tonal characters, depth and richness to every digital and line source
    • 2x E88CC triode tubes
    • Impedance matching amplifier
    • Maximise signal transfer
    • Reduces distortion due to wrong impedance matching
    • Protects your amplifier from reactive loads
    • Superior mechanical design
    • Musical Fidelity invented with the X-line a perfect super-anti-resonance free cabinet out of extruded aluminium
    • The X-Tube is the first product out of a series of X-products
    • Features
    • Dramatically improves any digital and analogue source
    • Enhancement for budget digital/streaming/CD sources that use all-in-one chip designs and lack proper output stages
    • Ultimate impedance matching if used between preamplifier and amplifier
    • Direct mains input, no external power supply allows for clean setup
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Overall Score 89/100

Rating for [object Object]

Nicely Roasted

Musical Fidelity X-Tube — Output Valve Buffer Stage

Musical Fidelity’s X-Tube is a compact, tube-based output buffer that injects warmth, clarity and dimensionality into modern source components. Finn de Kroon found it adds depth and smooth tonality while retaining impressive technical poise (20Hz–80kHz response, SNR >96dB). The twin E88CC triodes deliver lively, fast transients and confident dynamics that make bass punchy and mids bloom without sounding congested. Built from a one-piece aluminium extrusion with a brushed faceplate, the chassis offers strong EMI shielding and a refined, compact footprint. Connectivity is intentionally minimal — single RCA in/bypass/out — so it suits listeners seeking a tonal upgrade and impedance matching for streamers, DACs or budget CD players rather than those needing versatile I/O. At ~€599 the X-Tube is a high-value, musical buffer that elevates systems with tasteful tube character.

Best of High End

"The X-Tube adds a layer of tube-like warmth and clarity that elevates your listening experience."

Pros

  • Adds warmth, depth and enhanced clarity to lightweight or budget sources, improving tonal richness and overall musicality.
  • Fast transient response and strong macro/micro-dynamics thanks to the twin E88CC triode topology, delivering lively, punchy presentation.
  • Robust one-piece aluminium chassis and brushed faceplate provide excellent EMI shielding and a compact, well-finished build.
  • Excellent value for its role — at ~€599 it noticeably upgrades budget streamers/DACs and adds desirable tube character without large compromises.

&

Cons

  • Very limited connectivity (single RCA input, RCA bypass and single RCA output); no balanced I/O, digital inputs, remote or headphone output.
  • Introduces subtle tube coloration — musical and pleasing for many listeners, but not strictly neutral for those seeking absolute transparency.

Transparency

88/100

Reviewers note tube-derived warmth and depth but also report excellent technical specs (SNR >96dB, crosstalk >95dB and 20Hz–80kHz response), and no complaints of hiss or hum. The tube topology imparts a subtle coloration that is praised for musicality, so while the unit gets out of the way technically, it is not a colourless 'straight wire' reference.

Sound Quality

89/100

Dynamics

90/100

The review explicitly credits the E88CC triode design with fast transient response and good handling of macro- and micro-dynamics with minimal distortion. The single-ended tube output stage is presented as lively and punchy rather than compressed.

Soundstage Imaging

88/100

The X-Tube is reported to enhance depth and provide an immersive presentation; reviewers highlight improved sense of space and layering. There is limited specific commentary on extreme width or razor-sharp imaging, but depth and dimensionality are definite strengths.

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Build Quality

90/100

Constructed from a one-piece aluminum extrusion with a brushed faceplate, the unit is praised for solid construction and good shielding against EMI. The compact, well-finished chassis and attention to shielding contribute to perceived quality above its price point.

Features Connectivity

80/100

Very minimal I/O: single RCA input, RCA bypass and single RCA output; no balanced I/O, phono, DAC, headphone or remote. The review notes excellent impedance matching and a high-impedance input which aids compatibility, but feature set is intentionally basic (baseline active preamp score).

Value for Money

90/100

At ~€599 the reviewer frames the X-Tube as a 'game-changer' for improving budget sources, addressing common shortcomings of streamers/DACs and adding desirable tube character — language consistent with a justified-premium/value recommendation at this price.

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