Musical Fidelity X-Tube Tube Output Buffer

A Tube Stage Between Your Source and Your Amplifier

The X-Tube sits in your signal path between a source — CD player, streamer, DAC — and your preamp or integrated amplifier. Analog out from the source, into the X-Tube, out to the amp. Nothing else in your system changes.

Inside are two 6922/E88CC triode tubes running in pure Class A, arranged so both process the entire signal single-ended. The chassis is Musical Fidelity's reimagined X-profile die-cast aluminum, with the power supply built in rather than hanging off a wall-wart the way the original X-10D did.

The Problem It Was Designed to Solve

Affordable streamers, DACs, and CD players often spend their budget on the digital side and economize on the analog output stage — typically an inexpensive integrated circuit that struggles to drive the varied inductive, capacitive, and resistive load a real amplifier and cable present.

The X-Tube presents a clean, high-impedance input that's an easy load for a modest output stage to drive. Its own low-impedance output then handles your amplifier's input without difficulty, high or low impedance. If your source has a weak output stage, that impedance buffering is the concrete, technical part of what this box does.

What the Tubes Contribute — Honestly

Tube stages add small amounts of even-order harmonic content, which many listeners perceive as warmth, richness, or added dimension. Musical Fidelity is candid that the X-Tube measures cleanly — better than most source devices, with signal-to-noise above 96 dB unweighted and no meaningful change to frequency response.

So set expectations accordingly. This is a subtle, character-shaping device, not a transformation. Whether you prefer the result is a matter of taste rather than accuracy, and taste is best settled by listening in your own system. Some owners find it makes digital sources less fatiguing over long sessions; others prefer their signal path unaltered. Both are reasonable positions.

A Design With Real History

Musical Fidelity has been building tube buffers since the 1990s, when founder Antony Michaelson's X-10D became one of the most widely sold audio accessories ever made — roughly 50,000 units worldwide. The X-Tube follows that circuit closely in a new chassis with an internal supply.

Before You Order

Single-ended RCA only. The X-Tube has no balanced XLR connections. If your source and amplifier are connected balanced, you'll need adapters or an RCA path through that part of your system. Call us if you want help working out where it fits.

It adds a stage, not a replacement. The X-Tube doesn't replace your preamp or provide volume control — it's an intermediary buffer that sits ahead of your existing amplification.

Specifications

• Type: Pure Class A tube output buffer
• Tubes: 2 × 6922 / E88CC triode
• Topology: Single-ended; both tubes process the full signal
• Input: High impedance, RCA
• Output: Low impedance, RCA
• Signal-to-noise ratio: Greater than 96 dB unweighted, referenced to full output
• Power supply: Internal
• Chassis: X-profile die-cast aluminum
• Weight: Approximately 5 lbs

Frequently Asked Questions

Will this fix a bright or harsh-sounding system?
It may soften the presentation somewhat, but a buffer isn't a tone control and won't correct a real system mismatch. If brightness is coming from speaker placement, room acoustics, or a genuine incompatibility between components, address that first — we're happy to talk it through before you spend money on the wrong solution.

Where exactly does it go?
Between your source's analog output and a line-level input on your preamp or integrated amplifier. It's most likely to help with a source whose analog output stage is a weak point — a budget streamer or DAC, or an older CD player.

Will I need to replace the tubes?
Eventually, as with any tube equipment. The 6922/E88CC is a common, widely available type with plenty of options if you later want to try rolling different tubes for a slightly different character.

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