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What You Need to Know
What Is the M6si500, and What Does It Do?
An integrated amplifier combines a preamplifier and a power amplifier in one box. The preamplifier handles source selection and volume control. The power amplifier takes that signal and amplifies it with enough force to drive your speakers. Most integrated amplifiers are a single amplifier circuit shared between both channels. The Musical Fidelity M6si500 is different.
Inside the M6si500, Musical Fidelity has built what amounts to a separate preamp and two independent monobloc power amplifiers — all sharing one chassis. Each channel has its own dedicated heatsink and its own transformer. The preamp section has its own independent power supply winding. This is a genuine dual-mono design, which means the left and right channels are kept completely separate from power supply to output, reducing crosstalk and delivering better channel separation, wider stereo imaging, and a quieter background.
The result is 500 watts per channel into 8 ohms of clean, stable power. That is an enormous amount of headroom. You will almost certainly never use all of it at once, but having that much power in reserve means the amplifier is never straining, never clipping, and never running out of breath during dynamic peaks in your music. It drives speakers effortlessly, even the most demanding designs.
Why 500 Watts Matters — Even at Low Volumes
You might wonder why anyone needs 500 watts per channel. The answer is not about volume — it is about dynamics and control. Music is not a constant signal. It has quiet passages, sudden crescendos, hard transients from drums and percussion, and deep bass notes that demand enormous current. An amplifier with vast power reserves handles these demands without flinching. The music sounds relaxed, open, and effortless because the amp is never working hard.
Each channel of the M6si500 uses 12 large bipolar output transistors capable of delivering 200 amps peak-to-peak. This is not just about watts — it is about current delivery. Speakers with complex crossovers, low impedance dips, or demanding phase angles are no problem for the M6si500. It will drive virtually any loudspeaker on the market.
Precision at Every Level — The Volume Control
The M6si500 uses a precision digital volume control with laser-trimmed substrate resistors. This is important because it ensures perfect channel tracking — the left and right channels stay precisely matched — even at very low listening levels. Many amplifiers lose balance at low volumes because their volume controls are imprecise. The M6si500 does not have this problem.
Who Is This Best For?
You own speakers that are hard to drive — low impedance, low sensitivity, or complex crossover designs — and need an amplifier that can handle them without breaking a sweat.
You want the performance of separates (separate preamp and monobloc power amps) in the convenience and footprint of a single chassis.
You value effortless, dynamic sound — the kind of relaxed authority that comes from having massive power reserves, even when listening at moderate volumes.
You want a pure analog amplifier — no built-in DAC, no streaming, no phono stage — just a focused, uncompromised amplification path.
You want to integrate a high-quality two-channel amp into an existing home theater setup using the Aux/HT bypass input.
How Does It Connect to Your System?
Inputs (rear panel): Four pairs of line-level RCA inputs labeled CD, Tuner, Aux/HT, and Tape. One pair of balanced XLR inputs for sources with balanced outputs (like high-end DACs or CD players). The Aux/HT input doubles as a home theater bypass for integration with a surround sound processor.
Outputs (rear panel): One pair of pre-outs (variable, volume-controlled) for connecting a subwoofer or recording device. One pair of fixed outputs. Four sets of high-quality speaker binding posts (two per channel for bi-wiring).
Important: The M6si500 is a pure analog amplifier. It does not include a built-in DAC, phono stage, or headphone amplifier. If you listen to vinyl, you will need a separate phono preamp. If you listen to digital sources, you will need a separate DAC or a source with analog outputs. If you need help building your system, give us a call at 800-942-0220.
Also note: the M6si500 weighs 30 kg (66 lbs). Plan for a sturdy rack or shelf, and you may want a second pair of hands for unpacking and placement.
What’s in the Box
- Musical Fidelity M6si500 Dual Mono Integrated Amplifier ×1
- Remote control ×1
- IEC power cord ×1
- Owner’s manual ×1
What the Pros Are Saying
Hi-Fi Choice reviewed the M6 500i and gave it strong praise, calling it the ultimate amp for many audiophiles. The reviewer highlighted the combination of prodigious power, refined sound quality, and exceptional build as a package that sets a very high bar for integrated amplifiers at any price.
AVForums’ Ed Selley gave the M6 500i an in-depth review, praising the enormous dynamic headroom and the effortless way it handles demanding musical passages. He explained that the 500 watts per channel is about dynamic reserves, not volume, and called the amplifier a genuinely impressive piece of engineering that delivers a smooth, controlled, and authoritative sound.
SoundStage! Hi-Fi reviewed the M6 500i extensively, testing it with multiple speakers including Mirage OMD-28s and MartinLogan electrostatics. The reviewer praised its transparent and revealing character, noting better control, greater transparency, and dimensional extension compared to the reference Krell amplifier it replaced. The conclusion: a powerful, well-built amplifier that makes music sound its best.
Building Your System? Here Are Some Great Companions.
- Speakers — The M6si500 will drive virtually any speaker on the market, from sensitive floorstanders to demanding planar magnetics and electrostatics. Browse speakers.
- DACs (Digital-to-Analog Converters) — Since the M6si500 is a pure analog amplifier with no built-in DAC, pair it with a quality DAC for digital sources. The balanced XLR input is ideal for DACs with XLR outputs. Browse DACs.
- Phono Preamps — For vinyl playback, you will need a separate phono preamp. Browse phono preamps.
- Turntables — Complete your analog chain with a quality turntable. Browse turntables.
- Speaker Cables — The M6si500 supports bi-wiring with four sets of binding posts. Browse speaker cables.
- Interconnect Cables — Use quality RCA or XLR cables between your source and the M6si500. Browse audio cables.
Features & Specifications
Genuine Dual-Mono Design — Separates Performance in One Chassis
The M6si500 is internally configured as a separate preamplifier with two independent monobloc power amplifiers. Each channel has its own transformer and its own heatsink. The preamp has its own independent power supply winding. This architecture delivers outstanding channel separation, a wider stereo image, and a quieter noise floor compared to conventional single-transformer integrated amplifiers.
500 Watts per Channel — Effortless Dynamics at Any Volume
500 watts per channel into 8 ohms (27dBW) is more than most speakers will ever demand. The benefit is not volume — it is dynamic headroom. Music has peaks and transients that require sudden bursts of power. With 500 watts in reserve, the M6si500 handles these moments without compression or strain. The music sounds relaxed, open, and controlled, even during the most demanding passages.
Massive Current Delivery — 12 Bipolar Transistors per Channel
Each channel uses 12 large bipolar output transistors capable of delivering 200 amps peak-to-peak. This is the kind of current delivery that ensures the amplifier maintains complete control of your speakers, regardless of impedance dips or challenging loads. Speakers that other amplifiers struggle with are driven effortlessly by the M6si500.
Precision Digital Volume Control
The volume control uses laser-trimmed substrate resistors for perfect left-right channel tracking at every volume level, including very low listening levels where conventional volume controls often lose balance. This ensures that your stereo image remains precisely centered and detailed, whether you are listening quietly late at night or filling the room.
Ultra-Short Signal Path
The five input sockets are connected directly to the main preamp circuit board instead of using wire connections. This ultra-short signal path ensures minimal impedance and signal degradation from the moment your source enters the amplifier.
Military-Grade Build Quality
The front panel is a bespoke, fine-line extrusion of military-grade aluminum. The heatsinks are custom-made for outstanding heat dissipation and a refined finish. At 30 kg (66 lbs), the M6si500 is built like a vault. This is an amplifier designed to last for decades.
Quick-Reference Specifications
| Amplifier Performance | |
| Power Output (8Ω) | 500 watts per channel (27dBW) |
| Architecture | Dual-mono (separate preamp + two independent monobloc power amps) |
| Output Transistors | 12 bipolar per channel; 200A peak-to-peak |
| THD+N | <0.01% typical (20 Hz – 20 kHz); 0.008% at 1 kHz |
| Signal-to-Noise Ratio | >100 dB (A-weighted) |
| Frequency Response | +0, –0.1 dB (10 Hz – 20 kHz) |
| Connectivity | |
| Line Inputs (RCA) | 4 pairs (CD, Tuner, Aux/HT, Tape) — 1 with home theater bypass |
| Balanced Input (XLR) | 1 pair |
| Pre Out | 1 pair RCA (variable) |
| Fixed Out | 1 pair RCA |
| Speaker Outputs | 4 sets binding posts (2 per channel for bi-wiring) |
| Physical & Power | |
| Dimensions (W × H × D) | 440 × 160 × 460 mm (17.3” × 6.3” × 18.1”) |
| Weight | 30 kg / 66 lbs (unpacked); 35 kg / 77 lbs (packed) |
| Finish | Available in Black or Silver |
| Volume Control | Precision digital with laser-trimmed substrate resistors |
Frequently Asked Questions
Does the M6si500 have a built-in DAC or phono stage?
No. The M6si500 is a pure analog integrated amplifier. It does not include a DAC, phono stage, or headphone amplifier. If you listen to digital sources, you will need a separate DAC or a source component with analog outputs. For vinyl, you will need a separate phono preamp. This keeps the signal path as clean and uncompromised as possible.
Do I really need 500 watts per channel?
Probably not for sheer volume — but the power reserves make an audible difference in sound quality. An amplifier with massive headroom sounds more relaxed, more open, and more dynamic because it is never working hard, even during sudden peaks. Reviewers at AVForums specifically noted that the 500 watts is about dynamic reserves, not volume. Even at moderate listening levels, the M6si500 sounds effortless in a way that lower-powered amps do not.
How does the M6si500 compare to the M6si?
The M6si delivers 220 watts per channel and includes a built-in DAC, USB input, and phono stage — it is a more feature-rich product. The M6si500 strips away those extras and focuses entirely on analog amplification, delivering more than twice the power in a dual-mono architecture with separate transformers per channel. If you already have a separate DAC and phono preamp and want the best possible amplification, the M6si500 is the more focused choice.
Can I use the M6si500 in a home theater system?
Yes. The Aux/HT input functions as a home theater bypass. Connect the front left and right pre-outs from your surround processor to this input, and the M6si500 acts as a power amplifier for your front channels while your processor handles the volume. For two-channel music, switch to any other input and the M6si500 takes over as a full preamp/amp.
Is it heavy? Do I need a special rack?
Yes, the M6si500 weighs 30 kg (66 lbs). You will need a sturdy rack, shelf, or equipment stand that can support this weight. We recommend having a second person help with unpacking and placement. Make sure there is adequate ventilation around the heatsinks on both sides.
Can I bi-wire my speakers?
Yes. The M6si500 has four sets of speaker binding posts — two per channel — so you can bi-wire compatible speakers. If your speakers do not support bi-wiring, simply use one pair of binding posts per channel.
Does the remote control power on and off?
The remote handles input selection, volume, and mute. Power on/off is controlled by the front panel switch. Check with Musical Fidelity for the latest details on remote functionality.
What speakers pair well with the M6si500?
The M6si500 will drive virtually any speaker on the market. It is an especially good match for speakers that are hard to drive — low impedance designs, planar magnetics, electrostatics, or large floorstanding speakers with complex crossovers. AVForums users have reported excellent results with Tannoy, Focal, B&W, and other demanding speakers. Give us a call at 800-942-0220 and we will help you find the right match.
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