In a move that’s set to electrify the high-end audio scene, Ultrafide Audio has officially launched the SP500 stereo power amplifier, a sleeker, more accessible evolution of its acclaimed U500DC model. Priced at an enticing £3,990 (including VAT), the SP500—short for “squaredPOWER”—marries professional-grade engineering with domestic elegance, promising the same “power with emotion” that has made Ultrafide a darling among audiophiles and studio pros alike. The amplifier makes its public debut at the 2025 Edinburgh HI-AV Show on November 8-9, where it’ll pair with Kudos 505 speakers for a demo that’s already generating buzz.
Ultrafide, a brand born from the pro-audio pedigree of MC² Audio, has long championed the idea that “pro sound is homebound.” The SP500 embodies this ethos, distilling the raw power and sonic purity of its bigger sibling into a more compact chassis without compromising on performance. Measuring a tidy 590mm (L) x 405mm (W) x 152mm (H) and weighing in at 14.65kg packed, its minimalist straight-edge casework is designed for seamless integration into hi-fi racks, mixed systems, or even studio setups—thanks to optional rack-mount compatibility.
At its core lies Ultrafide’s proprietary Ultra Sigma output topology, first unveiled in the U500DC, which delivers breathtaking transparency and musical engagement. DC-coupled from input to output, the SP500 ensures signal integrity with zero phase shift, resulting in a “PURE timbre sonic signature” that’s both neutral and emotionally resonant.
Mark Bailey, product specialist at Ultrafide Audio and MC², couldn’t hide his enthusiasm: The SP500 is everything that’s loved about our U500DC Ultra Sigma amplifier, but with a more minimal approach to its casing that we really like and have been asked for on numerous occasions. We’ve added the additional ability to rack mount, and made some clear I/O connection differences to make it even more flexible and applicable to CI, studio, cinema markets, as well as traditional Hi-Fi. The internals of the SP500 are almost identical to that of the U500DC, with just a subtle change to input/output circuitry, so the performance is equally breathtaking.
Flexibility is key here. The SP500 offers four audio inputs—two RCA (single-ended) and two XLR (balanced)—all active simultaneously, allowing users to sum sources for creative mixing if desired. Outputs include two pairs of binding posts and NL4 speakON connectors, catering to both home enthusiasts and install pros. Input impedance sits at a forgiving 10k ohms across both types, with RFI filtering capacitance at 550pF to keep noise at bay.
Power delivery is where the SP500 truly shines, living up to its “squaredPOWER” moniker. It pumps out a robust 500W RMS into 4 ohms (600W at the optional high-gain setting), scaling gracefully to 333W into 6 ohms, 250W into 8 ohms, and 166W into 12 ohms. Stable down to 2-ohm loads, it handles demanding speakers with ease, backed by a maximum voltage of 70V and pulsed current up to 30A. Voltage gain defaults to 26dB (switchable to 29dB), with a sensitivity of 2.2V and an impressive 115dB dynamic range (unweighted, 22-22kHz). Distortion is vanishingly low at 0.003% at 5W, and the frequency response holds ±0.3dB from 5Hz to 20kHz. A swift 10µs rise/fall time and unconditional stability round out the technical prowess.
Practical touches abound: A 10A Furutech C13 IEC power inlet supports 230Vac (50Hz) or 120Vac (60Hz) via an internal selector, with fuses and switches for safety. Power draw averages 200W in operation (up to 1,000W max), idles at 15W, and sips just 1W in standby. Front-panel standby and rear remote options make it user-friendly, while green and red LEDs signal status and faults like clipping.
For those attending the Edinburgh HI-AV Show, Room [TBD] will host this compact yet formidable setup, showcasing how the SP500 elevates any system with its warm, detailed sound. As Bailey teases, “We can’t wait to formally unveil the SP500… and will have more exciting news within the region coming soon.”
