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Mimics the Most Attractive Features of Tubed and Class-A Amp Sound
The NuPrime STA-9X is a 2 X 130W Class A+D stereo amp, bridgeable into a 330W mono amp. It's designed with enhanced even-order harmonic circuitry that mimics the most attractive features of tubed and Class-A amp sound without incurring their drawbacks and limitations. The STA-9X’s frequency response to 50 kHz elevates vocals into emotional experiences, while instrumental upper registers mimic a live performance’s shimmering heights.
The STA-9X amplifier improves upon the ULCAM (Ultra Linear Class A Module)+Class D design of the STA-9 with a design concept taken from the high-end NuPrime AMG-STA amplifier. By joining a robust high impedance singled-ended non-negative feedback amplifier circuit in the preamp stage with a dual feedback Class-D power stage, the STA-9X sounds warm and dynamic with remarkable speed and clarity. This NuPrime amplifier improves upon the traditional Class-D switching design by using a self-oscillating circuit to generate pulse-width modulation. STA-9X switches at a frequency of 750kHz (highest on the market), well beyond the compact disc’s 44.1kHz sampling rate. Most class-D amps switch at 300kHz or lower.
The 130% higher output current drive capability than the STA-9 allows low impedance speakers to have better dynamic and power with the STA-9X. Plus, it is highly reliable under no-load condition and features enhanced short circuit protection.
An Almost Shocking Level of Dynamic Impact
Completing the upgrades is NuPrime’s new linear power supply with its high-efficiency toroidal transformer for reduced high-frequency noise and strengthened low-frequency performance. The signal path avoids cross-linking capacitors, thus achieving a frequency response at the DC level for pure musical enjoyment. The damping effect of the NuPrime proprietary isolation feet absorbs and cancels vibrations that degrade audio performance. The result of all this advanced technology is unprecedented transient speed and an almost shocking level of dynamic impact.
In summary, the sonic character of the STA-9X stands well apart from – and indeed above – the soft, cushy sound we often associate with most tubed amplification or the dry, clinically edgy sound associated with solid-state and switching technology.
Enhanced even-order harmonic (H2) circuitry creates warmth and natural sound characteristic. According to NuPrime, "Rarely does an amp achieve an ideal balance of richly textured timbres and harmonics, bottom-end authority, startling dynamics, exquisite low-level detail, and a fully revealed, fully dimensional soundstage against a backdrop of mile-deep silence."
