NuPrime STA-9

NuPrime STA-9 is based on ULCAM (Ultra Linear Class A Module) + the Class D design first introduced in the IDA-8. By combining a powerful high-impedance single-ended amplifier circuit in the preamplifier stage with a well-integrated Class D power stage, the STA-9 delivers a rich, tube-like sound with the remarkable speed and clarity of NuPrime's Class D design. Audio enthusiasts are sure to be impressed.

The NuPrime amplifier circuit improves the traditional Class D design by using a self-oscillating circuit to generate pulse-width modulation. The amplifier switches at a frequency of 550 kHz, far beyond the CD sampling frequency of 44.1 kHz. Most Class D amplifiers switch at 300 kHz or lower. The ensemble is complemented by NuPrime's new linear power supply with a high-efficiency toroidal transformer for reduced high-frequency noise and enhanced low-frequency performance. The damping effect from NuPrime isolation feet absorbs and eliminates vibrations that degrade sound performance. The result is an unmatched transient speed and an almost shocking level of dynamic impact. STA-9's frequency response up to 50 kHz elevates vocals to an emotional experience; likewise, the upper registers of instruments mimic the shimmering heights of a live performance.

Features:

• Single End Class A + D amplifier design
• Bridgeable to switch between stereo mode and mono mode
  
• Highly reliable under unloaded conditions and improved short-circuit protection
• High output current capacity for low-impedance speakers
• 550 kHz switching frequency for precise reproduction of the music signal
• New linear power supply with a high-efficiency toroidal transformer. Reduced high-frequency noise and enhanced low-frequency performance
• The signal path avoids cross-coupled capacitors, providing a frequency response at DC level for pure musical enjoyment

How did STA-9 mono achieve better sound characteristics, beyond more power than STA-9 stereo?

The standard method for bridging a stereo amplifier to mono uses a series of operational amplifiers (OPA) to invert the input signals to one of the stereo amplifiers, creating an opposite phase that can then be combined to increase power. However, STA-9's innovative bridge circuit uses a design NuPrime calls Single-Ended Direct-Inject Bridge Technology, where the mono mode, besides delivering more than double the power, sounds livelier and more dynamic.

NuPrime sound

• Large soundstage
• Lightning-fast dynamics
• Ultra-low distortion and noise
• Music emerges from an untouched background, with delicate details and intact nuances

In summary, NuPrime's sound character stands distinctly apart from – and indeed above – the soft, fluffy sound we often associate with most tube amplifiers or the dry, clinically sharp sound we often associate with solid-state and switching technology. Rarely does an amplifier achieve an ideal balance of richly textured tones and harmonies, authority in the bass register, astonishing dynamics, exquisite low-level detail, and a fully revealed, multidimensional soundstage against a background of deep silence.

• Inputs:
  • RCA: Unbalanced input x 1
  • XLR: Balanced input x 1
• Outputs:
  • Stereo speaker output x 1 or
  • Mono speaker output x 1
• Power: 2 x 120 W / 1 x 290 W at 8 and 4 ohms
• Maximum output power: 2 x 280 W / 1 x 320 W at 8 and 4 ohms
• Input impedance: 47k ohms
• Input sensitivity: 232.8 mV, 1 W at 8 ohms; 1.4 V to nominal power
• Gain: x 22 (x 42 for mono)
• Signal-to-noise ratio: < -95dB at 1W, 10W, 100W
• Dynamic range: -115dB to 0dB at 1kHz
• THD+N: 0.02% (stereo) / 0.01% (mono)
• Frequency response: 10Hz to 50kHz
• AC fuse: Slow blow, 3A, 250VAC
• Dimensions: 235 mm W x 281 mm D x 55 mm H (including feet)
• Weight: 4.75 kg
• Color: Black or silver
• In a 230V outlet, the power consumption in standby is under 16W.