NuPrime STA-9 Power Amplifier

2019, 2022 Editors’ Choice Award - The Absolute Sound

Near Reference Quality at an Entry Level Price

The NuPrime STA-9 is a 2 X 120-watt Class A+D stereo amp that's bridgeable into a 290-watt mono amp. It's designed with enhanced even-order harmonic circuitry that mimics the most attractive features of tube amp sound without the drawbacks and limitations that tube gear is often prone to.

The STA-9 won an Editors' Choice Award from The Absolute Sound magazine, which noted, "Producing 120wpc and weighing just under 10.5 pounds, the STA-9 uses a Class A input circuit along with a Class D output circuit… In monoblock mode, the STA-9 produced powerful bass, even with small KEF speakers."

The compact footprint and stereo/mono amp design makes the STA-9 a very versatile performer. It offers near reference class sound quality at an entry level price.

Pure Musical Enjoyment

The STA-9 is highly reliable under no-load condition and features enhanced short circuit protection. It isn't fussy about your choice of loudspeakers. It provides high output current drive capability for low impedance speakers as well as a 600 kHz switching frequency for accurate reproduction of the musical signal. The signal path avoids cross-linking capacitors, thus achieving a frequency response at DC level for pure musical enjoyment.

A new linear power supply incorporates a high efficiency toroidal transformer. Benefits of this transformer are reduced high frequency noise and strengthened low frequency performance.

Connections consist of one stereo pair of RCA unbalanced inputs and one stereo pair of XLR balanced input, plus stereo speaker out and mono speaker out.

Overview

• Single End Class A + D amplifier design
• Bridgeable allowing switch between stereo or mono mode
• Enhanced even-order harmonic (H2) circuitry delivers the most attractive features of tubed-amp sound without its drawbacks and limitations
• Highly reliable under no-load condition and features enhanced short circuit protection
• High output current drive capability for low impedance speakers
• 600 KHz switching frequency for accurate reproduction of musical signal
• New linear power supply with a high-efficiency toroidal transformer – offering reduced high-frequency noise and strengthened low-frequency performance
• Signal path avoids cross-linking capacitors, thus achieving a frequency response at DC level for pure musical enjoyment
• Color: Black or silver

• Inputs: RCA unbalanced input x 1, XLR balanced input x 1
• Outputs: Stereo speaker out x 1, mono speaker out x 1

• Power: 2 X 120W at 8 & 4 Ohms / 1 X 290W @ 8 ohm and 4 Ohms
• Peak Output Power: 2 X 280W / 1 X 320W @ 8 Ohms and 4 Ohms
• Input Impedance: 47k Ohms
• Gain: x 22
• Signal to Noise Ratio: < -80dB at 1W, 10W, 100W
• THD+N: 0.02% (Stereo) / 0.01% (Mono)
• Frequency Response: 10Hz to 50kHz
• Worldwide AC voltage: (115 VAC / 230 VAC) with Voltage Select Switch
• AC Fuse: Slow-blow, 3A, 250VAC
• Dimension: 9.25" W x 2.2" H (including feet) x 11" D
• Weight: 10.5 lbs.

2019, 2022 Editors’ Choice Award - The Absolute Sound

"Producing 120wpc and weighing just under 10.5 pounds, the STA-9 uses a Class A input circuit along with a Class D output circuit… In monoblock mode, the STA-9 produced powerful bass, even with small KEF speakers."

- The Absolute Sound magazine, March 2019

"These little fellows offer richly textured sound with an excellent soundstage and deep low-end extension, all in a tiny package. The amps build on the classic NuForce Reference models of yesteryear, but take on a subtly relaxed flavor where those older models could be a bit high strung. This is a hugely crowd-pleasing product worthy of serious attention despite its affordable nature."

- Part-Time Audiophile, August 2016