NuPrime STA-9X Power Amplifier - Silver

NuPrime STA-9X: Compact Class A+D Stereo Power Amplifier

The STA-9X is a stereo power amplifier rated 2 x 130 watts, and it bridges into a 330-watt mono amplifier. This listing is the Silver finish.

NuPrime designed it to capture the appealing traits of tube and Class A sound without their drawbacks. Its frequency response reaches 50 kHz.

Class A Front End, Class D Power

A single-ended, non-negative feedback Class A preamp stage feeds a dual-feedback Class D power stage. The design comes from NuPrime's AMG STA. NuPrime says it gives more detail and resolution than the original STA-9.

750 kHz Switching and Even-Order Harmonics

The Class D stage uses a self-oscillating circuit that switches at 750 kHz. NuPrime notes most Class D amps switch at 300 kHz or lower. Enhanced even-order (H2) harmonic circuitry adds warmth and a natural character.

Linear Power Supply and More Current

A linear power supply with a high-efficiency toroidal transformer lowers high-frequency noise and strengthens bass. Output current is 130% higher than the STA-9, helping low-impedance speakers. NuPrime's isolation feet damp vibration.

How the STA-9X Fits Your System

The STA-9X is a power amplifier only. It has no volume control or source selection, so it needs a preamplifier or a DAC with volume control in front of it.

It has one balanced XLR input and one RCA input. NuPrime says not to connect both at once; a toggle switch selects which one is active. A 12V trigger lets it power on with your preamp.

Who Is This Power Amplifier Best For?

• Separates builders — pair it with a preamp or a DAC with volume control.
• Space-limited racks — it is just 55 mm tall and 235 mm wide.
• Upgraders — bridge a second STA-9X later for 330W mono per channel.
• Low-impedance speakers — it has 130% more current drive than the STA-9.
• Not for — anyone wanting a single box with volume control and inputs; choose an integrated amplifier.

How Does It Connect to Your System?

• Connect your preamp or DAC to the XLR or RCA input, and set the toggle switch to match.
• Connect speakers to the stereo speaker outputs, or to the mono output when bridged.
• Link the 12V trigger to your preamp if it has one.
• Check the voltage select switch matches your mains (115 or 230 VAC).
• Available in Black or Silver; this listing is Silver.

Pairs Well With

Build a separates system around the STA-9X:

• Preamplifiers
• Digital to Analog Converters
• Interconnect Cables
• Speaker Cables

Frequently Asked Questions

Does the STA-9X have a volume control?

No. It is a power amplifier, so use a preamplifier or a DAC with volume control in front of it.

Can I use it as a mono amplifier?

Yes. It bridges into a 330-watt mono amplifier. Two units in mono drive a stereo pair of speakers.

Can I connect XLR and RCA at the same time?

No. NuPrime says not to connect both. Use the toggle switch to pick XLR or RCA.

How is it different from the STA-9?

The STA-9X adds the AMG STA-derived Class A/Class D design, a new linear power supply and 130% more output current.

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