Nuprime STA-9 Power Amplifier
Features:
Single End Class A + D amplifier design
Bridgeable allowing switch between stereo or mono mode.
Enhanced even-order harmonic (H2) circuitry resembling the most attractive features of tubed-amp sound without its drawbacks and limitations.
Highly reliable under no-load condition and enhanced short circuit protection.
High output current drive capability for low impedance speakers.
550 KHz switching frequency for accurate reproduction of musical signal.
New linear power supply with a high-efficiency toroidal transformer. 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.
How did STA-9 achieve tubed-amp sound?
The front-end circuit of the STA-9 employs the same structure as that of the HPA-9: a single-end JFET structure that mainly simulates the sound characteristics of a triode by the addition of 2nd harmonics. The 2nd harmonic of a vacuum tube and STA-9 are high, resulting in an SNR measured value > 90DB. This does not mean that the STA-9 produces audible noise; rather, it is the effect of 2nd harmonic’s appealing coloration. The bandwidth of the front-end circuits of the STA-9 and HPA-9 are up to 300KHZ, which produce a more natural sound. With very low negative feedback, the sound is smooth and relaxed rather than harsh.