NAD PP4

The NAD PP4 is a digital phono preamplifier that combines an optimized analog circuit with digital conversion. It is designed to allow turntables to connect to modern audio systems, ensuring amplification and conversion tailored to the phono signal.

A Sophisticated Circuit in a Minimalist Format

The PP4 features an electronic architecture that prioritizes signal quality without unnecessary embellishments. Its compact chassis, measuring 135 mm wide, just 49 mm high, and 72 mm deep, conceals a refined electronic design. The graphite case, weighing barely 500 grams, houses a circuit that combines discrete transistors and operational amplifiers selected for their audio characteristics.

The input stage for moving coil (MC) cartridges uses four transistors in a differential configuration, specifically optimized to handle the particularly low impedances of these cartridges. This discrete transistor section then feeds a RIAA stage based on operational amplifiers, where metal film resistors and film capacitors ensure signal accuracy across the entire audio spectrum. The external 24-volt power supply, increased from the 15 volts of previous generations, improves headroom and musical dynamics.

An integrated subsonic filter attenuates unwanted frequencies with remarkable efficiency: -14 dB at 5 Hz and -3 dB at 10 Hz. This technical feature, often overlooked in entry-level preamps, protects your amplifiers and speakers from low-frequency oscillations generated by record irregularities or mechanical vibrations from the turntable.

Cartridge Matching: Calculated Versatility

The PP4 accommodates both moving magnet (MM) and moving coil (MC) cartridges with equal ease, thanks to distinct and optimized input circuits. For MM cartridges, the 47 kΩ input impedance combined with 200 pF capacitance is the industry standard, ensuring compatibility with almost all cartridges on the market. The 35 dB gain and 5 mV sensitivity to achieve 200 mV output meet the typical needs of these transducers.

MC cartridges receive special treatment with a 100 kΩ input impedance and 180 pF, a substantial 58 dB gain, and an impressive 0.38 mV sensitivity. These technical values reflect the PP4’s ability to extract the delicate signal from high-end MC cartridges, known for their low output but superior resolution.

The accuracy of the RIAA curve, maintained at ±0.3 dB between 50 Hz and 20 kHz, demonstrates the care taken to faithfully reproduce the original recording. This precision in applying the de-emphasis curve ensures that bass regains its natural fullness and treble retains its balance, exactly as intended during the record’s mastering.

USB Digital Phono Preamplifier

• Built-in subsonic filter
• High-quality analog-to-digital conversion
• VinylStudio Lite software included

Specifications

• Input impedance
  • 47 kΩ + 200 pF (MM)
  • 100 kΩ + 180 pF (MC)
• Gain:
  • 35 dB (MM)
  • 58 dB (MC)
• Input sensitivity for 200 mV output
  • 5 mV (MM)
  • 0.38 mV (MC)
• Total harmonic distortion < 0.03% (20 Hz - 20 kHz)
• Signal-to-noise ratio
  • 76 dB (MM)
  • 78 dB (MC)
• Subsonic filter
  • -14 dB (5 Hz)
  • -3 dB (10 Hz)
• Dynamic range
  • 89 dB (MM)
  • 86 dB (MC)
• RIAA curve accuracy ±0.3 dB
• USB sampling PCM 48 kHz/16 bits
• Sampling frequency 48 kHz

Connectivity

• MM and MC type inputs
• Stereo audio input
• Input selector
• Stereo audio output
• USB port and Plug’n’Play installation

General

• External 24 V power supply
• Dimensions (W x H x D): 135 x 49 x 72 mm
• Weight: 500 g