Introduction to the HPA-nxV300 R2 amplifier module.

The nxV300 R2 audio amplifier module is based on the high performance nxV500 R2 module. Unlike the nxV500 which has eight Toshiba output devices this version has four high performance Toshiba MOSFET's in it's output stage. Making it a much more compact but no less powerful. Boasting a power output of around 220 watts RMS into 8 Ohms and 380 watts RMS into 4 Ohms.

It also has XLR Balanced input which can be easily configured for RCA or unbalanced input.

The sound quality is in the same league as the very popular nxV200 and the nxV500 modules, making it an ideal companion to the nxVxxx range of amplifiers.

The HPA-nxV300 R2modules comes fitted with Nichicon audio grade capacitors and are also supplied with the output stage silicon insulation washers.

The Printed Circuit Board is a double sided plated through hole and SMD extra heavy duty 3 ounce copper foil with Gold emersion plating and the layout includes a low noise ground plane on the underside of the PCB.

Like all of the R2 modules in the nxV range it has the capability of using separate power supplies for the input and drivers stages.


Here is what do you need to build a stereo HPA-nxV300 R2 Amplifier.

For the not so budget minded.

  • Two HPA-nxV300 R2 Amplifier modules.
  • Two HPA-NXVPSU-One power supply boards.
  • One HPA-Limiter-1 Mains surge limiter.
  • Two HPA-LSP-1 Loudspeaker protection boards.
  • One HPA-Chassis-One.
  • One 625VA Torodial transformer with 50vac +50vac secondary windings.
  • One pair of ETI Eichmann Phono Pods.
  • One pair of ETI Eichmann Cable Pods.
  • High quality OFC copper hookup cable
  • One high quality IEC mains chassis socket with built in fuseholder.

For the more budget minded.

  • Two HPA-nxV300 R2 Amplifier modules.
  • One HPA-Limiter-1 Mains surge limiter.
  • One 500VA Torodial transformer with 50vac +50vac secondary windings.
  • MF30-75 heat sinks per channel
  • Your own chassis of choice.
  • Your own handwired power supply of choice.
  • Your own cable and mounting hardware and IEC chassis socket of choice .


HPA-nxV300 module mounted to the HPA-NXVPSU-One power supply board.

Stereo HPA-nxV300 Amplifier in the making!

  • Featuring Balanced XLR and Single Ended RCA input stage.
  • Very low Noise and Distortion
  • Unconditionally Stable
  • Extra Heavy Duty three ounce copper printed circuit boards.
  • Gold emersion copper track plating
  • Rugged high performance Toshiba MOSFET output stage.
  • RoHs Compliant

Preliminary Specifications

  • 220 Watts RMS continuous sine wave into 8
  • 380 Watts RMS continuous sine wave into 4
  • The HPA-nxV300 R2 is 2 Ω Stable
  • Biased into Class A/B
  • Power Bandwidth 3.5hz to 550khz -3dB
  • Slew Rate = 85v / microsec approximately
  • Dampening Factor At 100hz  8Ω = 900
  • Dampening Factor At 1khz    8Ω = 750
  • Dampening Factor At 10khz  8Ω = 250 
  • RCA Single ended Input impedance 20k
  • XLR Balanced Input Impedance 40kΩ
  • Differential Input Gain = 33.8dB
  • Single Ended Input Gain = 28.1dB
  • Recommended Linear Voltage Supply +-70 volts DC
  • Operational Supply Voltage Range +-10v dc to +-95 volts dc
  • PSU Power Transformer secondary windings 50vac (500VA)
  • Printed Circuit Board Dimensions 110mm x 50mm
  • Recommended Conrad Heat Sink MF30-75


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