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Masterclass FPA-4 Power Amplifier (Production ended 2019)

The FPA-4 power amplifier is the latest member of the Sugden Masterclass Family. This output stage is of the classic Sugden pure class A single ended voltage rail design which has given musical satisfaction to thousands of discerning music lovers over many years. The amplifier benefits from a comparator and correction circuit so that errors which would occur in the power stage, due to varying loads and distortion, are corrected to match the output of the high impedance input amplifier. Whilst it is maintaining the signal authenticity it is also increasing the load stability and forces the output impedance to zero. The Amplifier with Sugden Error Correction has extremely low open loop output impedance with a resultant high damping factor at quite high frequencies.

Coupling of the output of the Amplifier to its chosen speakers is via a ‘soft connection’ protection board. It is a static contact switching board using extremely low ‘on resistance’ power mosfets. These devices are timed on and off to enable soundless connection to the speakers however sensitive.  The FPA-4 is an exciting new design that performs well above its modest price point.

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Inputs ​                                    Stereo line level, stereo balanced

Outputs                                  Stereo pair multi-way locking binding posts



Input Sensitivity                      1Volt for full output

Power Output                        25 Watts per channel both channels working

Frequency Response           -0.3dB 18Hz-95kHz

Bandwidth                             10Hz-125kHz

Signal to Noise                      >82dB

Distortion at 1 Watt 1kHz      <0.04%

Gross Weight  (packed)       15kgs

Dimensions                           143 x 430 x 350mm (hwd)




J E Sugden & Co Ltd, Heckmondwike, West Yorkshire.

The manufacturer reserves the right to change specifications without notice.

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