EPM-5. Class A Power Amplifier NFB.


We present a Pure Class A Power Amplifier without Feedback.

This is a non-feedback amplifier ideal for use in recording studios with near-field listening and for high efficiency loudspeakers. By not having feedback, the result is an amp that has a little more harmonic distortion, but also avoids the subjective artifacts that come with feedback.

They have only one gain stage and operate in pure Class A mode, which is the best mode, but at the cost of clipping approximately 10 times their rated output.

For this design, two medical grade switching power supplies have been used, one for each channel, achieving greater channel separation. Very low tolerance resistors and Nichicon audiophile grade capacitors have also been used.

This is the distortion graph for a 1W output over an 8 Ohms load.





We can internally insert a cut-off filter at a certain frequency in order to attack a two- or three-way system with high-efficiency loudspeakers.

It is handcrafted in a lightweight, medium-sized aluminum case.

Technical Specifications
(measures at 230 VAC with a 8 Ω load)


  • Input impedance: 50 kΩ
  • Input sensitivity: 1.5 V (RMS)
  • Output power: 1 W @ 0,89% THD, 5 W @ 6,5% THD, 1 kHz, 8Ω
  • Frequency response: 3 Hz – 200 kHz (–1 dB)
  • Gain: 15.6 dB
  • Power consumption: 150 W
  • Fuse: Slow 2 A (230 VAC)
  • Dimensions (W x D x H): 360 x 260 x 90 mm
  • Weight: 3 Kg
  • Warranty: 3 years
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