Tuesday, March 14, 2017

A HIFI Class B Amplifier Refer to NAP140 Circuit

A HIFI Class B Amplifier Refer to NAP140 Circuit

Power Amplifier of Named Naim is one of those products worshiped by audiophiles like as Linn turntables. Though its unassuming appearance, but it has won the hearts by warm mellow tone. Naim price is not low, people who really know what was the expert are willing to spend money to buy it. If you are truly listening to music, you will feel that once you owned and not much else for this amplifier.

I love this circuit Naim NAP140 as much love for the 1969 circuit. Because it sounds isn’t worse than 1969, and its output power is far better than 1969. One feature of NAP140 amplifier architecture is its mostly second-harmonic distortion, so the tone is somewhat like as tube amplifier charm. But the difference is that it is very rewarding that the distortion of tube amp to achieve 0.1%, but this circuit can be achieved 0.01% distortion.

IWISTAO HIFI Power Amplifier 80Wx2 Stereo NAP140 Mellow Soft Sound Tube Taste Black from IWISTAO HIFI MINIMART1 on Vimeo.

We made this HIFI amplifier to refer to Naim Nap140 designing, and hope in keeping NAP140 original fine circuit architecture as same premise, to use new devices, greatly improve the operating voltage and output power, improve stability, and to Try to do something to improve the circuit (for example, the circuit adapted to work class A state). The original unit is very popular with enthusiasts respected, but also the price of its second-hand is nearly USD 2000. We do not engrave it, and cannot do it, only with reference to its excellent circuit configuration. The amplifier’s circuit is very mature, stable, ultra-low power consumption, driving and control force is very, very good, far better than integrated circuit amplifier or similar circuit at same output power, it is cannot be compared by them. More commendable is that the sound of this Class B circuit is mellow and soft as same as class A one at low power consumption.

Its output power is able to reach 80W at 8 ohms and class B state.


  1. Basically to be faithful to H140 classic circuit.
  2. Add upc1237 speaker protection system, switch absolutely no impact sound while performing midpoint of DC protection, to prevent damaging or burn your expensive speakers due to the amplifier circuit.
  3. Integrate volume control potentiometer.
  4. Integrate a two inputs switch on the front panel, you can switch the input source via the front panel.
  5. Add a midpoint adjustment circuit on differential input, generally midpoint can adjust to 5mV or less.
  6. The finished unit with about 2KG heat sink, while it is whole aluminum design, this benefit other parts of the casing become heat sink also in addition, so that the total heat dissipation area greatly increased. Its actual operating temperature up to 40 degrees, low-carbon green!
  7. Use a special custom 200W HIFI OFC toroidal transformer, ensure enough reserve power!
  8. Use a lot of HIFI elements like as ALPS27 potentiometers, high-grade RCA connect, ELNA capacitors and HIFI chemicals one. Sound’s quality is the most important thing.

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