High Fidelity Audio Power Amplifier

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I am a proud audiophile.
Audiophile is a person who is especially interested in high-fidelity sound reproduction. High Fidelity means sound reproduction over the full range of audible frequencies (20 Hz to 20 kHz) with very little distortion of the original signal. Audiophile’s amplifier or high fidelity amplifier is a amplifier that reproduces music that sounds identical to the sound on the recorded source. If an amplifier has a frequency response within 1 dB across the audible range, with THD less than 0.1%, power rating larger than 50 W, damping factor larger than 10, then that device can be considered as a high fidelity amplifier and it is audibly transparent. By definition, one audibly transparent device sounds identical to all other such devices playing with the same source material, at the same gain through the same speaker. My audiophile’s amplifier is a high fidelity amplifier, so is McIntosh MXA60 and Marantz PM-10. This means my amplifier; McIntosh MXA60 and Marantz PM-10 all sounded exactly the same.

Why majority of the audiophiles do not buy high fidelity amplifier?

1. Cost: All HI-FI amplifies are expensive. McIntosh MXA60 priced at $7,500 and Marantz PM 10 priced at $7,999. Many other HI-FI amplifiers cost even more. Not all audiophiles are rich, so only a few of us can afford them.
2. Weight: McIntosh MXA60 net weight 64lbs Marantz PM 10 weight 47.4 lbs. This kind of amplifiers can only be used at home not anywhere else.
3. The styling of HI-FI amplifiers is too old fashion for younger generations. McIntosh enclosure with two blue VU meter looks like it was designed 40 years ago; actually it was designed 40 years ago.

Forty years ago we have LP, tapes AM/FM radio go through a preamplifier then to power amplifier. Because preamplifier changes the frequency response curve; any audio system has a preamplifier is no longer a high fidelity system. Today most of the sources are digital, the one that is not digital can be converted into digital. Most of us use iPad (Android) feed the power amplifier through blue tooth without wires. If you like to change the frequency response of the music you can always download an APP to do it.
I had some success to build HI-Fi amplifier before.
About thirty years ago I build a MOSFET complementary, class AB push-pull amplifier and let Marantz test it. The THD of this amplifier measured 0.003% at 20 Hz and 0.06% at 20 kHz. The test was performed at 75 W with 8 Ohm load.

This time I am building a high fidelity amplifier weights merely 9 lbs, housed in a modern looking semi-transparent box and sale for $750 (one tenth of MXA60). This is my contribution to all music lovers that is not a rich man.


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  • Name:
    Kelvin Shih
  • Type of entry:
  • Profession:
  • Number of times previously entering contest:
  • Kelvin is inspired by:
    How expensive a high fidelity amplifier cost.
  • Software used for this entry:
    Circad PCB design
  • Patent status: