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Fosi audio TPA3116 BT20A


Jul 16, 2021
I tried the amplifier with two purposely built studio speakers and reproducing acoustic recordings manly of serious music, with power outputs lower than 20 W RMS. The overall harmonic distortion was lower than 0,5 % as claimed by Fosi, which enabled a pleasant reproduction of the stringed instruments. The intermodulation distortion (IMD), which confuses the sound of multiple sources, was more noticeable, especially with ensembles of chords or human voice choruses and this was to be expected since the class D amplifier chops the audio signal. Actually the IMD is present in most of the commercial speakers which do not have treated surfaces inside, making it more difficult to distinguish the amount attributable to the amplifier from that produced by the speaker.
To appreciate the frequency response it was necessary to set the tone controls with the knobs pointing around 3 o'clock and was mostly flat, falling noticeably only at very low frequencies, under 40 Hz. The reproduction of pipe organ music was quite acceptable, even for the 32 feet registers.
The signal to noise ratio of about 70 dB is a value we would like to recommend the manufacturer to work on.
The operation of the relay commute, between audio and Bluetooth inputs is silent and effective. The useful Bluetooth range is more than 5 meters. The quality of the Bluetooth 4,2 audio is adequate for a second input.
So, the 5 stars over 5 go taking in consideration this is a class D amplifier.


Active Member
Mar 26, 2020
pretty much just posted this on another fosi thread

the A04 and A07 would be an upgrade over the 3116 chip at the exact same price point

granted they dont have tone control or BT, but they do have models that do if that is required and EQ wouldnt be able to be handled upstream
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