This is a review and detailed measurements of the Fosi Audio TB10D stereo amplifier. It was sent to me by the company and is only sale for US $70 on Amazon including shipping.
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We have the typical compact desktop aluminum case. Controls feel nice for the class. Tone controls are not centered however for flat response (you can see in the picture what I set them to). Typical of these budget amplifiers, power is provided externally through a switching supply:
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Binding posts are spaced out a bit more which made it easier for me to plug in my large cables.
This is a class D amplifier based on TI TPA3255 single chip amplifier.
Fosi Audio TB10D Measurements
Let's start with our usual 5 watts measurement of 1 kHz tone into 4 ohm load:
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Dominant distortion is third harmonic which essentially sets SINAD to same level. This is slightly below average but considering the price of this amp, it is reasonable:
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Kind of interesting that the $5,900
Jeff Rowland 535 amplifier lands almost next to it!
Signal to noise ratio is modest but again, good for the class:
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Crosstalk holds its own against much more expensive amplifiers:
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Frequency response is variable due to bass and treble control and load dependency:
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The load dependency is the norm in this class. Hopefully some amp comes along and with no cost penalty takes care of that (by incorporating the output filter into the feedback loop).
Distortion rises with frequency which we can see in multitone test:
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Power is everything in amplifiers so let's see how much we have:
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This is quite healthy for such a small and low cost amplifier! It gets even better if we allow 1% distortion:
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We are talking essentially 200 watts coming out of this little box! Cost per watt is just 35 cents. Amazing.
Even with 8 ohm load we get good amount of juice:
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Amplifier "transfer function" (output vs input) is very good for class D although it does show rise in distortion as noted earlier:
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Of note, you still have 66 watts of power at 20 Hz. Many budget amps drop to 20 or so watts which can be problem as bass is what requires power.
Conclusions
Maybe one day this will change for for now, in under $100 range you can't expect perfection in performance of a stereo amplifier. What you do want to see is delivering healthy amount of power with close to our average of all of our amplifiers tested to date. On that front, the Fosi Audio TB10D delivers. If you need an amplifier for secondary use (bedroom, workshop, etc.), the TB10D is a very good candidate for no more money than one or two dinners!
I am going to recommend the Fosi Audio TB10D amplifier.
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