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.
View attachment 233507
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:
View attachment 233509
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:
View attachment 233510
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:
View attachment 233511
View attachment 233512
Kind of interesting that the $5,900 Jeff Rowland 535 amplifie
r lands almost next to it!
Signal to noise ratio is modest but again, good for the class:
View attachment 233513
Crosstalk holds its own against much more expensive amplifiers:
View attachment 233514
Frequency response is variable due to bass and treble control and load dependency:
View attachment 233515
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:
View attachment 233516
Power is everything in amplifiers so let's see how much we have:
View attachment 233517
This is quite healthy for such a small and low cost amplifier! It gets even better if we allow 1% distortion:
View attachment 233518
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:
View attachment 233520
Amplifier "transfer function" (output vs input) is very good for class D although it does show rise in distortion as noted earlier:
View attachment 233521
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.
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.
As always, questions, comments, recommendations, etc. are welcome.
are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/