Fosi Audio TB10D 2 Channel Stereo Amplifier, Class D Mini Power Integrated Amplifiers 600W for Passive Speakers/Bass Shaker, Home Audio Component Desktop Amp Receiver TPA3255 with Bass Treble Control

If you are considering purchasing a stereo Class D amplifier and you don't require Bluetooth, digital inputs or balanced inputs then the Fosi Audio TB10D is a great choice. The TB10D stereo amplifier, when paired with a small music streaming device such as one of the WiiM music streamers (also available on Amazon), becomes half of a shoebox sized streaming audio system. You would just need to add a pair of passive (non-amplified) speakers. The bass frequency response of the TB10D was noticeably absent when first powered on. After about a half hour of operation the bass finally showed up and all was good. I leave the TB10D powered on as the standby power draw is very low. [Update: I measured the standby power consumption of the TB10D. Plugged in, not switched on, 1.0 Watt. Switched on, no input signal, power consumption is 2.5 Watts.] Even though I know that the location of the bass and treble tone controls on the TB10D are reversed, as compared with most other amplifiers and receivers with the treble control being on the left and the bass control on the right, I routinely forget and grab the wrong tone control. The speaker binding posts are small and close together. This is not an issue as I use banana plugs when connecting the speaker wires to the TB10D. Note that there is no headphone connection on the TB10D for wired headphones. If you need a small, inexpensive good sounding headphone amplifier for wired headphones consider the Fosi Audio P2 headphone amplifier.The TB10D's available output power, ~50 Watts per channel when used with 8 ohm speakers, with the included 32V/5A power brick is adequate for use in my kitchen audio system. The case and power supply of the TB10D remained cool to the touch even after extended listening (I measured 72F). If you have a large room, lower efficiency speakers, or desire audio levels exceeding ~85dB you should consider a more powerful amplifier. You can change the supplied external power supply for one rated for 48V, however this will increase the overall cost as well as increase the operating temperature of the TB10D. Within its limitations as far as output power, input options (one pair of RCA connections, no digital inputs, no balanced inputs), outputs (one pair of stereo speakers), no Mono mode switch, no BT, no headphone connection or remote control, the Fosi Audio TB10D is a very good choice. I found the sound of the TB10D when powering 4 ohm, 6 ohm and 8 ohm speakers to be consistently smooth, full sounding and non-fatiguing with a variety of music even after prolonged listening.I assembled a complete 2-channel audio system of exceptional value that can fit in a shoe box. Each of these products is currently available on Amazon. I chose the Fosi Audio TB10D amplifier that is the subject of this review. I added the well reviewed, amazingly compact WiiM Mini music streamer. I chose a pair of desktop passive bookshelf speakers. This system is capable of filling almost any size room in a home with great sounding music. The TB10D amplifier's tone controls and the WiiM Home app's equalizer settings can be used to adjust the bass/midrange/treble output of the speakers.

This is a sweet little amp which fits in nicely on computer desk. The sound is excellent. I gave it five stars because it is really good.However, there are a few things that I'd like to mention. First of all, the listing says that the amp can deliver "300W PER CHANNEL POWER: With the high-performance TPA3255 chip, the TB10D 2 channel amplifier delivers 600W of power." That is the specification of the TPA3255 chip, but not what the Fosi TB10D can do! When you look at the power supply, it says 32V, 5.0A, 160W! As you can see in the attached Figure 7 from the data sheet, the maximum output power with a 32V supply at 4 Ohm is 130W and at 8 Ohm it's only 70W! Stating 300W per channel for this particular amp is definitely an exaggeration.The only other critique I have is the power on LED. You can barely see the LED when you look straight at the amp. When you look at the amp at an angle from above, it disappears! I often forget to turn the amp off because I can't see the LED from where I sit. See the attached images.

This amp is small but mighty! The design is very simple which I like! You have two simple bass and treble knobs to tweak the sound, and one toggle power switch on the front. It stays cool even after long use. It’s made from sturdy metal and looks sleek on a desk or shelf. While it claims 300W per channel, real-world performance is more like 45–70W, which is still plenty for most speakers.There’s no Bluetooth or remote, and it only has one RCA input, but for the price, it’s hard to beat.

As a matter of background info, when these inexpensive Chinese-made Class D amps first started appearing, their sound characteristics were almost universally described as being thin, cold (in many cases, harsh in the upper frequencies), and fatiguing for long-term listening. But at the time, they were what they were, and they were selling like hot cakes due to their ridiculously low prices.As time went on, individual brands started producing models that slowly began improving - meaning, warmer with a fuller sound signature. Yet in the end, these models were still lacking in a number of areas.Fast-forward to now. We now have a wealth of updated class D models (most under $100 USD) that have begun to turn heads in a most positive way. The inexpensive class D sound has gradually experienced a metamorphosis - that is, audio reproduction now began to gradually take on a warmer overall tonality with a better overall balance. In addition, some of the newer releases began incorporating welcomed additions such as having removable/changeable Op-Amps - thus allowing the end users to improve the sound to their liking. Upgrading these Op-Amps, in particular, to the discrete, more expensive types (made by MUSES, Sparkos Labs, Burson, etc.), result in significant improvements to audio reproduction. Some of FOSI Audio's later releases such as the BT20A Pro and the wonderful V3, all feature removable/interchangeable Op-Amp capabilities and if you replaced the typical stock NE5532 Op-Amps with either the likes of the MUSES02, BURSON V5i or the Sparkos Labs SS3602 discrete versions, the sound qualities of those amps were advanced substantially.I've owned/used 20 different Asian-made Class D amp over the past years, and when I received this new updated version of the Fosi Audio TB10D, I immediately discovered that it has a sound signature similar to many of the models out there with the Texas Instruments TPA3255 amplifier chip - that is dynamic and a bit warmer and fuller. Like select models using this TPA3255 chip, the user has the ability to use power supplies ranging from 24-48V varieties and the higher you go, the more wattage the amp is capable of putting out.With this Fosi TB10D, I was stunned at how small it is. It is roughly 3/4 to 2/3 the size of the smallish Aiyima A07 (both can use 48V power supplies if needed). The Fosi is very well constructed and has a very solid feel, along with the knobs (not plasticky) - giving it a quality level feel that belies it's inexpensive price. The on/off switch in the front is very solid and convenient, to be sure. Now keep in mind that the TB10D does not have BT capabilities - it’s just a basic amp.As an aside, rather than use the supplied external power brick (32V), I had several high-quality linear power supplies on hand, which I could set to whatever voltage I wanted, up to 40V max. I set one of them to 40V and attached the Fosi TB10D. I then turned on the Fosi and let it warm up for 8 hours before I began listening. Having been an audiophile for well over 55 years now, I'm a firm believer in giving various audio components an initial time period to warm-up/break-in before doing any listening, because for most, sound qualities improve with a good warm-up/break-in period. As an aside, regardless of how long you have the TB10D powered on (I keep my gear on all the time), its case stays cool to the touch.I then connected the TB10D using 10 gauge professional cable (Blue Jeans Cables) terminated on the ends with banana connectors, to the KEF Q150 and Q350 speakers (alternating between the two). The TB10D was fed by a variety of DAC units using a custom-made 8-way in (1 out) RCA switcher custom-built by Maple Tree Audio Design from Canada. This enabled me to use a variety of attached DAC/Head-amp units to determine sound variations with the amp.OK - so let's discuss the audio reproduction characteristics of the TB10D:1. Overall sound signature: Initially - like most other inexpensive class D amps - the sound is a bit thinner, slightly warm, but lacking in feel for that "you are there," immersive experience. As time went on, the overall sound signature warmed up a bit more, became fuller, and had a nice, overall feel to the music. In other words, it is a very "nice" sounding amp to be sure - especially for its ridiculously low price. However, does the term "nice sounding" imply that it is a highly immersive, musical, and accurate sounding amp? Well, no...please read on.2. Sound-staging is wider than some amplifiers, but not in the best category. But given its price-point the sound-staging does not disappoint, considering it's low price.3. Bass capabilities: Very dynamic and fully present (when it's in the recording). In fact, on some recordings, I had to back off on my power subwoofer to balance things out. So for bass heads - once the amp is warmed up - you won't be lacking in the bass department. Does the bass have air and separation like better class AB amps - well, no it doesn't. But there is plenty of bass to go around.4. Midrange and Treble capabilities: Very nice and smooth, however, like all class D amps have a tendency to do at times (but becoming rarer with each new release), some instruments may still come through with a slight "steely" quality to them, like stringed instruments in a large symphony orchestra. However, the TB10D does a much better job than most in this department.5. Depth and air around the instruments: The TB10D does an average job here - nothing exceptional, yet good enough. However, for class D amps in general, this particular intangible quality is often elusive.Audiophile Qualities: For informational purposes, there are some intangible characteristics of "better" amps (i.e. class AB and class A versions) that can best be described as having qualities which cannot be measured in the traditional sense, yet can be experinced when they are present. These intangible qualities include variables such as:a. Being able to accurately convey the ambience of the performing venue.b. Being able to showcase the depth and air around various instruments.c. Being highly immersive - that is, the last veils (regardless of how slight they may be) have been removed between the listener and the music.d. Having correct instrumental timbre - that is, each instrument's tonal qualities are accurately showcased, often-times also referred to as “being musical.”Now, remember - I said that the TB10D is a very good-sounding amp (like many other contemporary models on the market today). However, "Good" does not necessarily translate into being immersive or highly accurate. I say this because overall - again, like many other class D amps - there is a slight (warmish) veil/tonality (in particular with the myriad of instruments in a symphony orchestra) that detracts from the feeling of "being there." This is to be expected really, because after all, this TB10D only costs around $60 to $79 (depending on where you purchase it from). Now if they gave this amp the capabilities like some other Asian made class D amps have - that is, being able to remove and change out the Op-Amps, then that could change the game significantly. But it is not to be - everything is permanently attached inside the Fosi TB10D. The only thing you can upgrade with this TB10D are the power supplies (and the types used).Now here's an important aside - Fosi Audio recently released their much anticipated upgraded BT20A Pro, which is only a few dollars more, and just a few short months later, the highly reviewed and highly regarded FOSI Audio V3 (and by many audiophiles, no less).The difference here also (and it's major) is that there are now 2 dual channel Op-Amps inside both the BT20A and V3 that you can remove and upgrade! This will improve the sound substantially and bring it more in line with what you would hear with class AB amps.Getting back to the TB10D, based on its low price and what you get, I am giving this Fosi TB10D class D amplifiers a 4-star rating - had it the ability to change Op-Amps (thus improving the sound for the most part), I would have given it 5 stars. However, for its very low price, the TB10D punches far above its weight. It is a pleasant amp to listen to and its small size belies the power you get, and it can drive many a speaker - large or small. As I alluded to above, I do strongly suggest that folks invest in "linear" power supplies that make a huge difference with all of your audio components (those components with external power supply bricks). With a linear power supply, there are no hums or other noises. All you get is pure, quiet power that contributes significantly to your audio output. I have several of these with different voltages (link below) that I use, and I also have one that was custom-made to allow up to 40 volts. With this version you can power two devices on the back (not just one), so if you have two devices using the same power, this one linear power supply can power both of them, and it shows you the voltage on the front LCD screen.https://www.amazon.com/gp/product/B09SVK9CQF/ref=ox_sc_saved_title_4?smid=A39KK3JMT5S2I5&psc=1So folks, if you are on a very, very limited budget, you can't go wrong with this Fosi TB10D class D amp. It's price, build-quality and musical pluses - all combine to make it a pleasant experience. However, now that the FOSI Audio BT20 Pro and V3 were released - all with improved internal components and interchangeable Op-Amps, I'd have to give them a much higher recommendation over the TB10D - just sayin.'Now, I realize that all reviews are subjective, and that no two people may agree. Your mileage may vary.