User Review My review of Fosi Audio BT20A Pro 300W x2 class D mini HiFi amplifier

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Hey all
A few of you might have seen my posts about class D amps... So after trying a few class D amps I decided to go for the Fosi Audio BT20A PRO which I bought from Amazon @7999.

It was delivered yesterday and I devoted like 5 hours to test it...
(the demo and testing is still going on and I ll update this review from time to time based on my observations)

Here goes....
Build :
Pretty solid, everything is upto the mark, the aluminium used is of high grade anodised type.
The knobs are sturdy but somehow the one I got has a kinna wobbly volume knob, dunno if it's just me or this is the way it is but all in all the knobs are solid and feel very good especially the copper color of the bigger volume knob gives a great and premium look to this otherwise gray beast (there is a blue color as well but it seems it's not available here in India at this time)
The back connectors and sockets are placed pretty close to each other, with some small maneuvering everything can be pushed, tied and fixed though.

Please mind that it takes I guess smaller pinned banana connectors.. I didn't know and purchased the full sized (longish type, 8 in total) ones which upon connecting would remain nearly 50% outside of the socket, hence had to connect bare wires with speaker out ports.. TBH I found this method of connecting wires kind of easy, no non sense type and they are connected pretty tight with the ports.

Accessories
The bluetooth antenna is no nonsense standard & decent one which you have to screw yourself.
POWER SUPPLY : I was expecting a 48V power supply but seems fosi doesn't ship that anymore, the supplied 32V is sufficient for my needs..
The wire lengths with the power supply adapter are adequate, the block and wires, all look decent and feel study enough . Checked its voltage with multimeter & it does produce what is claimed 32.4V to 32.5V.

Functionality..
Bluetooth connects in a jiffy and the coverage is good.
Kinna tricky sometimes to get the connection changed but by and large it's easy to switch from BT to RCA.
The knobs give good feel while using and operating them... The volume knob can be pushed in & within 5 seconds it erases bluetooth memory so you can pair another source...

There is also a socket of pre out at the back which can be used to supply signals to an active subwoofer which is awesome in my view... But I dont think I ll ever need that as the amp gives enough thump already with my 2.0 passive speakers. This same socket can be used to connect this amplifier as a preamp to another amplifier if you want..

Audio quality
Please note I use my SONY BOOKSHELF SPEAKERS ( I call them bookshelf as they perform really well and partly coz I don't have the machine) with this.. The ones which came with Sony MHC-Az2d music system. (edit attaching pics of them)

Via Bluetooth it sounded pretty decent (please note I use Spotify with highest streaming audio quality on an iPhone)
Via RCA I stream via my Google chromecast audio and the sound is even better.

Over all its pretty loud, the tone knobs do a good job and the best part is there is a neutral point for both bass and Treble exactly in the center so you get a good reference point..

The low freq response is awesome which is genuinely deep, the high freq are pretty good too but may be a bit more wanting like 10% lesser than the bass response... But that's just me... Over all it has played everything nicely that I have thrown at it... Mids are pretty good ( as you have to manage them via your preamp etc, you can further enhance them as well but they are pretty good already )
For info - I tested by turning the EQ in Spotify off and setting the bass and Treble levels on the amp at 0, sound was ordinary but as soon as you gradually crank up both around 3 o clock the bass is sufficient and at around 4 to 5o clock the highs are enough..

Be it the jazz, or Bollywood music, or ghazals by Mehdi Hassan and Live Indian Classical renditions in both vocal ( by Kishori Amonkar, Lakshmi Shankar Abhijeet Pohankar and many many others) and instrumental( sitar, sarod, santoor, tabla, flute etc) it played everything nicely (of course you have to adjust the knobs according to the type of music as well as the source quality)

But one thing is for sure, via Google chromecast audio (which technically means that there is a proper DAC before the RCA input ( as the GCA has a dedicated DAC in it) this thing just sounds so great..

Please note : Type of drivers (speakers) plays another huge role so please use atleast half decent ones with these...
I will hook up another pair and edit my review in a few days and add more details about how it peforms with them...

All in all I am pretty happy, would have loved a fully functional remote and a knob to manage the mids too (I know that's tricky)
Would have loved to have couple of more connectivity options like optical etc but that's just for academic reasons only, BT and RCA for me are more than enough..

All in all pretty good small package
Would recommend it as tpa3255 chip performs extremely well and this little beast is loud really loud but the audio doesn't distort at higher levels ( haven't fully checked tbh)

For a budget freak like me who after a certain age looks at the price first and value later this thing is just so so so good... The other class D amps thatI I used in last few months also performed very very well... (size, budget, firm factor and options, based on them Class D would be extremely popular among music enthusiasts snd audiophiles in future if not already)
This TPA3255 based Fosi bt20a pro amp has a wider stage of sound, audio is fuller, the thump is nice and pleasent ( for me ) audio notes are decently distinct and boy it is loud...
A decent input signal and half decent output drivers will let you distinguish it from your existing system....

Thanks

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Congratulations! Nice, simple and on-point review. Fosi Amps are generally well made and I have also been using a Fosi Audio Amplifier in one of my setups:

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The Fosi Audio Amplifier is a TDA7498E based unit. And as you correctly mentioned in your review, these little buggers pack some serious punch and can get LOUD!

Btw, those Sony speakers definitely remind me of the 90's component music systems which would be there in every household! I still have mine... the CDP unfortunately doesn't work anymore but the Radio Tuner, Tape Deck and Auxiliary still work well. Is your Sony AZ2D still working?
 
Congratulations! Nice, simple and on-point review. Fosi Amps are generally well made and I have also been using a Fosi Audio Amplifier in one of my setups:

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The Fosi Audio Amplifier is a TDA7498E based unit. And as you correctly mentioned in your review, these little buggers pack some serious punch and can get LOUD!

Btw, those Sony speakers definitely remind me of the 90's component music systems which would be there in every household! I still have mine... the CDP unfortunately doesn't work anymore but the Radio Tuner, Tape Deck and Auxiliary still work well. Is your Sony AZ2D still working?
Nice looking setup wow 2 amps and one preamp and another monster below them all... Awesome..
Well the az2d died long back and was given to the kabadi a few years back... But I loved that system for the touch panel and clear audio though it didn't have much low frequency response
... I have another system lying that's RV50 but the tape deck as well as the cd player section isn't working... So it's a dodo as well..
But have four pairs of speakers now one pair from az2d and other from RV50.

I ll be honest they sound superb and I don't think I ll buy any passive pair now.. Unless I want a more powerful pair..
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Right, so I was confused, why I wam not able to stream high resolution audio files properly as they were sounding so muffled as if they are 32kbps quality when infact they were 24bit/96khz..
I have a fast network, google chromecast audio supports 24bit/96khz audio and vlc doesn't mess with audio signals as such if it's being streamed over wifi....

After assuming that all equipments in my chain might be optimally working, I sent an email to fosi and guess what they told me that one can input only audio signals of 24bit/48khz to this amp, via Bluetooth or rca sockets. (RCA????, but they are meant for analogue input right?) . I I doubt if Bluetooth would be any good as it just supports sbc/aac codecs and no support for aptx, aptx ld and LDAC..

Thought of updating you guys.. If at all the staff allows me to edit my original post, I ll add this info at the top.

Thanks
 
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Sorry, not HDR. In Google Home settings for Chromecast Audio, there is a setting to enable Full Dynamic Range. If this is not turned on, do try that and see if it makes any difference
Yep that has been on since the beginning..
The issue is with fosi, it's not able to process anything over 48Khz of sampling frequency...
So from now on all my files will be 24/48 or below atkwat the flac ones
 
Yep that has been on since the beginning..
The issue is with fosi, it's not able to process anything over 48Khz of sampling frequency...
So from now on all my files will be 24/48 or below atkwat the flac ones
How is the Chromecast audio connected to the Fosi amp ?
 
Then the Fosi amp is not seeing the digital signal at all. So any bit-rate or sample-rate related problems could not be due to the Fosi amp
You are right, I didn't pay attention really that 24bit/96KHz are specifications of a digital signal, analogue ones don't have that...
Wondering why the fosi guys said that..

This make me wonder what's the bottle neck then.. Gcca can handle high resolution, that's proven and vlc might not have a role, then I guess it's the hdd or the router to which hdd is connected that's not letting it send the high res signals...

Need to again troubleshoot...
 
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