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Fosi Audio BT20A Pro Amplifier Review

Rate this stereo amplifier

  • 1. Poor (headless panther)

    Votes: 3 1.0%
  • 2. Not terrible (postman panther)

    Votes: 33 10.8%
  • 3. Fine (happy panther)

    Votes: 180 59.0%
  • 4. Great (golfing panther)

    Votes: 89 29.2%

  • Total voters
    305

MrOtto

Senior Member
Joined
Nov 4, 2020
Messages
456
Likes
357
Cant remember my had seals. No remains of seals on my package now.

Anyone tried to swap OP-amps for OPA2134 or LM4562NA?
 

Palladium

Addicted to Fun and Learning
Joined
Aug 4, 2017
Messages
657
Likes
804
Cant remember my had seals. No remains of seals on my package now.

Anyone tried to swap OP-amps for OPA2134 or LM4562NA?

Tried both. No SQ difference except more idle tweeter hiss, especially bad on the LM.
 

vazakh

Member
Joined
Sep 5, 2022
Messages
19
Likes
6
Good afternoon!
When the Fosi Audio BT20A Pro is on, clicks with a frequency of about 1 hertz are heard from the speakers. What could be the problem?
 
D

Deleted member 48726

Guest
Good afternoon!
When the Fosi Audio BT20A Pro is on, clicks with a frequency of about 1 hertz are heard from the speakers. What could be the problem?
Does it do it also with nothing connected to the inputs?
 

ghajar77

New Member
Joined
Sep 16, 2023
Messages
1
Likes
0
I currently have the bt20a along with the bose 301v and was thinking of buying the bt20a pro.
But one of my friends suggested sony str-dh190 to me.
I can't choose between bt20a pro and sony str-dh 190.
It is currently available at Sony Walmart for $148, which is a $50 difference to the bt20a pro.
But for me, the quality of the output sound is important.
Does Sony give me good sound quality? Or is it better for me to choose bt20a pro?
 

ClassicGuy

Active Member
Joined
Dec 3, 2020
Messages
145
Likes
102
Good afternoon!
When the Fosi Audio BT20A Pro is on, clicks with a frequency of about 1 hertz are heard from the speakers. What could be the problem?

I just had the same problem with my Lepai amp. For me it turns out to be a faulty AUX cable.
 

NoxMorbis

Senior Member
Joined
Mar 21, 2023
Messages
439
Likes
110
I currently have the bt20a along with the bose 301v and was thinking of buying the bt20a pro.
But one of my friends suggested sony str-dh190 to me.
I can't choose between bt20a pro and sony str-dh 190.
It is currently available at Sony Walmart for $148, which is a $50 difference to the bt20a pro.
But for me, the quality of the output sound is important.
Does Sony give me good sound quality? Or is it better for me to choose bt20a pro?
The Fosi is a mini amp, so if you like small, go with the FOSI. That, and you know how the FOSI performs.
 

neRok

Senior Member
Joined
Oct 7, 2022
Messages
304
Likes
175
Location
Australia
Fosi v3 vs bt20a pro vs smsl a100. What is this better, pls recommend for me.
Fosi V3 and BT20A Pro have similar power, but V3 is cleaner (slightly higher quality). BT20A has more features though, so it depends if you want those features. The graphics on Amazon show this;
fosi.jpg
SMSL A100 is worse, but if the price is good, then maybe it will be ok too.
 

Leethompson

Member
Joined
Sep 3, 2023
Messages
6
Likes
1
Fosi V3 and BT20A Pro have similar power, but V3 is cleaner (slightly higher quality). BT20A has more features though, so it depends if you want those features. The graphics on Amazon show this;
View attachment 312834
SMSL A100 is worse, but if the price is good, then maybe it will be ok too.
I just focus on sound quality, and i connect it to bookself speaker. Thank u so much.
 
D

Deleted member 65547

Guest
The TPA3255 datasheet recommends 53.5V power supply for a load of impedance above 6Ω, tomorrow I will do some experiments increasing from the current 48V for all three of my 3255 amplifiers (Fosi BT20A Pro, V3 and Aiyima A07).
I think I'll have to change the electrolytics on the Aiyima.
 
D

Deleted member 65547

Guest
I just focus on sound quality, and i connect it to bookself speaker. Thank u so much.
I have both the V3 and the BT20A Pro, they are basically the same amplifier, but thanks to the presence of the tone control the BT20A Pro can be made to sound better.
The tone controls are very effective and do not introduce any noise.
The Bluetooth is unusable, I keep it without an antenna, closed on a small 50Ω dummy load.
It's an amplifier that I really like.
 
Last edited by a moderator:

Nicksu

New Member
Joined
Oct 9, 2023
Messages
2
Likes
3
Location
Wirral, England
After reading many reviews (this included) I decided on this model. On amazon in the uk you can only buy it with the 32v power supply (and the price changes almost daily!) so I opted to buy from fosi's own outlet as I could spec the 48v supply and be cheaper than amazon, win win!
That turned out to be a big mistake. The unit arrived all set up in minutes and extremely impressed, well tor half an hour :(
As it warmed up a channel dropped out, lots of testing with speakers, cables, input devices etc and I concluded that it was one of the rca in puts, this was confirmed by touching the rca input and the channel coming back to life, remove the slight pressure and it goes again.
Quick email to fosi customer services, unit less than a week old, faulty on arrival, can I have it replaced. Fosi's reply, could I take it apart and tighten up the input, pardon?
I replied back that it couldn't be tightened as its soldered to the board and that it was a dry joint, could I please have it replaced, fosi get back to me, can I re solder the joint?
I'm getting fairly fed up now, I again ask for a replacement. This time they offered just the circuit board and a link on how to take it apart, reluctantly I agree
New board arrives, swap it over and within minutes starts to fail, varying audio levels channels going in and out.
There is nothing I can recommend about fosi's customer service, if I had bought from amazon I could have just sent it back
Live and learn
 

NoMoFoNo

Active Member
Joined
Mar 1, 2020
Messages
262
Likes
337
Sorry to hear about that @Nicksu. Bummer. I bought directly from Fosi and mine has worked perfectly. It's truly a nice-sounding piece of gear. However, good to know if Fosi customer service is bad. I would think best bets to buy would be from their ebay store with PayPal (for the protection) or from a retailer like amazon.

Are you going to try them again for another new board?
 

Nicksu

New Member
Joined
Oct 9, 2023
Messages
2
Likes
3
Location
Wirral, England
Sorry to hear about that @Nicksu. Bummer. I bought directly from Fosi and mine has worked perfectly. It's truly a nice-sounding piece of gear. However, good to know if Fosi customer service is bad. I would think best bets to buy would be from their ebay store with PayPal (for the protection) or from a retailer like amazon.

Are you going to try them again for another new board?
To be honest, no
I'll try my hand at sorting out the dry joint on the first board, whilst I appreciate I could use the Bluetooth connection, I was using that for a turntable and the rca inputs for a sonos connect
It's a bit disappointing. I was keen to buy the v3 for another room, but having to buy it and then buy another powersupply is a bit silly.
I must admit when it works it sounds great through my old b&w 601's
 

louwii

New Member
Joined
Oct 21, 2023
Messages
4
Likes
4
I've received my BT20 Pro today. I can confirm there's no seal or anything on the box. Ordered on Amazon, shipped from China, arrived in 10 days(!). I was not expecting it to provide such volume to my Elac DBR62! The volume knob is barely turned from its lowest position. Which brings me to my next question.

I'm using the BT20 with a Topping E50. My problem is that the BT20 has no remote, so I can't change the volume easily while watching TV. Can I switch my E50 to pre-amp so I can use the volume control on there? Or is it not recommended?
 

Guddu

Addicted to Fun and Learning
Joined
Feb 10, 2020
Messages
818
Likes
680
I've received my BT20 Pro today. I can confirm there's no seal or anything on the box. Ordered on Amazon, shipped from China, arrived in 10 days(!). I was not expecting it to provide such volume to my Elac DBR62! The volume knob is barely turned from its lowest position. Which brings me to my next question.

I'm using the BT20 with a Topping E50. My problem is that the BT20 has no remote, so I can't change the volume easily while watching TV. Can I switch my E50 to pre-amp so I can use the volume control on there? Or is it not recommended?
If you want to control volume on E50 then change it to pre+DAC, it should work well.
 
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