Fosi Audio BT20A Pro Amplifier Review

[solderdude]

With 48V input, amp beind used balanced you can get about 34V RMS voltage when the output can swing to the PS rail (switch mode) = 289W in 4 ohm for very, very short impulse in music, type moments.
This is 0.15dB short of 300W.

I am sure continuous it would not be possible unless the 48/5 rating of the PS is continuous and can deliver more for short durations.

 

[TheBatsEar]

I don't know of any Japanese ABs that cost 100 euros, and certainly none under 400 that deliver real 100watts into 8 ohms

Neither do i, but this Fosi doesn't deliver 100W into 8ohms unless you buy the bigger power supply, which costs something as well, say 40€. So you are at 140€, not sure if sales tax is included, but let's assume it is.

This can be bought for 190€, so 50€ more.

I am not familiar with other brands offerings, but i guess if we looked, we would find similar things from Onkyo, Sony and so on, maybe an with even smoother frequency response and more power.

Don't get me wrong, i voted fine for this Fosi one, but it's only a good deal if you ignore the competition.

 

[TheBatsEar]

289W in 4 ohm for very, very short impulse in music, type moments.

Ok, fair enough.

 

[Talisman]

Neither do i, but this Fosi doesn't deliver 100W into 8ohms unless you buy the bigger power supply, which costs something as well, say 40€. So you are at 140€, not sure if sales tax is included, but let's assume it is.

This can be bought for 190€, so 50€ more.

View attachment 281986

I am not familiar with other brands offerings, but i guess if we looked, we would find similar things from Onkyo, Sony and so on, maybe an with even smoother frequency response and more power.

Don't get me wrong, i voted fine for this Fosi one, but it's only a good deal if you ignore the competition.

The as 201 Gives 100+100 into 8 ohms at 10%thd..... we are comparing apples and oranges.

In addition, I paid about 100 euros with a 48V power supply

 

[JktHifi]

The as 201 Gives 100+100 into 8 ohms at 10%thd..... we are comparing apples and oranges.
View attachment 281999
In addition, I paid about 100 euros with a 48V power supply
View attachment 282000

8 ohm 100 watt, maximum 4 ohm 115 watt

 

[Talisman]

8 ohm 100 watt, maximum 4 ohm 115 watt
View attachment 282009

The specifications must be read and understood well.
It's not just Chinese companies that artfully tweak specs to make them look better

 

[GrayA]

I think you want Fosi Audio TB10D, they both TPA3255.

Fosi Audio TB10D Amplifier Review

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. We have the typical compact desktop aluminum case. Controls feel nice for the class. Tone controls are not centered...

www.audiosciencereview.com

That's what I have!

 

[asnow]

I'm about to order this amp but I have a question about the PSU. having read right through this thread is the 48V going to cause heat problems. Seeing as there is no venting on the case top I would anyway drill venting holes. Once I get some definitive answers I will know what PSU to order.

I just received my BT20A Pro with the 48V supply. After playing for 2 hours at full volume on the BT20 at about 83 dBc with B&W 602s, the power supply was at 63 degrees F and the amp case was at 81 degrees F. The room temperature was 61 degrees F (my cellar). Hope this helps.

 

[SWSL]

Wow, HPF, sub-out, Multiple settings for the crossover frequency, got it.

How much power do you want?

How about just adding offering a switchable high pass filter at 80hz ? And please do keep the preamp out for connecting a powered sub or any other amps.

 

[Kimbrough Xu]

How about just adding offering a switchable high pass filter at 80hz ? And please do keep the preamp out for connecting a powered sub or any other amps.

Why not 60Hz?

 

[TheBatsEar]

Why not 60Hz?

Most small speakers don't reach it. Optimal would be a switch to use 80, 100 or 120. Only 80 is a good compromise.

 

[muraha]

I've bot one recently, but I guess I have a problem with pre-out. Has no signal with it.
I think it may be because I connect it via BT right now.
Does pre-out work with BT connection or with RCA only?

 

[yodog]

Many thanks to Amir’s honest review and measurements. Happy Easter to Amir and all ASR fans!

We really appreciate ASR which allows us to listen to and gather users’ feedback on our old models. We absorbed a lot from the voices and develop this BT20A Pro. It’s not a perfect amp but we will keep making effort to improve it.

Here we want to give an exclusive 20%-off discount promo code for the BT20A Pro to all ASR fans. (Valid from today to April 30.)
20APROASR20

Hope you will be interested in this new amp!

Could you pm me a discount code that would work for this? Preferably a code that will work on Amazon as well? ?

 

[Fosi Audio]

I've bot one recently, but I guess I have a problem with pre-out. Has no signal with it.
I think it may be because I connect it via BT right now.
Does pre-out work with BT connection or with RCA only?

It works both with BT and RCA. Did you connect an active subwoofer to the pre-out?

 

[Jacob8275]

How does the soft start thermistor work? Fosi mentioned that the on/off toggle is not just a standby but a complete power off. My actual question is if it would be ok to turn the amplifier on/off via the AC mains (to the power supply brick)? This method was not recommended with the Aiyima A07 as the power surge would be straining the PSU filter caps too much. But this could potentially be solved here. Anybody know?

You can turn off/on the amplifier via the AC mains, but it will give the speakers a POP sound which will be harmful to the speakers, also this is a tedious operation.
If the power switch can't turn off the machine, once the power supply connected, the machine is on and the components inside the machine will start working, the life of the machine will be reduced in the long run. In addition, this design is also unsafe, if people are not present and the machine keeps working, there may be overheating problems that can lead to fire.

The A07 power switch is not actually turn off/on the machine, it is a switch to mute/on the sound.

 

[Lennart]

Bluetooth is always on and has priority over RCA. This was confirmed by Fosi rep.

This is such a dealbreaker for me. I live in a student complex, and it would be just a matter of time before someone would start messing with me.

 

[trivium]

Building a set of hitmakers, they are not sensitive as everyone is aware, though I dont routinely listen to 100DB levels of music at my desk. Would anyone pair this Fosi with the the Hitmakers which as sensitivity of ~80DB. Also it seems the BT20A Pro fairs alot better than the TB10 which is riddled all over amazon, the BT20 Pro is the superior choice? or?

 

[TonyJZX]

i feel like this is what's called "dumb bluetooth'

smart bluetooth is how its implemented on a few of my amps.... crikey i have three amps I can think of that have BT

its a switchable thing done in software... you have to go thru the menu and turn it on AND/OR you can set a 4 digit passcode etc. etc.

BUT that takes software control that you cant expect in a $100 device? this is the thing.. no one can do this at this level and so if its not done well you may as well buy the Aiyima A07 or the upcoming Fosi V3 and let your bt dac do the talking as it were.

 

[Svenimal]

This is such a dealbreaker for me. I live in a student complex, and it would be just a matter of time before someone would start messing with me.

Yeah, it can be pretty annoying indeed that you can't switch off bluetooth. As it is now, anyone within range can connect to the amp without you having any control over it. That is my only negative, for the rest I'm very happy with it and for the money it's a great deal.

 

[trivium]

So wants the difference between the the BT20A Pro and the TB10D, they use the same chips?