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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 58.8%
  • 4. Great (golfing panther)

    Votes: 90 29.4%

  • Total voters
    306

Fosi Audio

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Sure. But it still doesn't change rhe fact that there at all times is standing still air inside. This is inherently bad. Still air doesn't transport much heat. Still air gaps actually insulate. I don't get why there isn't just a handful of drilled holes.
Makes it seem like a work of haste. -Or an oversight.
It's true that some amps are easy to get overheated and shut down shortly. However, we have tested the BT20A Pro strictly and it proved it can work quite stably with the 48V power supply. So basically drilling holes in its case is not very necessary. Anyway, your consideration will be taken into account. We will evaluate adding vents to it.
 
D

Deleted member 48726

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It's true that some amps are easy to get overheated and shut down shortly. However, we have tested the BT20A Pro strictly and it proved it can work quite stably with the 48V power supply. So basically drilling holes in its case is not very necessary. Anyway, your consideration will be taken into account. We will evaluate adding vents to it.
Thank you for your response. I don't doubt you have tested it. -For how long and with what power output?

I know most class D amps integrated into thousands of utilities like soundbars, subwoofers, bluetooth speakers, TV's etc. Here the thought process seems to be something along the lines that the duty cycle of use is low enough so no cooling is necessary.

I think differently of a dedicated amplifier which advertised power output is just high enough that the use case can be to drive decent speakers and thus pulling more power.
 

laudio

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Dec 30, 2019
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Doubt cooling with holes is that necessary (having run a TPA 3255 for years at 48V). The anecdotal evidence isn't there about heat concerns. This is not a Pioneer AVR, the measurements speak for themselves - seems like a good amp. At the price it's buy it try anyway right?
 
D

Deleted member 48726

Guest
Doubt cooling with holes is that necessary (having run a TPA 3255 for years at 48V). The anecdotal evidence isn't there about heat concerns. This is not a Pioneer AVR, the measurements speak for themselves - seems like a good amp. At the price it's buy it try anyway right?
Encapsulating power electronics generally is not a great idea. But at least the magical smoke is sealed in if something goes wrong.. ;)
 

maty

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How it sounds? BT20A Pro with Various Op-Amps Demonstration

FOSI BT20A Pro opamps.png


I wrote:

OP249
2º OPA2604

It is surprising how well the familiar NE5532 stands the test of time.

The worst, RM4559
 
D

Deleted member 48726

Guest
The comparison with the tube amp at the end.... brutal. The class D amp sounded like someone squeezed Nora's throat with both hands and forced her to sing at the gunpoint. Ouch.
Yeah, there sure is a spectacular difference! We don't see the mic and speaker setup though. I much prefer the sound from the tube on that video. Weird they let that difference show from a marketing POV. I know that there is substantial price difference but still.
 

maty

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You people make me LOL: On one hand you insist that measurements and linearity mean EVERYTHING, and here you glow over an obviously COLOURED signal from a tube amp. You can't have both. :D

This amplifier is for listening to current commercial music, badly produced and with little dynamic range. For higher quality recordings it is... a toy, make no mistake.

For the tweeter, another type of amplification (A or AB) is much better, less problematic (except for the much more expensive class D Purifi, Hypex Nilai500DIY).
 

Talisman

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This amplifier is for listening to current commercial music, badly produced and with little dynamic range. For higher quality recordings it is... a toy, make no mistake.
This sentence is nonsense, it's just an unmotivated attack and not justified by measurements. It allows you to manage good dynamics having a low background noise and managing dynamic peaks over 150 watts at 4 ohms.
This is bar talk from those who persist in hating a product category
 

ClassicGuy

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Dec 3, 2020
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Am I getting the sense that some people are making feature requests on a product they will never buy or use? Some statements feel like "I will never drive a bus, but can you please add a fifth wheel to it?"
 

Joe Smith

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This amplifier is for listening to current commercial music, badly produced and with little dynamic range. For higher quality recordings it is... a toy, make no mistake.

For the tweeter, another type of amplification (A or AB) is much better, less problematic (except for the much more expensive class D Purifi, Hypex Nilai500DIY).
Disagree...these small Class D amps work just fine for a wide variety of music and in a wide variety of use cases. I think for someone who wants to play music regularly at 90+ dB, there are perhaps better current choices, either a class AB amp or Hypex/Purifi builds.
 

Joe Smith

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Am I getting the sense that some people are making feature requests on a product they will never buy or use? Some statements feel like "I will never drive a bus, but can you please add a fifth wheel to it?"
No, as to me, I like to see these amps involve, and I currently own SMSL SA-50s (older), a variety of home-built TPA3116 amps, Aiyima A04 and A07, and the SMSL AO-100. I think it's great that Fosi, Aiyima, SMSL and other are really pushing forward with the less expensive Class D range. At the same time, Schiit is putting out some nice lower watt Class AB amps. It's a great time to swim in the audiophile shallow end of the pool, in my opinion. For me personally, my next amp investment may be a Buckeye Hypex, don't really need it for the room sizes I have, but eventually I can probably justify buying one ;)
 

sound67

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Jan 31, 2023
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This amplifier is for listening to current commercial music, badly produced and with little dynamic range. For higher quality recordings it is... a toy, make no mistake.

For the tweeter, another type of amplification (A or AB) is much better, less problematic (except for the much more expensive class D Purifi, Hypex Nilai500DIY).
Sorry, but this is just a GARBAGE argument.

No, I'll take it back.

I'm not sorry.
 
Last edited:

sound67

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I guess you're one of those people who also think that speaker and RCA cables have individual sound profiles. ;)
 
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