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Fosi Audio BT20A Pro - Opinions and Comparisons

I would like to ask if I can change opamps, using others , apart from those recommended by the manufacturer, for example muses 01 , muses 8920 etc.
 
Thank you. I was trying to do it on Amazon but now solved. Appreciated.
 
I was going to buy the BT20A Pro, but I really wanted something simpler with no Bluetooth at all. So I ended up backing the new Fosi V3 instead.
 
I replaced a BT20A with the new BT20A PRO for my ceiling speakers. I have an Apple TV connected via bluetooth to watch movies and listen to music. There are so many upgrades including the wattage that's it's hard to tell exactly what accounts for the big jump in sound quality, but I'm very happy I upgraded! It's not a MA352 (I did compare it haha) but for $70 (thanks for the 30% discount Fosi!) I could not be happier. Now let's see how much I can get for the BT20A...
 
I was going to buy the BT20A Pro, but I really wanted something simpler with no Bluetooth at all. So I ended up backing the new Fosi V3 instead.
It will be interesting to see what the V3 measures liked but Fosi have been getting better and better so no doubt its a good Amp, but I do like my BT20A Pro - bluetooth is effectively optional so I don't think affects the sound quality though I run with the RCA inputs from a DAC.
 
I replaced a BT20A with the new BT20A PRO for my ceiling speakers. I have an Apple TV connected via bluetooth to watch movies and listen to music. There are so many upgrades including the wattage that's it's hard to tell exactly what accounts for the big jump in sound quality, but I'm very happy I upgraded! It's not a MA352 (I did compare it haha) but for $70 (thanks for the 30% discount Fosi!) I could not be happier. Now let's see how much I can get for the BT20A...
Are they comparable? Since Fosi BT20A PRO is $70 and mcintosh MA352 is $7000, they're not even the same thing.
 
I replaced a BT20A with the new BT20A PRO for my ceiling speakers. I have an Apple TV connected via bluetooth to watch movies and listen to music. There are so many upgrades including the wattage that's it's hard to tell exactly what accounts for the big jump in sound quality, but I'm very happy I upgraded! It's not a MA352 (I did compare it haha) but for $70 (thanks for the 30% discount Fosi!) I could not be happier. Now let's see how much I can get for the BT20A...
I wish I could get the 30% discount! You went from a TPA3116 chip to TPA3255 chip.
 
Are they comparable? Since Fosi BT20A PRO is $70 and mcintosh MA352 is $7000, they're not even the same thing.
Technically speaking, they were comparable. I compared them myself :) But no, different league, especially with my power hungry B&W 702 Signatures. But, not 100 times better!
 
Technically speaking, they were comparable. I compared them myself :) But no, different league, especially with my power hungry B&W 702 Signatures. But, not 100 times better!


[ B&W's sensitivity was a high 90.2dB(B)/2.83V/m, confirming the specified 90dB. The 702 S2's nominal impedance is specified as 8 ohms, with a minimum value of 3.1 ohms. ]

And about 3.4 Ohms at... 700 Hz!!!!!!!
 

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[ B&W's sensitivity was a high 90.2dB(B)/2.83V/m, confirming the specified 90dB. The 702 S2's nominal impedance is specified as 8 ohms, with a minimum value of 3.1 ohms. ]

And about 3.4 Ohms at... 700 Hz!!!!!!!
Is that good or bad? I'm no audio engineer...

Mine are 702 Signature not S2.

https://www.whathifi.com/reviews/bowers-and-wilkins-702-signature

 
Worst impedance graph (3.1 and 3.3 Ohms) -> they need a good amplifier with amperes to sound good with discrete transistors, without chipamps (either class D or AB, or at least two by channel). Or a powerful tube amp.

And...

It will certainly present a challenging load down at 80Hz, where you can see a 4.7Ω impedance combined with a –68 degree phase angle (the phase angle is shown by the light blue trace).

A cheap class D is not a good idea. Or a modern AV.
NUkj9VjUDizXENBT8UVqPM-1024-80.jpg
 
Worst impedance graph (3.1 and 3.3 Ohms) -> they need a good amplifier with amperes to sound good with discrete transistors, without chipamps (either class D or AB, or at least two by channel). Or a powerful tube amp.

And...



A cheap class D is not a good idea. Or a modern AV.
View attachment 282234
When I first got them (used for $5K) I found them even worse than my 683s. I was driving them with a MA252. I then read they need a LOT of power so I upgraded to a MA352 (sold my year old MA252 for $100 less than I paid for new!
Worst impedance graph (3.1 and 3.3 Ohms) -> they need a good amplifier with amperes to sound good with discrete transistors, without chipamps (either class D or AB, or at least two by channel). Or a powerful tube amp.

And...



A cheap class D is not a good idea. Or a modern AV.
View attachment 282234

I went with the latter. Based on my subjective perceptions only. Then I added a REL S5 SHO. Still very happy 2 years later, although I hope to one day have the opportunity to compare to a pair of well-measuring Genelecs or Neumanns.
 
This bt20a pro with 32V 5A power brick should power 4 micca m-8c ceiling speakers, wired to present a 2x4ohm load, in a smallish room at casual listening volume just fine right?
My wife wants her cheap bt mono speaker upgraded for her yoga practices...
 
I just ordered one with their 48V power supply from AliEx and found a pair of genuine BB OPA2134PA's from Amazon for rolling. Has anyone here done similar upgrades with theirs? I plan on hooking up a pair of JBL Stage A130's and maybe a small sub to round things out.
 
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