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Fosi v3 Mono | TPA3255 PFFB | Balanced | [First Look from Fosi FB]

Negatywny

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daniboun

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i think we know that a normal stereo tpa3255 has something like 70-90w

one might ask how a dual box, dual 48v 5a psu setup you will put up with to achieve maybe 130w in mono? at best? we are not expecting a heap more

and i dont like the idea of such a messy setup

wait for what fosi does in response to the A70

A well done TPA3255 PFFB Mono should give (with a 500W PSU @ 48V)

@the knee :
About 190W @ 4R
About 100W @ 8R

If you want to get an idea, you have to compare chips that are comparable to each other. In this case, this Fosi Mono has two main competitors:

- 3E Audio 480-1-29A Mono TPA3255 / PFFB
- Sylph Audio FB360 mono TPA3255 / PFFB

A well made TPA3255 with a good implementation of PFFB should give about :

-103db Sinad @4R (with 20db gain) or more or less 0.0007% THD+N
In my previous threads, we demonstrated that with a lower gain we improved the value of Sinad
With a 16db gain, you can reach about 105db Sinad @ 4R


@sarieri If you want to compare the RA3 to any good TPA3251 amp, get the PA5 for instance that reaches more than -105db Sinad@4R with 19db gain. (vs 18,6db gain for the RA3). What you also forget to stipulate is that the RA3 is a Rack Mount type amp (19') and therefore it is not specifically intended to be displayed in a living room.
What's more, the RA3 does not even have CE certification and for good reason it is banned from export in several European countries. So of course it's an excellent amp but at the sacrifice of safety standards

If we look at the RA3 closely, we see that they just disarmed the shell of the PSU Brick from the PA5/PA5II to insert it into the case
As for the RA3 TPA351 module, it is roughly that of the PA5II readjusted



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mike70

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there´s a simple shadow ... in the left switch you can see the same effect.
 

MCH

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And if it's not RCA, what could it be? Turbo boost? :D
 

somebodyelse

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Yes, with digital volume you lose 1dB DR everytime you dial down 1dB volume. With analog volume, you lose less than 1dB. That’s why I was talking about RA3’s R2R volume.
Technically correct, but if you can't hear the DAC's noise (which should be true with any decent DAC these days) it makes no practical difference.
 

sarieri

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Technically correct, but if you can't hear the DAC's noise (which should be true with any decent DAC these days) it makes no practical difference.
I agree. I'm just saying it's technically better.
 

daniboun

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Apart from the advantage of infinite channel separation with a mono poweramp ….The mono power amp will have separate power supplies for the two stereo channels - in an ordinary stereo tpa3255 the powersupply at 32V 5A will be shared by two channels, having only 2.5A per channel at full blast, both channels.

So there is a real benefit with mono poweramps in this case because the current capability is in reality doubled.

A Stereo version with a 48V/10A PSU would make everyone agree....
 
OP
Guddu

Guddu

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I'm guessing this will be the standard use case as well... people hooking up monoblock amps to their discman!
You never know how creative someone be for just a nicer looking picture ;)
 

Yorkshire Mouth

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So, just thinking about the price. You need two (unless you're using it as a centre channel), so when we're comparing to other amps:

Topping LA90 $800, 50% = $400
Topping PA7 Plus $549, 50% = $275
Topping PA5 II Plus $290, 50% = $145
Aiyima A70 $220, 50% = $110

That's just so, when the price and reviews are out, we have a level playing field. ;)
 
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gwing

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So, just thinking about the price. You need two (unless you're using it as a centre channel), so when we're comparing to other amps:

Topping LA90 $800, 50% = $400
Topping PA7 Plus $549, 50% = $275
Topping PA5 II Plus $290, 50% = $145

That's just so, when the price and reviews are out, we have a level playing field. ;)
Any reason not to include the Aiyima A70 in that calculation?
 
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