Fosi Audio V3 Amplifier Review

[PlasticDoc]

But even with a well implemented PFFB you will have a slight load dependency > 30KHZ @8R

Yes, you are right, this is a flaw of the TPA3255 platform that TI has never fixed, hence the need for proper PFFB.

3E Audio has come up with simple and elegant workarounds for both this flaw and the TPA3255 heat dissipation problem.

The TPA32xx chips were designed 10 years ago and the design team has long since left TI. Some of those clever TI Audio people are now at Purifi (which is known for its love of very good feedback-heavy designs).

 

[daniboun]

Yes, you are right, this is a TPA3255 design flaw that TI never fixed (this chip was designed 10 years ago), hence the need for proper PFFB.

3E Audio has just come up with a more elegant workaround for this flaw.

Let s see now how the new Sylph FB100 measures with the advanced PFFB....We will.be fixed soon )

 

[PlasticDoc]

Let s see now how the new Sylph FB100 measures with the advanced PFFB....We will.be fixed soon )

The Sylph FB100 uses the (rather unsuccessful) lower power TPA3251 chip, operating off label at 38V (TI specs this chip as 175W stereo and 36V max),
when it could use the TPA3255 chip, as 3E Audio does, which operates comfortably at 48V (TI specs this chip as 315W stereo and 53.5V max).

I am sure that Sylph Audio has a very good reason for pushing(*) the anemic TPA3251 chip beyond its maximum 36V rating. But this is not reliable and certainly not good engeneering, why not use the TPA3255?

(*) In the past we have seen Aiyima use 50V electrolytic capacitors (instead of the correct 63V) with 48V power supplies. The reason was that these capacitors were special and worked very well... After being caught, they are now using the 63V ones....

 

[daniboun]

The Sylph FB100 uses the (rather unsuccessful) lower power TPA3251 chip, operating off label at 38V (TI specs this chip as 175W stereo and 36V max),
when it could use the TPA3255 chip, as 3E Audio does, which operates comfortably at 48V (TI specs this chip as 315W stereo and 53.5V max).

I am sure that Sylph Audio has a very good reason for pushing(*) the anemic TPA3251 chip beyond its maximum 36V rating. But this is not reliable and certainly not good engeneering, why not use the TPA3255?

(*) In the past we have seen Aiyima use 50V electrolytic capacitors (instead of the correct 63V) with 48V power supplies. The reason was that these capacitors were special and worked very well... After being caught, they are now using the 63V ones....

I disagree... I own both 3E Audio + Sylph FB100 )
Sylph has developed two modules for two different segments : FB100 (TPA3251) + FB360 (TPA3255).
Since when has the TPA3251 been anemic? Read my comparison in the presentation of my projects, (everything is in my signature)
If I were you I would wait for the ASR test of the FB100, which should reach a very good 108db / Sinad ) This is an awesome module, well designed and
it exudes quality !

"ASH-400 Project" Sylph Audio FB-100 Stereo Module with advanced PFFB

Hi amigos, I'm coming back to the forefront with a new project. This time I focused on the Sylph Audio FB100 module, based on a TPA3251 and an advanced implementation of the PFFB. Voltage Gain is factory set @ 14dB (5V/V) on this module. So I intended to couple it to my DAC SMSL D6s which has...

www.audiosciencereview.com

 

[PlasticDoc]

I disagree... I own both 3E Audio + Sylph FB100 )

I have been following your posts for some time and generally agree with and appreciate your comments: "À tout seigneur tout honneur".

However, it is worth noting that the name of the forum is "Audio Science Review"', not "Audio Faith Review".

So let's look at the science, i.e. the published and verifiable specifications provided by TI.

Since when has the TPA3251 been anemic?

From TI spec. sheets:
TPA3251 = 175W , PSU 36V max.,
TPA3255 = 315W , PSU 53.5V max

but, upon closer inspection of the specification sheets, we can see the more realistic values:
TPA3251 = 50W under a 8R load
TPA3255 = 100W under a 8R load

Facts:
- There is a 3dB (i.e., double the power) difference between TPA3251 and TPA3255 chips.
- Sylph uses the chip at 38V, which is above the maximum voltage recommended by the chip manufacturer.
- Reliability suffers and bad things happen when electronic components are persistently used above the manufacturer's maximum recommended voltage.

This is an awesome module, well designed and it exudes quality !

Well, ok, This is starting to resemble the "much better" unit of measure that has been discussed on this forum before.

However, if this were an "Audio Faith Review" forum, faith rather than science would be the appropriate basis for discussion.
In that case, it would be best to defer to an expert: "For those who have faith, no explanation is necessary. For those who don't, no explanation is possible" --St Thomas Aquinas.

If this were an "Audio Faith Review" forum, I would even go so far as to say that the Fosi V3 PFFB Stereo will, in due course, be a better value proposition than the Sylph FB100 or the 3E Audio. --Subjectivism dixit

Warmest regards.

 

[daniboun]

I have been following your posts for some time and generally agree with and appreciate your comments: "À tout seigneur tout honneur".

However, it is worth noting that the name of the forum is "Audio Science Review"', not "Audio Faith Review".

So let's look at the science, i.e. the published and verifiable specifications provided by TI.


From TI spec. sheets:
TPA3251 = 175W , PSU 36V max.,
TPA3255 = 315W , PSU 53.5V max

but, upon closer inspection of the specification sheets, we can see the more realistic values:
TPA3251 = 50W under a 8R load
TPA3255 = 100W under a 8R load

Facts:
- There is a 3dB (i.e., double the power) difference between TPA3251 and TPA3255 chips.
- Sylph uses the chip at 38V, which is above the maximum voltage recommended by the chip manufacturer.
- Reliability suffers and bad things happen when electronic components are persistently used above the manufacturer's maximum recommended voltage.


Well, ok, This is starting to resemble the "much better" unit of measure that has been discussed on this forum before.

However, if this were an "Audio Faith Review" forum, faith rather than science would be the appropriate basis for discussion.
In that case, it would be best to defer to an expert: "For those who have faith, no explanation is necessary. For those who don't, no explanation is possible" -St Thomas Aquinas.

If this were an "Audio Faith Review" forum, I would even go so far as to say that the Fosi V3 PFFB Stereo will, in due course, be a better value proposition than the Sylph FB100 or the 3E Audio. --Subjectivism dixit

Warmest regards.

We will talk after Amir s review )) Science will speak for us amigo --)

Read this in the meanwhile

SylphAudio's High-Performance Amplifier Modules

Would you be interested in making products for car audio using these boards as a base for 4 - 6 channel, 12 V amplifiers? No time yet for other projects, after the 2024 roadmap products, I will proceed on preamp and active crossover. -Lester

audiosciencereview.com

 

[PlasticDoc]

Read this in the meanwhile

SylphAudio's High-Performance Amplifier Modules

Would you be interested in making products for car audio using these boards as a base for 4 - 6 channel, 12 V amplifiers? No time yet for other projects, after the 2024 roadmap products, I will proceed on preamp and active crossover. -Lester

audiosciencereview.com

From that link: Sylph Audio => "Not promoting the TPA3251, but it has a slightly clearer midrange, and finer highs. What's good about TPA3255 though is that it has a fatter midrange sound, making it suitable as a bass/mid amp for a bi-amp system."

It sounds very much like subjectivist marketing from the "Audio Faith Review" forum. Also very informative is Sylph answer, using a pot pouri of wattage, supply voltage and clipping point, to a very good and simple question: "What would be the major benefit of moving from a TPA3255 module to a much less powerful TPA3251 module?".

If this were an "Audio Faith Review" forum, he would risk someone asking "why doesn't he admit that they have a bunch of TPA3251 chips that they now have to sell before they can resume production of the TPA3255 amp?"
But of course we are not in such a forum and we know that all we have to do is wait... for SylphAudio to resume production of TPA3255 based amplifiers. We will see.

 

[daniboun]

From that link: Sylph Audio => "Not promoting the TPA3251, but it has a slightly clearer midrange, and finer highs. What's good about TPA3255 though is that it has a fatter midrange sound, making it suitable as a bass/mid amp for a bi-amp system."

It sounds very much like subjectivist marketing from the "Audio Faith Review" forum.

Also very informative is his explanation using a pot pouri of wattage, supply voltage and clipping point.

If this were an "Audio Faith Review" forum, he would risk someone asking "why doesn't he admit that they have a bunch of TPA3251 chips that they now have to sell before they can resume production of the TPA3255 amp?"
But of course we are not in such a forum and we know that all we have to do is wait... for SylphAudio to resume production of TPA3255 based amplifiers. We will see.

Don't be offended for so little) I don't have any stock shares with them lol
Let s wait for the ASR review.

 

[SMen]

From that link: Sylph Audio => "Not promoting the TPA3251, but it has a slightly clearer midrange, and finer highs. What's good about TPA3255 though is that it has a fatter midrange sound, making it suitable as a bass/mid amp for a bi-amp system."

It sounds very much like subjectivist marketing from the "Audio Faith Review" forum. Also very informative is Sylph answer, using a pot pouri of wattage, supply voltage and clipping point, to a very good and simple question: "What would be the major benefit of moving from a TPA3255 module to a much less powerful TPA3251 module?".

If this were an "Audio Faith Review" forum, he would risk someone asking "why doesn't he admit that they have a bunch of TPA3251 chips that they now have to sell before they can resume production of the TPA3255 amp?"
But of course we are not in such a forum and we know that all we have to do is wait... for SylphAudio to resume production of TPA3255 based amplifiers. We will see.

There is 'objectivism', and there is 'subjectivism', and there is 'cynicism' ... 'Sylph Audio' is an enthusiast, from what I have been able to interpret researching the product! I have no affiliation!

Let's have some faith maybe? And some 'enthusiasm' even?

Personally I like the combination of measurement and listening. Gives me some faith in the product, and the forum, when both are applied.

The Sylph answer was interesting. I am using a 3255 chip implementation with a 36v 11A power supply. This is common.

It seems perhaps the 3255 offers no additional sound / power benefit with this level of power supply (36v). It only offers benefit with a higher voltage (48v to 51v or so) power supply, with the necessary heat management making sure the power supply actually delivers.

 

[DC4582]

I appreciate that this is audio *science* review, but if anyone ends up here just looking to buy something decent at a reasonable price without debating specific transistors or whatever - i did buy the 2024 version Fosi v3 with 48v psu on sale for $88 and I love it. It's paired it with an open box Wiim pro plus direct from linkplay's ebay store ($150) and a pair of emotiva t0 towers I got on clearance ($250). I was just upgrading from some PC speakers so I'm not like an expert, but if that's where you are at then just go for it you will love it, and it's not a huge investment. I used all the money I didn't spend on expensive amps and DACs to buy an RSL 12s speedwoofer.

Also saw some people talking about the v3's volume pot and using upstream volume control - fwiw I have convinced myself that it sounds best with the amp volume at 100% and using the Wiim for volume control with 2vrms output. This is also more convenient since the Wiim has a remote, and you can also set a limiter on the Wiim volume to avoid accidentally blowing your ears off.

 

[SMen]

I appreciate that this is audio *science* review, but if anyone ends up here just looking to buy something decent at a reasonable price without debating specific transistors or whatever - i did buy the 2024 version Fosi v3 with 48v psu on sale for $88 and I love it. It's paired it with an open box Wiim pro plus direct from linkplay's ebay store ($150) and a pair of emotiva t0 towers I got on clearance ($250). I was just upgrading from some PC speakers so I'm not like an expert, but if that's where you are at then just go for it you will love it, and it's not a huge investment. I used all the money I didn't spend on expensive amps and DACs to buy an RSL 12s speedwoofer.

Also saw some people talking about the v3's volume pot and using upstream volume control - fwiw I have convinced myself that it sounds best with the amp volume at 100% and using the Wiim for volume control with 2vrms output. This is also more convenient since the Wiim has a remote, and you can also set a limiter on the Wiim volume to avoid accidentally blowing your ears off.

The quality / value you can achieve right now is just amazing. $88! Gotta keep the right perspective! I spent more than that on the power supply.

 

[Slimer]

I'm thinking about pairing this with Dayton MK402X speakers for use on a computer desk (very near field listening so likely low volume).

Do I need the 48V power supply or will the 32V work fine?

 

[mike70]

I'm thinking about pairing this with Dayton MK402X speakers for use on a computer desk (very near field listening so likely low volume).

Do I need the 48V power supply or will the 32V work fine?

Surely with 5 watts you'll have bleeding ears

 

[Slimer]

Surely with 5 watts you'll have bleeding ears

Sorry if it sounds like a stupid question lol. The reason I ask is I don't quite understand everything about how the power supplies affect the sound. I just want good quality sound without distortion. Will the 32V give me good clear sound as long as I keep it low volume?

 

[Valvetubehead]

Sorry if it sounds like a stupid question lol. The reason I ask is I don't quite understand everything about how the power supplies affect the sound. I just want good quality sound without distortion. Will the 32V give me good clear sound as long as I keep it low volume?

Those bookshelf speakers are pretty low efficiency, I think the 48V would serve you better and leave some headroom.

 

[mike70]

Those bookshelf speakers are pretty low efficiency, I think the 48V would serve you better and leave some headroom.

But the listening position will be at less than 1 meter ... what's the efficiency? 80 dB?
With one watt you have 80dB sound pressure ... and 80dB it isn't "low" ... with 2 watts you have 83dB ... with 4 watts 86dB ...

Consider something more for peaks and the 32 volts power supply is more than enough. I don't think the sound quality will be lower than with 48 volts power supply, at least in that use case.

 

[Brian Hall]

I'm thinking about pairing this with Dayton MK402X speakers for use on a computer desk (very near field listening so likely low volume).

Do I need the 48V power supply or will the 32V work fine?

I went with 48v version. Better to have too much and not need it.

 

[totti1965]

Sorry if it sounds like a stupid question lol. The reason I ask is I don't quite understand everything about how the power supplies affect the sound. I just want good quality sound without distortion. Will the 32V give me good clear sound as long as I keep it low volume?

Hey,
For nearfield stereo you would play very very Loud - even with 1 Watt: Sensitivity is 79.4 dB / Watt an 1 meter. So in stereomode with 2 x 1 Watt you will reach 85.4 dB. This is VERY loud!
With the 34 Watts per channel at 8 Ohm, which the Fosi V3 -32Volt is able to serve, You will get even 15 dB more: each speaker would get 94.4 dB In Stereo a total of 100.4 dB. The Problem is: You will not reach more than 86 clean dB with one of these tiny speakers.
So the 32 V Device is far more than enough!
By the way: The Dayton is fantastic with a little bit of equalizing

Spinorama.org shows us exactly, how to do this (a bit more accurate than the "quick and dirty" Equalizer suggestions of @amirm :
Dayton Audio MK402X
AutomaticEQ (IIR)

Set preamp gain to: -2.9dB.
Type	Freq	Q	Gain
LS	89	1.28	2.93
PK	117	1.75	-1.63
PK	187	1.85	-1.44
PK	391	2.94	2.21
PK	478	1.78	-1.85
PK	714	2.37	1.85
PK	1762	2.3	1.6
PK	6489	1.05	-2.38
PK	12662	0.82	-2.18
Details Download

https://raw.githubusercontent.com/pierreaubert/spinorama/develop/datas/eq/Dayton%20Audio%20MK402X/iir-autoeq.txt

All in all:
Q: At which level of power -roughly speaking- will the Dayton MK402X became ugly?
Answer: It doesn´t love more than 4 Watts.
Q: Is this loud?
A: Yes, Veeeeeeery loud: In stereo more than 100 dB an 1 Meter.
Q: Are there other speakers, which can play louder?
Answer: Most of the other speakers can play even louder!
Q: Is the dayton MK402X a good speaker?
A: With some equalization it is a very very good speaker for the money!
Q: Which app should I use for my windows computer for equalization?
A: Equalizer APO
Q: Which app should I use for my android?
A: Poweramp!
Q: Which app should I use for my apple Computer?
A: Go f...ck yourself!

What Crinacle tells us for IEM is true also for speakers:

look the youtube video from 1:23 min on!

thw

 

[Guddu]

The quality / value you can achieve right now is just amazing. $88! Gotta keep the right perspective! I spent more than that on the power supply.

On a lighter note:
Many times things seem to be good or even better until you put it against another competent product.
And then to avoid arguments and reasoning, we all agree to disagree.
I have a v3 unit that died with issues caused by power on/off deployment within 3 months.

 

[SMen]

On a lighter note:
Many times things seem to be good or even better until you put it against another competent product.
And then to avoid arguments and reasoning, we all agree to disagree.
I have a v3 unit that died with issues caused by power on/off deployment within 3 months.

There goes the value / quality argument (your v3 unit)! . Sorry to hear.

So far, and I do not want to tempt fate, I have been lucky with trying out things like the Aiyima A07 and a balanced BRZHifi 3255. But I am going to try the DIY route with a Sylph or 3e Audio ... and then, I hope 'happily' end my TI3255 / 3251 journey! I've been treating these things as disposable, if only to learn more. Warranties and quality control do matter...