Fosi Audio V3 Amplifier Review

[asimze]

• its 8R frequency response curve is far from the curve of a proper TI PFFB implementation, and looks more like the so-called "differentiating postfilter" - which is just a cheap single 50~100pF capacitor connecting speaker out to audio in;

"audio in" , RCA input?
You don't understand the game! In management school, they call it "how to extend the life of a product". For example, don't build 5 features into the product or do it by design. Then V3.1 adds one of the features from the previous list. V3.2 adds the following feature.
So we will have V3, then V3/24, V3/25 will be V3-pro!!! When will they add GND?!
Look at the price of OPA on their website: Sparkos is outrageously expensive and MUSES 02 is twice as cheap. I ask them if they sell the original MUSES 02, no answer?!
Try contacting Sparkos! Andrej will answer all your questions, even when they are stupid. But Sparkos is a TECHNOLOGY company, not a management company.
I bought a V3 too. I'm playing with OPA a bit. OPA 1656 is great! MUSES 8820 has not been developed yet, so I will not comment on it. I'm sorry that I don't have money to buy another SS3602, I have one piece from the previous DAC. That would be quite the party!

 

[PlasticDoc]

"audio in" , RCA input?

Yes, RCA input, thank you.

You don't understand the game! In management school, they call it "how to extend the life of a product".

Well... strange as it may seem, I used to teach... innovation and quality improvement (albeit applied to healthcare)... in a business school.
Audio/Hi-Fi is just a long time hobby.

 

[daniboun]

That is not a question of having a pro edition. You may be missing the opportunity for disruptive innovation with the current V3 development.

Remember that mobile phones, personal computers and photocopiers all started as disruptive innovations. They were not "more of the same" products to serve existing customers, but new products to serve new non-consumers.

In the case of the V3, the aim might be to have the simplest amplifier possible (i.e. RCA input, speaker out, separate on/off switch, volume control, good heat dissipation, no aux outputs, no other gadgets) with flat frequency response and a SINAD of 95dB or better. Keep the good components (coils, capacitors, resistors, heat sink, potentiometer), add a decent PFFB and drop everything else. You will have a winner.

Don't cut corners, as the Ayima A70 seems to have done:

• its 8R frequency response curve is far from the curve of a proper TI PFFB implementation, and looks more like the so-called "differentiating postfilter" - which is just a cheap single 50~100pF capacitor connecting speaker out to audio in;
• its enclosure is clearly not about good heat dissipation;
• its multiple switches, variable frequencies and multiple gain choices, do not even pretend to be a Hi-Fi product; it seems to be (yet another) chi-fi thing for the Chinese domestic market..

I agree : Aiyima clearly oriented the implementation of the PFFB to the sacrifice of design while also neglecting the importance of heat dissipation
But even with a well implemented PFFB you will have a slight load dependency > 30KHZ @8R

Left > 3E Audio 260-2-29A / Right >Aiyima A70

 

[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 (2024 and Beyond)

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 (2024 and Beyond)

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.