Fosi Audio V3 Mono Amplifier Review

[whit]

For some reason hifi has a history of opinions and puffery. Businesses have exploited the customer’s limited access to or understanding of information to milk the price/ quality relationship.

Some large part of the world economy consists of con operations. Success in business, politics, religion may be as often based in conning people as in providing real value. Seems like about a 50/50 mix, at best. The successful con will often convince the marks that it is the truth-tellers who are engaged in the conning. Related is the crisis in scientific journals of late. It's become obvious even the top peer-reviewed journals in may fields have published a lot of fraud. If the audio business weren't part con, it would be wonderful and rare.

 

[Killingbeans]

For some reason hifi has a history of opinions and puffery.

Like @maty would say: It's all about the EMOTION!

 

[Inertiaman]

Some large part of the world economy consists of con operations. Seems like about a 50/50 mix, at best.

50/50 huh? Worldwide GDP is ~ $100 trillion. Show me 50 trillion of fraud every year.

Related is the crisis in scientific journals of late. It's become obvious even the top peer-reviewed journals in may fields have published a lot of fraud. If the audio business weren't part con, it would be wonderful and rare.

While this is a legitimate issue/problem, to put it in perspective, the # of fraudulent papers is still <0.5%. And in the vast majority of cases, the journals themselves are not committing the fraud. Paper mills submitting bogus papers using author names without that author's involvement/permission are the primary culprit.

I think your fraud-centric worldview is a bit exaggerated.

My apologies for taking things even further off-topic.

 

[Jon L]

No-one can see that unless they join the group. I'm certainly not going to.

I agree.

 

[Down South]

Colour and transparency are two other "technical terms" that I don't ever recall seeing parameters for on capacitor datasheets.

Capacitors are the new cables. No science. No measurements. Just flowery phooey.

Colour and transparency aren't technical terms and you are stating that all capacitors sound the same - I repeat you have a serious hearing problem. Have you ever had a bona fide hearing test?, if not, why not? If you havn't then you simply don't know how good or bad your hearing is - answer the question, otherwise everything you state is simply an opinion, not basec on scientific fact.

 

[antcollinet]

and you are stating that all capacitors sound the same - I repeat you have a serious hearing problem.

Capacitors don't have a sound - they have electrical characteristics. Capacitance, ESR, Operating voltage etc.

Depending on the circuit they are used in - if you change these characteristics, then it may - or may not - alter the operation of the circuit in an audible way. Most likely change - if there is one - will be the frequency response of the circuit.

However, if the circuit already achieves the necessary parameters for the device to have excellent sound - eg flat frequency response - then putting in "better" or "audiophile" or "expensive" parts, in place of the stock parts isn't going to make things any better.

Bear in mind electronic devices are designed by highly trained engineers, using sound design techniques and calculations, and doing lots of measurements to confirm the design operates correctly with the chosen components. Swapping out those components at random without detailed knowledge of the overall design, and without repeating those detailed design calculations - at best, won't make things worse: Most likely - if you match the capacitance value of the part you are replacing - it will make no difference. If it does make a difference at all, it will most likely make things worse. For example, altering the frequency response away from flat, destabilising amplifier stages, or (in the case of increased bulk smoothing capacitors) increase the stress on rectifiers.

If you are hearing sound improvements from these changes, then by far the most likely explanation for this is sighted listening being subject to cognitive biases - in this case - almost certainly - expectation bias. This doesn't mean you have a hearing problem - it just means your auditory system is just the same as all humans.

 

[Killingbeans]

Colour and transparency aren't technical terms and you are stating that all capacitors sound the same - I repeat you have a serious hearing problem.

That's not what's he's saying. He's saying that if (and that's a big if) a capacitor changes a signal to an audible degree, it's predictable by its electrical parameters and its specific implementation, and those can give you a much, much more useful description of the change, while keeping the risk of fooling yourself way, way lower.

Have you ever had a bona fide hearing test?, if not, why not? If you havn't then you simply don't know how good or bad your hearing is - answer the question, otherwise everything you state is simply an opinion, not basec on scientific fact.

If we got a penny for every time someone tried to use the old you're-deaf "argument" to force acceptance of a wild claim here on ASR, we'd all be billionaires

Have you ever designed electronics on a level where you were tasked with choosing capacitors based on the electrical parameters found in their data sheets, and subsequently verifying the impact of your choice through measurements? -answer the question, otherwise everything you state about the behavior of capacitors is simply an opinion, and wildly at risk of being skewed by cognitive bias.

 

[DavidMcRoy]

Colour and transparency aren't technical terms and you are stating that all capacitors sound the same - I repeat you have a serious hearing problem. Have you ever had a bona fide hearing test?, if not, why not? If you havn't then you simply don't know how good or bad your hearing is - answer the question, otherwise everything you state is simply an opinion, not basec on scientific fact.

Have you ever participated in a double-blind test to support your claims? If not, why not?

 

[dako]

Coupling caps - changing them can make a big difference. I've only once bought into the expensive audiophile thing and regretted it almost immediately - silver foil caps. They were good but the next week bought some cheap as chips Russian K73-16 PEPT ones, slagged off by some old American 'gurus'.

There's a big thread from some years ago on diyaudio 'pept capacitors-One Of The Best.

In a word 'transparent', Like a lot of others on that thread, didn't want to accept what the OP wrote but he was right. He had spent a lot of money on audiophile/fool caps - well worth reading what he wrote.

Of course the real 'true believers' came steaming in with insults as they always do - had never used them, didn't need to - they were right and everyone else was wrong/deluded/stupid. The audiofools believe that to be good caps must be big -the K73-16 aren't. There other PEPT caps that are said to be as good. I've used 10 and 22uF caps in speaker x/overs. One American speaker maker daren't tell his American clients he uses them, they would go crazy - everything COMMIE is bad LOL.

I don't know if I have values that would work in this amp or if it would benefit.

The word transparent is maybe insufficient to describe these caps, it's that other caps colour the sound, these don't. I can only think of one other component that has the same effect - Z foil resistors.

O/A if you can't hear a difference in sound from different caps I think you have a real hearing problem.

When discussing the impact of capacitors on audio systems, it's essential to consider the science behind electronic components and their influence on sound quality. The argument you've presented can be addressed from a technical perspective that clarifies why different capacitors might seem to have varying effects on sound.

1. Capacitor Functionality in Audio Circuits​

Capacitors in audio circuits primarily function as filters, coupling elements, or part of crossover networks in speakers. Their role is to manage the signal path, preventing DC from passing through while allowing AC signals (audio signals) to flow. The fundamental purpose is to ensure the signal is as unaltered as possible, maintaining fidelity.

2. Material and Construction Impact​

The material and construction of a capacitor (e.g., dielectric type, foil, or film material) can influence its performance characteristics, such as Equivalent Series Resistance (ESR), capacitance stability, and dielectric absorption. However, in many audio applications, particularly in the audible frequency range (20 Hz to 20 kHz), the impact of these factors is often negligible if the capacitors are within the appropriate specifications.

• ESR and Inductance: While ESR and inductance can affect high-frequency performance, in audio circuits, the impact is minimal unless the components are severely mismatched or defective.
• Dielectric Absorption: Different dielectrics have varying levels of absorption, which can theoretically influence audio quality. However, many of these effects are outside the range of human hearing or are so subtle that they require extremely controlled conditions to be noticeable.

3. Perception vs. Measurement​

Human hearing is highly subjective, and psychological factors like expectation bias can significantly influence perceived audio quality. This is why double-blind tests are essential when evaluating audio components. Scientific studies have repeatedly shown that when listeners are unaware of the component being used, they often cannot reliably distinguish between different capacitors if the technical specifications are equivalent.

• Expectation Bias: If a listener believes that a particular capacitor, especially an expensive or "audiophile" one, will sound better, they are more likely to report an improvement, even if there is no measurable difference in the output signal.
• Placebo Effect: This is well-documented in audio, where belief in the quality of a component can create a perceived improvement in sound.

4. Capacitor "Transparency" and "Coloration"​

The term "transparent" often refers to a component's ability to not alter the sound. Scientifically, if a capacitor is truly transparent, it means it is not adding any coloration or distortion to the signal. In well-designed audio systems, with capacitors that meet the required specifications, there should be minimal to no audible difference between different types of capacitors.

5. Objective Testing​

The most reliable way to determine if a capacitor changes the sound is through objective testing using equipment like Audio Precision analyzers that can measure Total THD and SNR, and other key audio performance metrics. If two capacitors measure identically in these tests, the difference in sound quality is either nonexistent or beyond the threshold of human hearing. There is no magic going on here.

Conclusion:
While different capacitors may have variations in their construction and materials, their impact on audio quality in well-designed systems is often minimal when objective criteria are applied. The subjective differences reported by users can frequently be attributed to psychological factors rather than measurable changes in the audio signal.
Regarding your suggestion that those who don't hear a difference in capacitors might have hearing problems, it's important to remember that hearing acuity varies from person to person and diminishes naturally with age. However, claiming that those who don't share your perception are suffering from hearing loss is both scientifically unfounded and overly aggressive. Discussions about audio quality should be grounded in mutual respect and objective analysis rather than dismissing others' experiences or knowledge with such claims.

 

[Idrago]

All this caps and cables talk sheesh. Op amp swaps make the real difference, let's start discussing those ,

I received the two V3M ordered and I replaced an opamp position 2 from the XLR input diagram, the next test is the replacement of the second one position 3. I ask those of you who have tried different opamp combinations in the specific configuration of each to specify the preliminary results, opinions and observations. Thank you.

 

[rvsixer]

I received the two V3M ordered and I replaced an opamp position 2 from the XLR input diagram, the next test is the replacement of the second one position 3. I ask those of you who have tried different opamp combinations in the specific configuration of each to specify the preliminary results, opinions and observations. Thank you.

Sorry, my post was sarcasm . If you are truly serious about op amp rolling, this thread already has you covered with the info you seek.

 

[Lux_ury]

Can't wait when new batch of mono blocks get delivered mines, on a ship or plane!
Hopefully we can have more discussions on the amps?
Side note caps
Only test then unsoildered.
Error of UF is important I had way out parameters.
The larger voltage 80v 100v 400v the larger the unit and cost.
Temp ratings 80c 100c makes the cap last longer, but will cost more if it can handle higher temps.(Power caps for amps not filtered ones)
I use chinese cheap mkp and I have used high costly ones, couldn't tell them apart except for the bank notes, evapourating from my wallet. (Upside down wink emoji)

 

[Killingbeans]

I received the two V3M ordered and I replaced an opamp position 2 from the XLR input diagram, the next test is the replacement of the second one position 3. I ask those of you who have tried different opamp combinations in the specific configuration of each to specify the preliminary results, opinions and observations. Thank you.

Here ya go:

Fosi Audio V3 op-amp rolling, has anyone tried it? Snake oil? Or are there actual differences?

A plastic cup holds water. A glass looks better, has better specs in certain areas... but still it just needs to hold water, which it does fine be it crystal, Ikea glass or plastic. And sometimes the "worse" component, a plastic cup, is just what was specified for the job and lasts longer and...

www.audiosciencereview.com

Note the conclusion: Don’t mess with the original design, and avoid randomly swapping OPamps, it’s useless.

 

[korgua]

Almost certainly because no controlled listening comparisons were used. If you look at the TPA3255 datasheet layout examples you will see:

It's almost certain that Fosi have followed this, or the measured performance would be worse. So there is already 'superfast' capacitance right next to the chip where it is more effective than the mod proposed. The mod probably made no difference, which would have been shown by before and after measurements, or recordings that could have been checked for changes.

Don't know where these are, but probably no difference - again no before and after measurements to demonstrate it's doing something useful. It's not impossible that there's a difference (IIRC it came up when opamp-rolling on the 3E integrated showed a difference, traced to a missing cap and the difference in PSRR between opamps) but with the PSRR of modern opamps it would be unusual.

Again no before and after. I don't know the cap specs or the operating conditions - see the capacitor distortion thread for pointers on how this can effect performance.

Thank you for this insight, appreciate it

 

[Bleib]

OK, my 2 units have been sent, they should be fixed by now, correct phase

 

[whit]

While this is a legitimate issue/problem, to put it in perspective, the # of fraudulent papers is still <0.5%. And in the vast majority of cases, the journals themselves are not committing the fraud. Paper mills submitting bogus papers using author names without that author's involvement/permission are the primary culprit.

On academic papers, obviously it's not the journals intending it. But the academics caught have included professors with chairs at good research institutions. It's not "paper mills." It's professors who may have some real achievements, who nonetheless cheat to claim more than they've really achieved (several typical examples, and a much longer list). Or look at the passenger aircraft industry, where Boeing has been engaged in years of fraudulent quality control, even though most of its planes still fly okay. Their $5 billion space capsule at least was good for the one-way trip to the space station. Then we can look at American politics, where if either major party is telling the truth, the other one is deeply committed to fraud. So that's half the world's major commercial aircraft industry, and half of America's political industry, pretty deep into fraud.

To bring this back to topic: The question is to what degree the consumer audio industry is engaged in conning customers. Those making false claims about their stuff still sell items that largely work, in basic terms; you can play music through them. It's not 100% fraud. Is it unreasonable to suspect many are making bogus claims to overvalue their products? Someone selling you speaker wires for hundreds of dollars is really providing something that'll sound different than the same gauge of wire from the hardware store?

 

[Idrago]

Sorry, my post was sarcasm . If you are truly serious about op amp rolling, this thread already has you covered with the info you seek.

Sorry for bothering you for nothing, I asked exclusively for V3M.

 

[Down South]

In all my 40 years of electronics design I’ve never once read a data sheet for a capacitor that had a parameter for “speed.”

I’ll say it again, capacitors have become the new cables. People are convincing themselves, through no science or measurements at all, that “cap rolling” makes a difference.

So you worked in 'electronics design' - what you don't say is - was that work in the audio electronics industry, If so what companies did you work for?

 

[Down South]

It’s fascinating to me that the world of hifi has so much phooey in it. If it was engine design there would be no hesitation in measuring results. Even if it was wine making then blind testing would be commonplace.

For some reason hifi has a history of opinions and puffery. Businesses have exploited the customer’s limited access to or understanding of information to milk the price/ quality relationship. The result is cables and other accessories that cost nothing to make and sell for thousands.

What’s weird is that even without products to buy hifi enthusiasts find ways to create the same illusions for themselves. We see otherwise sensible people placing weights on amps and DACs, lifting cables off the floor, swapping out insignificant parts in new gear, filling speaker stands with sand etc etc without the slightest inclination to objectively measure or test the results.

Fascinating.

Back in 2000 I bought speakers for my wife - Mission 73. The manufacturer specifically stated that adding (dry) sand to the base would aid performance. This was tested by a prominent hi-fi mag in the UK and found to be correct.

For sure there is lots of b/s from manufacturers, so called gurus and eye wateringly priced cables that the makers cannot state the materials/design because they would be copied. Of course this 'argument' is blown away simply all one has to do is purchase said cables, open them up and all would be revealed.

What is also evident that a lot of commercial companies design/build equipment/cables to minimize time and cost completely disregarding basic scientific facts to maximize profit.

If air is the best dielectric why is this method not adopted in construction of audio equipment - because it would mean changing the way that equipment is constructed and of course increase production costs. It's easy to measure energy/signal/input into a cable and at the exit point. Most cables are made using cheap dielectric (which absorbs signal/energy) and tightly wrapped around the conductor/s - air is the best dielectric.

The same b/s argument is trotted out ad nauseum that such cables are expensive, they do not have to be which is conveniently ignored by the scientific - true believers. Nearly all connectors are made from designs dated from the 1940s +, again made from materials that are counter productive to signal flow. The best connectors are no connectors.

The most productive testing should be done on signal flow to avoid signal degradation and loss.

 

[Down South]

Capacitors don't have a sound - they have electrical characteristics. Capacitance, ESR, Operating voltage etc.

Depending on the circuit they are used in - if you change these characteristics, then it may - or may not - alter the operation of the circuit in an audible way. Most likely change - if there is one - will be the frequency response of the circuit.

However, if the circuit already achieves the necessary parameters for the device to have excellent sound - eg flat frequency response - then putting in "better" or "audiophile" or "expensive" parts, in place of the stock parts isn't going to make things any better.

Bear in mind electronic devices are designed by highly trained engineers, using sound design techniques and calculations, and doing lots of measurements to confirm the design operates correctly with the chosen components. Swapping out those components at random without detailed knowledge of the overall design, and without repeating those detailed design calculations - at best, won't make things worse: Most likely - if you match the capacitance value of the part you are replacing - it will make no difference. If it does make a difference at all, it will most likely make things worse. For example, altering the frequency response away from flat, destabilising amplifier stages, or (in the case of increased bulk smoothing capacitors) increase the stress on rectifiers.

If you are hearing sound improvements from these changes, then by far the most likely explanation for this is sighted listening being subject to cognitive biases - in this case - almost certainly - expectation bias. This doesn't mean you have a hearing problem - it just means your auditory system is just the same as all humans.

Quote - This doesn't mean you have a hearing problem - it just means that your auditory system is just the same as all humans - I've read some bllocks in my time but you get a gold medal for that. Hilarious - all humans hear the same - now go and say that face-to-face with a trained and experienced audiologist and see their reaction