Fosi Audio V3 Mono Amplifier Review

[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

 

[Killingbeans]

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?

Doesn't matter. Analogue signal processing is analogue signal processing.

Audio signals do not break the laws of physics, and they do not behave in any magical way.

On the contrary. Most disciplines of electronics consider the audio range to be "practically DC".

You really don't need to work with audio signals specifically in order to know what it takes to filter them effectively.

 

[Killingbeans]

air is the best dielectric.

It is. That's why it's used as the dielectric in high power RF applications, where the loss is critical. Audio electronics is not one of them.

The best connectors are no connectors.

Get yourself some active speakers with WiFi connectivity. Audio nirvana!

 

[antcollinet]

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

Way to misunderstand what was said - you desperately need to do some work on filling in that chip in your shoulder.

First allow me to fill in the full quote to include the context you left out:

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.

Then allow me to clarify:

Your hearing is just the same as all humans IN THAT - just like everyone else - it is subject to cognitive/perceptive biases that can subconsciously alter your perception of the sound in between your ears, and your conscious brain. That actually makes your hearing unique to you - because how that bias works will be dependent on everything you have learned and experienced since the day you were born. You will literally hear different stuff than others which has NOTHING to do with the sound waves reaching your ears, and hence nothing to do with the capacitors you have just changed except in how that alters what you believe about the kit. And is not even consistent since it will change based on your mood/comfort/feelings/sobriety (etc) day to day or even hour to hour.

 

[Down South]

Doesn't matter. Analogue signal processing is analogue signal processing.

Audio signals do not break the laws of physics, and they do not behave in any magical way.

On the contrary. Most disciplines of electronics consider the audio range to be "practically DC".

You really don't need to work with audio signals specifically in order to know what it takes to filter them effectively.

So no actual experience in the audio field - exactly what I thought.

 

[antcollinet]

So no actual experience in the audio field - exactly what I thought.

But actual experience of electronic design - including understanding how and why capacitors influence the behaviour of analogue electronics.

Unlike someone who thinks swapping stuff at random without detailed consideration of the overall design is a valid way to make improvements.

Or are you able to provide the design calculations to explain how your mods interact with the overall amp design to cause the audible changes you claim they do?

 

[Down South]

Way to misunderstand what was said - you desperately need to do some work on filling in that chip in your shoulder.

First allow me to fill in the full quote to include the context you left out:


Then allow me to clarify:

Your hearing is just the same as all humans IN THAT - just like everyone else - it is subject to cognitive/perceptive biases that can subconsciously alter your perception of the sound in between your ears, and your conscious brain. That actually makes your hearing unique to you - because how that bias works will be dependent on everything you have learned and experienced since the day you were born. You will literally hear different stuff than others which has NOTHING to do with the sound waves reaching your ears, and hence nothing to do with the capacitors you have just changed except in how that alters what you believe about the kit. And is not even consistent since it will change based on your mood/comfort/feelings/sobriety (etc) day to day or even hour to hour.

Incredible, barring one word this is a very rational post. But then you drop in the magic word 'believe' You are the 'true believer' and the one with a chip on his shoulder projecting your belief syndrome on to others. You cannot possibly know how others 'hear' music, that is very arrogant but typical of the 'true believer'. I don't 'believe' music I like most other people listen to music. Indoctrination is a terrible affliction. Thought is not reality, only reality is real.

You stay with your indoctrination and I like most will continue to listen to music in the moment because that is where music exists.

 

[rvsixer]

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

Judging by your response, it appears you may have missed (or not bothered looking at) the V3M specific info source I referenced to help you with your question. Good luck.

 

[rwnano]

I have a pair of Irving M Bud Fried SIgnature A 6 transmission line speakers, 2 way, 89 dB sensitivity. I like their sound with my Harman Kardon AVR 3550 - 28 Amperes high current capacity. 65 Watts RMS in 8 Ohms, which is likely 100 Watts out the door.

I'm getting a class AB dual monoblock - 195 Watts * 8 Ohms Stereo amplifier.

How will it compare in sound to Fosi v3 twin monoblocks?
Should I go in for it? will it sound much better? Thank you for your opinions!

 

[avdoc]

I have a pair of Irving M Bud Fried SIgnature A 6 transmission line speakers, 2 way, 89 dB sensitivity. I like their sound with my Harman Kardon AVR 3550 - 28 Amperes high current capacity. 65 Watts RMS in 8 Ohms, which is likely 100 Watts out the door.

I'm getting a class AB dual monoblock - 195 Watts * 8 Ohms Stereo amplifier.

How will it compare in sound to Fosi v3 twin monoblocks?
Should I go in for it? will it sound much better? Thank you for your opinions!

There's no way to predict how it will sound. I purchased the V3M because I wanted a good sounding small amp with an efficient design at low cost. The Fosi has exceeded my expectations. While they're not perfect (I randomly get turn-on thump through my speakers, the amps run hot, and the power blocks were challenging to hide), the size/price/performance ratio are tough to beat.