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Fosi Audio V3 Mono Amplifier Review

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 12 1.9%
  • 2. Not terrible (postman panther)

    Votes: 19 3.0%
  • 3. Fine (happy panther)

    Votes: 122 19.5%
  • 4. Great (golfing panther)

    Votes: 472 75.5%

  • Total voters
    625
it's 'physical' and so I don't worry about sudden max volume surging through to my speakers.
Not really any more reliable than any software controlled volume.

The relays are controlled from a microcontroller, and the "state" (volume) has to be remembered when powered off (and not corrupted/lost while powered on). It is no less likely to forget what the volume should be than any other system not consisting of an actual potentiometer.

In an ideal world in this type of system, the volume "value" should be checksummed, and revert to minimum if the checksum doesn't match. I'm not sure if the designers of these types of devices are that careful though.

The best defence from software controlled volume, is to use attenuators on the input to the amp which limit the maximum volume to a safe level for your speakers - even when the volume control is set to max.
 
Unless you need extra features or extra inputs from the Topping, you can eliminate it and just use the Wiim Pro Plus as your preamp, streamer and dac. The Topping won't sound any better than the dac in the Pro Plus.
I think the Wiim Pro Plus is single ended only. So this loses the ability to switch between RCA and Balanced to the Monos from the Marantz (single ended) @CReeDeR mentions. I'm loving the balanced connections through to the V3 Monos because it works in my set up.
 
I think the Wiim Pro Plus is single ended only. So this loses the ability to switch between RCA and Balanced to the Monos from the Marantz (single ended) @CReeDeR mentions. I'm loving the balanced connections through to the V3 Monos because it works in my set up.

Unless you have ground hum issues, there is no real audio benefit to using balanced connections over RCA.
 
Not really any more reliable than any software controlled volume.

The relays are controlled from a microcontroller, and the "state" (volume) has to be remembered when powered off (and not corrupted/lost while powered on). It is no less likely to forget what the volume should be than any other system not consisting of an actual potentiometer.

In an ideal world in this type of system, the volume "value" should be checksummed, and revert to minimum if the checksum doesn't match. I'm not sure if the designers of these types of devices are that careful though.

The best defence from software controlled volume, is to use attenuators on the input to the amp which limit the maximum volume to a safe level for your speakers - even when the volume control is set to max.

My DAC with internal volume control does seem to remember the previous volume, even when unplugged. I haven't tested it after being off for 24 hours or so. My assumption is that it is DAC first, and volume control second so I would never just power on without checking.

The problem with volume controls, especially multiple volume controls in the signal path, is that they can affect the sound quality. They are probably / surely / one of the most influential items in a traditional (not digital) pre-amp.

There are so many amps these days where users can set the volume 'physically' to max, and forget the other control elsewhere in the chain! Never mind any malfunctions!

Let's say there is a power cut, do, for example the Schitt audio Freya pre-amp relay attenuators default to 100%, and rotate to maximum on switch on? I'm pretty sure that if they did, they would require a product call back, or the feedback would be pretty horrendous (verbal written feedback)! There are plenty of users of these pre-amps who have not reported a problem of this nature.
 
Unless you have ground hum issues, there is no real audio benefit to using balanced connections over RCA.
If you check back, the original poster is benefiting from the ability to switch sources - so he is using the RCA connections for one source, and the balanced for the other, and is able to switch by this means.
 
My DAC with internal volume control does seem to remember the previous volume, even when unplugged. I haven't tested it after being off for 24 hours or so. My assumption is that it is DAC first, and volume control second so I would never just power on without checking.

The problem with volume controls, especially multiple volume controls in the signal path, is that they can affect the sound quality. They are probably / surely / one of the most influential items in a traditional (not digital) pre-amp.

There are so many amps these days where users can set the volume 'physically' to max, and forget the other control elsewhere in the chain! Never mind any malfunctions!

Let's say there is a power cut, do, for example the Schitt audio Freya pre-amp relay attenuators default to 100%, and rotate to maximum on switch on? I'm pretty sure that if they did, they would require a product call back, or the feedback would be pretty horrendous (verbal written feedback)! There are plenty of users of these pre-amps who have not reported a problem of this nature.
I agree. The problem has been reported here - but It must be very rare.

I personally have never experienced it across a range of software based volume controls, including three different AVRs, a MiniDSP flex, external sound cards, and all the computers I've ever owned.
 
Unless you have ground hum issues, there is no real audio benefit to using balanced connections over RCA.
Not my experience. It may well have to do with specific equipment, and how each has been implemented in it. In my case, going from an Emotiva ERC-3 CD player (taking advantage of its DAC, so running analog from it) to a Yamaha CX-A5100 pre-pro, the sound via XLR is distinctly superior to RCA . There's no hum issue either way. This is using Blue Jeans cables for RCA cables, compared to no-name XLR.

I note the Fosi mono for instance runs the RCA signals through an extra op-amp to convert to a balanced signal on the way in. If op-amps do color sound at all (no personal opinion on that), that could make a difference. Discussion elsewhere has it that some amp architectures take fuller advantage of a balanced signal input than others. The question might then be double: Does it accept XLR, and if so does it really take advantage of it? This is (per the cute cliche) above my pay grade.
 
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This is (per the cute cliche) above my pay grade
Not above mine though.

No, op amps don't colour the sound - as evidenced by the dozens of op amps the music has already gone through before reaching your amp.
Both the XLR AND RCA inputs measure as transparent. There is no audible difference between them.

Your experience with your CD player is most likely due to the two inputs not being level matched - or just plain old sighted listening perceptive bias - which we are all subject to.
 
Not above mine though.

No, op amps don't colour the sound - as evidenced by the dozens of op amps the music has already gone through before reaching your amp.
Both the XLR AND RCA inputs measure as transparent. There is no audible difference between them.

Your experience with your CD player is most likely due to the two inputs not being level matched - or just plain old sighted listening perceptive bias - which we are all subject to.
Not sure about the "dozens of op amps" argument to support any impact real or imagined changes due to swapping op amps in a buffer or pre-amplifier stage.
A lot of music now is sent directly to an ADC, mixed digitally, and then distributed digitally. The listening done to perform the mix will have opamps in play for sure, but not the mix...
Or my record player to ADC and then back to DAC again. :D
That is not dozens. Just saying.
Some of our favorite recordings from yesteryear had minimum stages between the performance and the recording and sound better for it - are even sought after for it - because they outperform overly processed recordings - perhaps with too many op amps in the signal path - from later years.
There is an argument in that too... Too many op amps in the signal path color or reduce the fidelity of the original recording.
 
Not sure about the "dozens of op amps" argument to support any impact real or imagined changes due to swapping op amps in a buffer or pre-amplifier stage.
A lot of music now is sent directly to an ADC, mixed digitally, and then distributed digitally. The listening done to perform the mix will have opamps in play for sure, but not the mix...
Or my record player to ADC and then back to DAC again. :D
That is not dozens. Just saying.
Some of our favorite recordings from yesteryear had minimum stages between the performance and the recording and sound better for it - are even sought after for it - because they outperform overly processed recordings - perhaps with too many op amps in the signal path - from later years.
There is an argument in that too... Too many op amps in the signal path color or reduce the fidelity of the original recording.
Sure - noise and distortion are cumulative. A thousand stages of inaudible noise and distortion might accumulate to something audible. It won't be "colour" though.

And two or three will not - as evidenced by my second point. Both inputs measure transparent, with the only difference being the expected 6dB resulting from the gain difference.
 
Sure - noise and distortion are cumulative. A thousand stages of inaudible noise and distortion might accumulate to something audible. It won't be "colour" though.

And two or three will not - as evidenced by my second point. Both inputs measure transparent, with the only difference being the expected 6dB resulting from the gain difference.
Yes, or put differently, I think we can hear certain changes in different recording eras. The transistor coming into use in the recording industry recording chain changed the nature of that period of recordings. For lots of reasons, but fundamentally the introduction of the transistor.

I'm not sure it is just the opamp. More likely the opamp and circuit combined - I would not be at all surprised if the higher gain 6db did not sound 'better' in some systems just because of the additional gain.
 
Some of our favorite recordings from yesteryear had minimum stages between the performance and the recording and sound better for it - are even sought after for it - because they outperform overly processed recordings - perhaps with too many op amps in the signal path - from later years.

That's pure conjecture.

There's a million reasons why some recordings sound better than others, but op-amps ain't one of them.

I bet the guy who was a genius at mic placement would disagree with the claim about the lack of op-amps doing all the magic ;)

There is an argument in that too... Too many op amps in the signal path color or reduce the fidelity of the original recording.

Maybe if there's too many really, really badly implemented op-amps in the signal path, but those are rare. Any engineering 101 implementation will have a nearly infinitesimal impact on a line level signal. You'll have to chain a truckload of them to reach an audible effect.

Doesn't help that these things don't add intuitively. It's root-sum-square, meaning that the biggest contributor will make smaller ones even more insignificant.
 
That's pure conjecture.

There's a million reasons why some recordings sound better than others, but op-amps ain't one of them.

I bet the guy who was a genius at mic placement would disagree with the claim about the lack of op-amps doing all the magic ;)



Maybe if there's too many really, really badly implemented op-amps in the signal path, but those are rare. Any engineering 101 implementation will have a nearly infinitesimal impact on a line level signal. You'll have to chain a truckload of them to reach an audible effect.

Doesn't help that these things don't add intuitively. It's root-sum-square, meaning that the biggest contributor will make smaller ones even more insignificant.
Like volume controls ;)

I think there are many engineers who think simple is best. The whole 'digital mixing' phase brought changes, and some horrible digital engineering (loudness).
But that was really my point.
These don't involve dozens of op amps.
Just good engineers! Which is a moot point when it comes to this whole opamp saga.
 
state of the art in audio today have more than enough transparency for what we're able to perceive with our ears

is what measurements shows to us everyday ... we don't need super opamps, thousands of dollars in amplifiers, etc etc

if anyone wants some expensive "audio jewelry" or longer warranty, better reliability, it's ok ... but strictly better sound ... isn't what you will have with a decent enginereed component.
 
No, op amps don't colour the sound - as evidenced by the dozens of op amps the music has already gone through before reaching your amp.
Both the XLR AND RCA inputs measure as transparent. There is no audible difference between them.

Your experience with your CD player is most likely due to the two inputs not being level matched - or just plain old sighted listening perceptive bias - which we are all subject to.
All reproduced sound is colored. All amplifiers sound different. None is truly "transparent." How things measure is at the limit of what exactly the measurement metric is. There is distortion where extra noise is added, which is trivially measurable. But then there's distortion where the original signal is not entirely re-presented in its subtleties. That's very hard to measure when dealing with the complexities of music that's composed of more than a few simple tones. Music is optimized for the full capacities of the human auditory system. Yes, you can use, for instance, MP3 compression which drops many subtleties, and show in A/B tests that most people can't consciously tell the difference. But there's abundant psychological experimental evidence that we're both emotionally and cognitively effected by input which is below the threshold of what we consciously can report. So how we feel in experiencing music depends even on aspects of the musical (re)production that we can't consciously report on discrimination of. And, obviously, some of us can consciously report differences others cannot consciously perceive. My wife can barely tell the difference between a cheap car radio and hi-end hifi, or the difference between a live instrument in the room and one coming over that radio. But, in part from having spent a lot of my life around live instruments, I can. And in decades of running different hifi gear within parameters where it "measures" as highly accurate, it all colors the sound, all leaves out some of the subtleties of the complexities of attack and harmonics -- the clarity of it.
 
All reproduced sound is colored.
There is a whole lot of evidence free claims in that post. That suddenly are no longer above your pay grade. :rolleyes:

How things measure is at the limit of what exactly the measurement metric is
This for example - our measurement gear is way more sensitive than our ears.

That's very hard to measure when dealing with the complexities of music that's composed of more than a few simple tones.
No it's not - a simple null test is pretty straightforward if you have a suitably competent ADC.

But there's abundant psychological experimental evidence
Really?

that we're both emotionally and cognitively effected by input which is below the threshold of what we consciously can report.
Because how then can we tell if someone is emotionally and cognitively affected by something if they are not conscious of it, and hence are unable to tell us about it.

In fact by definition of an emotion - if you are not conscious of it - if you are not feeling it, it doesn't exist.

And in the end - if you are sitting listening to music - completely unaware that the significant changes that you can't hear are somehow impacting your subconscious in a way that you have no conscious knowledge of - but you cant feel it and can't tell anyone about it - not even yourself. Then clearly those changes don't matter.


Honestly this is a new level of audio woo. First measurements don't tell us everything. Blind tests don't work. Our ears are more sensitive than our measurement gear - and so on - to now, unmeasurable stuff in the music somehow affects us in ways that we don't know about, can't hear or feel but that are somehow important to our enjoyment of music. There is no end to this BS.
 
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As for my pay grade, okay I'm a software engineer, not an audio engineer. On the other hand, I've had articles on aspects of human consciousness published in academic journals, and presented at academic conferences. And I've been a serious amateur musician for 55 years. I'm not claiming "ears" are more sensitive, I'm claiming brains are more capable than instrumentation in some aspects of discernment, including aspects which we can't give verbal reports of. There's a abundant neuroscience literature on this.

One typical, and often-repeated type of experiment involves "priming" the mind by flashing a word or image for a briefer time than the subject can consciously see or report on. That word or image will affect their subsequent interpretation and reaction to things they can consciously report on. Another experiment, heavily explored over the last decade, concerns "change blindness": show a picture of a scene, then a brief intermediate distraction, then another picture of the same scene, but with a major change. Most people most of the time cannot see or report on the change -- or even tell that one has been made. This despite that these are large, clearly-visible features in the pictures. (Google "change blindness" for examples.) A/B comparisons of images, despite obviousness when viewed side-by-side, are not necessarily obvious when viewed sequentially. By implication, sequential audio comparisons are also likely to miss major differences, due to being perceived sequentially, rather than side-by-side.

I'd suggest from my own experience of mixing amps and speakers in a common environment that we can tell side-by-side audio differences when simultaneous, especially when prolonged. But I've not conducted formal lab experiments on this. Still, we are more visual than auditory creatures. There's little reason to suggest we should be better at sequential comparison in the auditory realm than we are in the visual.

As for the implication of the reality of unconscious "priming": it has been shown to affect what we subsequently consciously notice, and how we interpret that. Since music is a sequential process, how we're primed in one moment, even unconsciously, can effect what we consciously perceive in subsequent moments.

Look, I know it would be easier from the engineer's standpoint if we could just count on our technology to do everything our brains can. I know some really smart guys who have the fantasy of uploading their minds into supercomputers. But really, our supercomputers are much better at some things than our brains are. There's other stuff we do with our brains that supercomputers can't touch. As a software engineer I respect the hell out of electronic technology. But I also see where it comes up short against our own native capabilities.
 
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But then there's distortion where the original signal is not entirely re-presented in its subtleties. That's very hard to measure when dealing with the complexities of music that's composed of more than a few simple tones.

In reality it's much, much easier to hear distortion of a single tone than it is to hear it in music.

The subtleties and complexities of music are not helping us in any ways, on the contrary. If a piece of gear manages to not mess up a single tone to an audible degree, it's pretty much guaranteed that it won't mess up music audibly either.

IMD might be an issue, but that's not something eluding measurements.

Music is optimized for the full capacities of the human auditory system.

Music is not optimized for anything, IMO. It just happens to fall within the limitations of our biology. Otherwise it wouldn't be enjoyable.
 
Any ideas about this thing? It arrived with my V3 monos.View attachment 382672

Just a hex nut driver with large handle, mine arrived in a separate package, along with the Muses chip (which, btw I didn't ask for :)). I assume you need this tool to replace the chip, should you wish to do so.
 
As for the implication of the reality of unconscious "priming": it has been shown to affect what we subsequently consciously notice, and how we interpret that. Since music is a sequential process, how we're primed in one moment, even unconsciously, can effect what we consciously perceive in subsequent moments.
So - you would be able to tell the difference in a properly controlled blind test.

I suggest you go ahead - perform that test and prove it.
 
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