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

nishamn27

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Gonna separate this out, because you might have liked my previous post before I added it:


Without properly controlled and blind listening test you have no idea if it diid or not.
My friend. I don't know how to further more explain this. Let it be like you said it would be.
I have a request, if people like playing with opamps, let them.
You are denying something I told which you havnt tried doing.
I told you in the initial posts itself that I have two units, I tried my best to level match em and did comparisons.
Anyway, Leave it.
 

nishamn27

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Me neither. But the risk of it being caused by expectation bias is large, to say the least.
I just posted my opinion about it. If anybody seems interested to try it out, they can do.
When it comes to sound, I guess a small difference makes a big deal after a while of trying out different things.
I definitely had a difference in swapping opa1656 with opa1612. You are welcome to give a try if you are interested.
 

Killingbeans

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You are welcome to give a try if you are interested.

Why? I already know that cognitive bias can mess with my perception. Why would I be interested in reaching faulty conclusions on purpose?

If I wanted that, I'd much rather just go to a magic show :)
 

antcollinet

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Hehe
There's nothing to leave from my side I believe
Didn't think you would. And as long as you continue to promote misinformation, I'll continue to push back.


I changed the opamp and got a difference in sound. May it be huge or small.

You perceived a difference in sound. The "level matched" test you described, you have already been informed was significantly flawed to the extent of being meaningless.

Therefore neither we, nor you, know if that perception actually came from the soundwaves reaching your ears, or if it was modified by your subconscious brain by the "bias" systems we all have. The much more likely case is the latter.

I'm not trying to prevent anyone playing with op amps. If you are having fun - have at it. But don't you also want to understand if what you are percieving is scientifically valid? Especially when the science/engineering says the sound characteristics you say you heard are quite unlikely to the point of impossibility. Surely that is why you are posting at a science focussed forum?

If so, it is not much more effort over changing the op amps, to set up to do a properly controlled blind test.

If you're not interested in that, then don't be surprised when people are similarly not particularly interested in hearing about unvalidated "impressions"
 

nishamn27

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Why? I already know that cognitive bias can mess with my perception. Why would I be interested in reaching faulty conclusions on purpose?

If I wanted that, I'd much rather just go to a magic show :)
Good luck with the magic show! :D

Was jus kidding. If you are not interested, leave it. Problem solved
 

nishamn27

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Didn't think you would. And as long as you continue to promote misinformation, I'll continue to push back.




You perceived a difference in sound. The "level matched" test you described, you have already been informed was significantly flawed to the extent of being meaningless.

Therefore neither we, nor you, know if that perception actually came from the soundwaves reaching your ears, or if it was modified by your subconscious brain by the "bias" systems we all have. The much more likely case is the latter.

I'm not trying to prevent anyone playing with op amps. If you are having fun - have at it. But don't you also want to understand if what you are percieving is scientifically valid? Especially when the science/engineering says the sound characteristics you say you heard are quite unlikely to the point of impossibility. Surely that is why you are posting at a science focussed forum?

If so, it is not much more effort over changing the op amps, to set up to do a properly controlled blind test.

If you're not interested in that, then don't be surprised when people are similarly not particularly interested in hearing about unvalidated "impressions"
Different opamps perform different with different circuits.
Rolling opamps will make a difference as long as the circuit remains constant.
I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different. And i donot believe it's subjective.
Like you said, it may or may not make the measurments worse.

If The same engineers who made this amp itself claims that different opamp could sound different in it, what is there to prove

I believe you have gone through fosi's YouTube page.
Why don't you ask them to prove it scientifically?
 

nishamn27

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Different opamps perform different with different circuits.
Rolling opamps will make a difference as long as the circuit remains constant.
I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different. And i donot believe it's subjective.
Like you said, it may or may not make the measurments worse.

If The same engineers who made this amp itself claims that different opamp could sound different in it, what is there to prove

I believe you have gone through fosi's YouTube page.
Why don't you ask them to prove it scientifically?
Actually, all that matters for getting your proof is get a bunch of opamps, swap them all. And do a real "listening" test
Your time spent on it won't be wasted. Trust me

Weather it is good or bad, it definitely makes a difference in what you hear
 

Killingbeans

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Problem solved

Not really. The main problem is that you, to put it bluntly, seem to be promoting alchemy as a valid substitute for scientific rigor.

And i donot believe it's subjective.

The key word here is 'believe'. The odds of it holding up to scrutiny are very slim.
 

antcollinet

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Like you said, it may or may not make the measurments worse.
That is not the point of what I said.

Why don't you ask them to prove it scientifically?
Because they are not here on this forum making bullshit arguments.

I believe you have gone through fosi's YouTube page.
Why do you believe that. I don't think I've seen a FOSI youtube vid. I rarely put much faith in manufacturers marketing material.

If The same engineers who made this amp itself claims that different opamp could sound different in it, what is there to prove
Becase it is marketing. They are there to sell a product. Manufacturers make all sorts of vague - or even outright false claims about their products. See every single high end cable manufacturer.

I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different. And i donot believe it's subjective.
We are not about beliefs here, we are about facts, measurements, tests. What can be supported by evidence, or what cannot.
 
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BDWoody

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I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different.

Ok, then there is no evidence that's the case. Since we are just going nowhere here, I'm going to give you a temporary break from this thread.

There is a lot of info on the site that may help you to either put together a test that does more than add to the pile of unsupported anecdote, or have a look through the dozen or more op-amp rolling threads to get a better idea of what is actually happening, but otherwise there is no real point going on with this.
 

fpitas

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who you guys just simply dont ship "upgraded" V3 to Amir and he tests it, all discussions would be over.
I think that would end the fun. Or something.
 
OP
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bgravato

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I ended up buying the Fosi V3 (and keeping it). I didn't try any other op-amps, since the ones that came from stock worked just fine...

I can't tell any differences in sound between the Fosi V3 with original op-amps vs a pretty decent class AB vintage amp I have, so there's no point in trying different op-amps to me.
 
D

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Different opamps perform different with different circuits.
Rolling opamps will make a difference as long as the circuit remains constant.
I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different. And i donot believe it's subjective.
Like you said, it may or may not make the measurments worse.

If The same engineers who made this amp itself claims that different opamp could sound different in it, what is there to prove

I believe you have gone through fosi's YouTube page.
Why don't you ask them to prove it scientifically?

There are not many right things in this post..
 

solderdude

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Different opamps perform different with different circuits.
Yep, in this case is just a buffer so the performance in the audible range means the only difference could be noise floor and maybe distortion.
Distortion of the power amp itself is higher, noise floor of the power amp itself is higher, 'tone' arguably won't be changed, the bandwidth is (severely) limited by the power amp itself.
Even a TL071 will have a bandwidth greatly exceeding that of the power amp.

Using opamps to directly drive loads they aren't designed for (C'Moy amps driving low impedance headphones) will indeed easily lead to audible (and extremely measurable) differences. That application (and high gain pre-amp circuits) is where the 'op-amp rolling' comes from. Not an input buffer, that does not load the op-amp in a 'nasty' way, for a (not that great performing) class-D chip.

Rolling opamps will make a difference as long as the circuit remains constant.
It is the circuit that determines the bandwidth and gain within the audible band. In this case it is a buffer or just a few x gain.
So in the end the opamp will either influence the noise floor and distortion. The latter is dwarfed by that of the power amp.
Were the opamp used in a circuit where high gain, high input impedance, wide bandwidth, ultra low distortion all matter (think instrumentation amp, sensor pre-amp, phono or mic pre-amp) then yes there will be a substantial difference that can certainly determine performance and reach audible levels.

Are you an audio electronics designer ? Have you measured the actual performance (signal fidelity) in all aspects ? Do you have test equipments for that and the chops ? Did you do 'blind', level matched and statistical relevant testing ? Do you even know how to do that ?

I did not mention anywhere that it would improve the measurments or performance of the amplifier. It just makes it sound different.
So.... measurements (and thus performance) does not improve (change) but the sound changes ?
The 'sound' is thus not determined by signal fidelity but something that cannot be measured but 'changes' it somehow ?

And i donot believe it's subjective.
It has nothing to do with subjective... it has everything to do with knowing what chip is in the circuit.

Like you said, it may or may not make the measurments worse.
But.... you just said "I did not mention anywhere that it would improve the measurments or performance of the amplifier"
What is it ?

If The same engineers who made this amp itself claims that different opamp could sound different in it, what is there to prove
Well the engineers have to prove it. Providing a DIL socket in a circuit and making a claim that it is specifically for opamp rolling is not any proof it is a marketing trick for an extremely cheap (vs power output) toy.

I believe you have gone through fosi's YouTube page.
I didn't... it is there for reasons to boost sales.

Why don't you ask them to prove it scientifically?
It is you who makes the claim. Fosi just handed people a way for people to 'roll-away' because it is fun. People will come back to brands that promote and offer 'DIL sockets' in their amps.
 
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Killingbeans

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So.... measurements (and thus performance) does not improve (change) but the sound changes ?
The 'sound' is thus not determined by signal fidelity but something that cannot be measured but 'changes' it somehow ?
But.... you just said "I did not mention anywhere that it would improve the measurments or performance of the amplifier"
What is is ?

The way I understood it, he's saying that changes in sound would be linked to significant worsening of objective performance.

Essentially we're back to 'circuit bending'. That would be fine in my book if only people would admit it (and it wasn't placebo). "I enjoy spending time f¤¤king up the buffer in my amp, just to see how it sounds". But no... it's always: "I swapped in this huge super expensive discrete op-amp. Had to drill a hole in the enclosure, to make it fit. It lifted all the veils and made the microplankton multiply like crazy!" :facepalm:
 
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