Fosi v3 Mono - User Impressions | Owner's Thread

[EddNog]

How did you level matched them?
What way?

Fixed test tone and this app:

‎Decibel X:dB Sound Level Meter

‎"Decibel X" is one of very few noise meter apps on the market that has highly reliable, pre-calibrated measurements and supports dBA, dBC. It turns your iOS device into a professional sound level meter, precisely measures the sound pressure level (SPL) all around you. This extremely useful and...

apps.apple.com

-Ed

 

[SMen]

How did you level matched them?
What way?

I use a small hand held db meter set to detect max level. It "reads" to me that you have much more going on than sound level matching and bias.

I think that jumping in so quickly with 'bias' and 'level matching' is almost a form of opinion 'bias' in itself .

But (I must quickly add) - establishing level matching at least takes this out of the equation!

 

[Sokel]

Fixed test tone and this app:

‎Decibel X:dB Sound Level Meter

‎"Decibel X" is one of very few noise meter apps on the market that has highly reliable, pre-calibrated measurements and supports dBA, dBC. It turns your iOS device into a professional sound level meter, precisely measures the sound pressure level (SPL) all around you. This extremely useful and...

apps.apple.com

-Ed

I use a small hand held db meter set to detect max level. It "reads" to me that you have much more going on than sound level matching and bias.

I think that jumping in so quickly with 'bias' and 'level matching' is almost a form of opinion 'bias' in itself .

But (I must quickly add) - establishing level matching at least takes this out of the equation!

Ok,that explains it.
There's no accurate (as it should) level matching other than measuring the voltage at the speaker input with a DMM.

Next time use this way if you want your tests to be any valid.

Edit:In the specific test,ask yourselves why a cheap pot costs $1 and a nice one can go $50-100.
It's that tiny imbalance we're after.

 

[SMen]

Ok,that explains it.
There's no accurate (as it should) level matching other than measuring the voltage at the speaker input with a DMM.

Next time use this way if you want your tests to be any valid.

Edit:In the specific test,ask yourselves why a cheap pot costs $1 and a nice one can go $50-100.
It's that tiny imbalance we're after.

This has really confused me ... we have discussed (or I have pointed out the volume control). These often vary in response at different volumes (am I correct)?
So precisely level matching at one volume might give different results to another volume?

There is so much going on with listening to an amplifier vs another. There is merit surely, in standing back from the process, and asking what other factors might be in play here? I am sure there are more, or there would be nobody bothering to buy V3 monos!

Possibly some quite obvious ones. I've just bought what I hope will be a good quality relay switching device. I'll see. But then I will be comparing volume controls

 

[antcollinet]

This was not a bias issue.

How do you know. "Clear and obvious" is not an answer to this. (Just to be clear, I'm not claiming it definitely wasn't - just that we don't know, in this situation where there aren't clear and obvious explanations for an audible difference)

Try, for example, having the speaker cables attached (accidentally) in reverse terminal order on just one side with the same amps (so one speaker is out of phase), and you’ll notice a clear and obvious problem with how the system sounds.

Of course you will - massive cancellation will occur amongst other things.. But just because some things can and do cause a significant audible difference - doesn't mean that other "clear and obvious" differences we hear can't be bias.

and I am perfectly willing to bet my house that I will be able to tell you which room has matched amps and which room has mismatched amps?

Im sure you are willing. I also have no idea - without you actually trying that test - if you would win the bet.

I find that insinuation insulting.

You shouldn't. Bias is something we all are subject to. It is the way our brains are built - we cannot avoid it. Suggesting it might be at play is not insulting - it is just a statement of fact.

There are a number of perfectly logical and reasonable causes for this, such as slightly out of phase sound because of mismatched circuitry,

Of course - but that wouldn't represent a difference in sound except where you are using both amps together. If only one amp were used there would be no channel phase mismatch. As I pointed out above, another possible explanation would be the V3 load response.

But even with all these possibilities - or speculations, which is what they are - if you don't do a blind test you can't know if there is actually anything there. That is simply down to the nature of our auditory system as I said above.

Try, for example, having the speaker cables attached (accidentally) in reverse terminal order

Back to this - have you checked (for example) that one of the amps isn't inverting the signal where the second does not? Then you'd have a clear reason for an audible difference.

 

[EddNog]

How do you know. "Clear and obvious" is not an answer to this. (Just to be clear, I'm not claiming it definitely wasn't - just that we don't know, in this situation where there aren't clear and obvious explanations for an audible difference)




Of course you will - massive cancellation will occur amongst other things.. But just because some things can and do cause a significant audible difference - doesn't mean that other "clear and obvious" differences we hear can't be bias.


Im sure you are willing. I also have no idea - without you actually trying that test - if you would win the bet.


You shouldn't. Bias is something we all are subject to. It is the way our brains are built - we cannot avoid it. Suggesting it might be at play is not insulting - it is just a statement of fact.


Of course - but that wouldn't represent a difference in sound except where you are using both amps together. If only one amp were used there would be no channel phase mismatch. As I pointed out above, another possible explanation would be the V3 load response.

But even with all these possibilities - or speculations, which is what they are - if you don't do a blind test you can't know if there is actually anything there. That is simply down to the nature of our auditory system as I said above.


Back to this - have you checked (for example) that one of the amps isn't inverting the signal where the second does not? Then you'd have a clear reason for an audible difference.

You continue to be under the impression that I was specifically looking for a difference or for them to be different when in fact it was quite the opposite—I expected them to sound the same. This is why I put the ZA3 on one side and left the V3 Mono in on the opposite side in the first place. I had to get one of the ZA3s warranty repaired for my dad due to a failed RCA connector. I swapped it in after completing the repair (full replacement of amplifier board) to test it, and was surprised to find a huge difference in sound between channels. To further test that there wasn’t just a difference due to difference in gain (which should simply sound like balance being off, which I know the sound of from messing around with the balance plugin on my source unit, which has DSP functionality), I performed that volume level matching as described above using the decibel app from directly in front of the speakers with a fixed tone.

Again, I wasn’t LOOKING for a difference, I was expecting them, in fact, to sound similar enough to run as an unmatched pair after gain matching that I shouldn’t tell the difference, yet here we are. Keep slinging your opinion that I am somehow biased. Sokel at least provided good advice on how my testing may be flawed which is useful, constructive criticism that I can learn from. Yes, in fact, I made sure I had not flipped the speaker cables—that is the first thing that I checked. As for load response, that should be noticeable only at high frequencies. This difference between channels occurs across the frequency spectrum.

Bottom line: I repaired the amp for my dad by replacing the entire board. I wanted to ensure the repair was done right, so I ran this test. I didn’t have the second ZA3 on hand for it, otherwise that is what I have used (it was still in NY with my dad). I expected them to sound almost the same, the result was far from it. In attempting to ensure the repair was good, I level matched the channels using free software on my phone from in front of each speaker by dialing in attenuation with the volume dial on the ZA3. Even when closely approximately matched for volume, I could not get coherent sound left versus right due to the differing amps, and so I double-checked all connections. In the end I considered it best efforts and sent it back to dad. He hooked it back up and is beyond pleased with how his system sounds now thanks to the gift of amps from his son (the pair of ZA3s replace a PS Audio HCA-2 power amplifier). I even included upgraded, Aiyima GAN 48V/10A power supplies for him because his speakers (Magnepan LRS+) are harder to drive than mine.

-Ed

 

[Sokel]

This has really confused me ... we have discussed (or I have pointed out the volume control). These often vary in response at different volumes (am I correct)?
So precisely level matching at one volume might give different results to another volume?

There is so much going on with listening to an amplifier vs another. There is merit surely, in standing back from the process, and asking what other factors might be in play here? I am sure there are more, or there would be nobody bothering to buy V3 monos!

Possibly some quite obvious ones. I've just bought what I hope will be a good quality relay switching device. I'll see. But then I will be comparing volume controls

Cheap pots can have channel imbalance (even not so cheap can have).
The more you attenuate,the more imbalance can occur.But that's not our subject here.

Our subject is comparing amps,either as mono or stereo.
The No1,most significant rule is level matching them as much as possible,within single digit mV if possible.

And that can only happen with a test tone (say 60Hz so may won't need a true RMS DMM) and the DMM in AC scale measuring directly at the input of the speaker.
That's the only way.

That in addition to what @antcollinet said.

 

[AaronJ]

 

[antcollinet]

You continue to be under the impression that I was specifically looking for a difference or for them to be different

No, I wasn't. Cognitive biases don't necessarily occur based on our conscious beliefs or expectations. It is quite possible for you to expect no difference, for there to BE no difference, but still percieve a difference due to cognitive biases. They are a subconscious process acting on our built in subconscious biases. And by "bias" don't think of "prejudice". Think of it more analogous to biasing a transistor - a shift in your perception based on the way your brain has been wired by a lifetime of prior experiences.

Again - you may well be hearing a real difference. But without a properly controlled comparison (blind and accurately level matched) we really can't know - no matter how clear and obvious your perception of the difference is.

 

[EddNog]

No, I wasn't. Cognitive biases don't necessarily occur based on our conscious beliefs or expectations. It is quite possible for you to expect no difference, for there to BE no difference, but still percieve a difference due to cognitive biases. They are a subconscious process acting on our built in subconscious biases. And by "bias" don't think of "prejudice". Think of it more analogous to biasing a transistor - a shift in your perception based on the way your brain has been wired by a lifetime of prior experiences.

Again - you may well be hearing a real difference. But without a properly controlled comparison (blind and accurately level matched) we really can't know - no matter how clear and obvious your perception of the difference is.

Clearly then I have nothing further to contribute here since I don’t maintain a scientific lab or procedures that meet ASR standards for testing. I’ll just keep my knowledge to myself from here on out and lurk rather than trying to contribute. Have a nice rest of your day.

-Ed

 

[antcollinet]

Clearly then I have nothing further to contribute here since I don’t maintain a scientific lab or procedures that meet ASR standards for testing. I’ll just keep my knowledge to myself from here on out and lurk rather than trying to contribute. Have a nice rest of your day.

-Ed

That of course is up to you.

However it is possible to have many discussions here without any form of test lab - or without carrying out any blind tests at all.

On the other hand, I never make any pronouncements about what I hear as though my perceptions are universal truth either.

Have a nice day also - and I hope you continue to participate.

 

[SMen]

Clearly then I have nothing further to contribute here since I don’t maintain a scientific lab or procedures that meet ASR standards for testing. I’ll just keep my knowledge to myself from here on out and lurk rather than trying to contribute. Have a nice rest of your day.

-Ed

It is much more interesting with you here @EddNog ...

There is a lot that is interesting in your post. And indeed a spot of humanity. Much needed.

As with everything, proposed methodologies can go too far if they become 'the only' way. I think that in switching, the brain fills in previous with next. There is a lot the brain fills in. Switching (for me) would only show quite obvious frequency response issues, and a preference for volume (higher).

There is an argument for longer listening periods. I find the db meter useful at my sitting position, and music I know really well. Then I keep what I prefer. What makes me happier and more involved.

I suspect that if you preferred your ZA3s your father would have been ecstatic with the monos!

And how much bias is there in 'this measures well so, wow, it sounds amazing' ... kind of thing. I think there are more obvious (to be discovered) factors at play in your description than bias, or levels. But that is just my experience in, for example, comparing an Aiyima A07 to an A08 to a BRZ3255 balanced, and soon the monos. When they arrive.

And, I suspect passive or active devices further up the chain like volume controls are in fact a part of the mix. Anyway!

 

[jvdburgt]

Can we go back to discussing rolling op-amps? This shit got way too real for me

 

[Basilderat]

Clearly then I have nothing further to contribute here since I don’t maintain a scientific lab or procedures that meet ASR standards for testing. I’ll just keep my knowledge to myself from here on out and lurk rather than trying to contribute. Have a nice rest of your day.

-Ed

I think your testing was perfectly reasonable. You've provided a good scientific methodology for basing an opinion of delta in perceived sound from the two devices. I'm hoping the delta equates to a better performance (more pleasing sound) out of the V3 Monos! If I could be bothered I would run the same test with my Topping PA7 and one of the V3 Mono's when they arrive. In reality, I'm just going to plug them in and hope they sound as good or better. nb. I have three music setups but can't afford three PA7's.

 

[Bonza]

That of course is up to you.

However it is possible to have many discussions here without any form of test lab - or without carrying out any blind tests at all.

On the other hand, I never make any pronouncements about what I hear as though my perceptions are universal truth either.

Have a nice day also - and I hope you continue to participate.

“A wise old owl sat on an oak; The more he saw the less he spoke; The less he spoke the more he heard; Why aren't we like that wise old bird?

 

[NTK]

I think your testing was perfectly reasonable. You've provided a good scientific methodology for basing an opinion of delta in perceived sound from the two devices. I'm hoping the delta equates to a better performance (more pleasing sound) out of the V3 Monos! If I could be bothered I would run the same test with my Topping PA7 and one of the V3 Mono's when they arrive. In reality, I'm just going to plug them in and hope they sound as good or better. nb. I have three music setups but can't afford three PA7's.

May sound reasonable to the uninitiated, but in reality it is proven to be unreliable.

The Dishonesty of Sighted Listening Tests

An ongoing controversy within the high-end audio community is the efficacy of blind versus sighted audio product listening tests. In a blind...

seanolive.blogspot.com

 

[SMen]

May sound reasonable to the uninitiated, but in reality it is proven to be unreliable.

The Dishonesty of Sighted Listening Tests

An ongoing controversy within the high-end audio community is the efficacy of blind versus sighted audio product listening tests. In a blind...

seanolive.blogspot.com

Yes. It is possible with the monos to be sighted but not know which is playing, if anyone wants to try op amps. Speakers are a bit more problematic.

I am just wondering if each mono could be be simultaneously connected to both speakers, and then someone (a relative or friend) could switch between each mono block?

As a small observation, I am guessing that pretty much everyone on these 3255 threads have, on the basis of their listening, heard a very high quality sound from a very inexpensive ampifier ... and they have not shown bias along the lines of 'something being so cheap cannot sound good'.

They did not need to blind test, nor did they need to measure ... if they were at all like me they just said 'wow that sounds good for spending peanuts' ...

just saying. Sometimes things really are obvious.

But I am all for blind testing and challenging any bias I may have, and remaining open minded ... same goes for what others hear / don't hear.

 

[P1NBA11ER]

You continue to be under the impression that I was specifically looking for a difference or for them to be different when in fact it was quite the opposite—I expected them to sound the same. This is why I put the ZA3 on one side and left the V3 Mono in on the opposite side in the first place. I had to get one of the ZA3s warranty repaired for my dad due to a failed RCA connector. I swapped it in after completing the repair (full replacement of amplifier board) to test it, and was surprised to find a huge difference in sound between channels. To further test that there wasn’t just a difference due to difference in gain (which should simply sound like balance being off, which I know the sound of from messing around with the balance plugin on my source unit, which has DSP functionality), I performed that volume level matching as described above using the decibel app from directly in front of the speakers with a fixed tone.

Again, I wasn’t LOOKING for a difference, I was expecting them, in fact, to sound similar enough to run as an unmatched pair after gain matching that I shouldn’t tell the difference, yet here we are. Keep slinging your opinion that I am somehow biased. Sokel at least provided good advice on how my testing may be flawed which is useful, constructive criticism that I can learn from. Yes, in fact, I made sure I had not flipped the speaker cables—that is the first thing that I checked. As for load response, that should be noticeable only at high frequencies. This difference between channels occurs across the frequency spectrum.

Bottom line: I repaired the amp for my dad by replacing the entire board. I wanted to ensure the repair was done right, so I ran this test. I didn’t have the second ZA3 on hand for it, otherwise that is what I have used (it was still in NY with my dad). I expected them to sound almost the same, the result was far from it. In attempting to ensure the repair was good, I level matched the channels using free software on my phone from in front of each speaker by dialing in attenuation with the volume dial on the ZA3. Even when closely approximately matched for volume, I could not get coherent sound left versus right due to the differing amps, and so I double-checked all connections. In the end I considered it best efforts and sent it back to dad. He hooked it back up and is beyond pleased with how his system sounds now thanks to the gift of amps from his son (the pair of ZA3s replace a PS Audio HCA-2 power amplifier). I even included upgraded, Aiyima GAN 48V/10A power supplies for him because his speakers (Magnepan LRS+) are harder to drive than mine.

-Ed

I’m curious, did you try swapping the cables backwards on purpose? I wonder if the ZA3 could be out of phase from the V3 and while I could have missed this, I didn’t see it mentioned reading back.

 

[EddNog]

@P1NBA11ER No, I did not try that. It does not occur to me to run things out of the norm. Said unit has also ceased to function again for my dad and I don’t have the unit back yet to diagnose.

Any more questions about that ZA3 should be moved to the ZA3 review/discussion thread and not clutter this V3 Mono thread.

-Ed

 

[SMen]

You continue to be under the impression that I was specifically looking for a difference or for them to be different when in fact it was quite the opposite—I expected them to sound the same. This is why I put the ZA3 on one side and left the V3 Mono in on the opposite side in the first place. I had to get one of the ZA3s warranty repaired for my dad due to a failed RCA connector. I swapped it in after completing the repair (full replacement of amplifier board) to test it, and was surprised to find a huge difference in sound between channels. To further test that there wasn’t just a difference due to difference in gain (which should simply sound like balance being off, which I know the sound of from messing around with the balance plugin on my source unit, which has DSP functionality), I performed that volume level matching as described above using the decibel app from directly in front of the speakers with a fixed tone.

Again, I wasn’t LOOKING for a difference, I was expecting them, in fact, to sound similar enough to run as an unmatched pair after gain matching that I shouldn’t tell the difference, yet here we are. Keep slinging your opinion that I am somehow biased. Sokel at least provided good advice on how my testing may be flawed which is useful, constructive criticism that I can learn from. Yes, in fact, I made sure I had not flipped the speaker cables—that is the first thing that I checked. As for load response, that should be noticeable only at high frequencies. This difference between channels occurs across the frequency spectrum.

Bottom line: I repaired the amp for my dad by replacing the entire board. I wanted to ensure the repair was done right, so I ran this test. I didn’t have the second ZA3 on hand for it, otherwise that is what I have used (it was still in NY with my dad). I expected them to sound almost the same, the result was far from it. In attempting to ensure the repair was good, I level matched the channels using free software on my phone from in front of each speaker by dialing in attenuation with the volume dial on the ZA3. Even when closely approximately matched for volume, I could not get coherent sound left versus right due to the differing amps, and so I double-checked all connections. In the end I considered it best efforts and sent it back to dad. He hooked it back up and is beyond pleased with how his system sounds now thanks to the gift of amps from his son (the pair of ZA3s replace a PS Audio HCA-2 power amplifier). I even included upgraded, Aiyima GAN 48V/10A power supplies for him because his speakers (Magnepan LRS+) are harder to drive than mine.

-Ed

I have to say that the more I read this the more perfectly reasonable this post seems to me (not the explanation of the problem).

I mean, anyone who has used dual volume controls, or a balance control knows what it is like to pan the sound from left to right.

You don't need level matching for that! (the whole point of panning is having different levels).

Nor do you need to reference or beware of auditory bias!

Nor do you need to blind test!

@P1NBA11ER No, I did not try that. It does not occur to me to run things out of the norm. Said unit has also ceased to function again for my dad and I don’t have the unit back yet to diagnose.

Any more questions about that ZA3 should be moved to the ZA3 review/discussion thread and not clutter this V3 Mono thread.

-Ed

I think quite accidentally you have highlighted the ridiculousness of some of the stock answers we get on this forum sometimes. It seems there might have been a problem with the unit.

Maybe back to user experiences with the monos ... quite agree.