Sparkos SS3602 Opamp Rolling In Fosi P4

[pma]

That low level junk I circled in red

This is typical, and says why op-amps should not be swapped without measurements. Bypass capacitors, JFET vs. BJT, PCB design, case material and EMI shielding - everything makes the difference at the very low level.

 

[MaxwellsEq]

Yes......and that is why all the questions.
New Record Day has promoted this video with sound examples, but can you hear the differences?
The music files are ready for download too

I'm not wasting my time.

Please start using your brain for thinking critically, rather than randomly bouncing around.

Who benefits if the files sound different? Who does not benefit if the files sound the same?

 

[pma]

I'm planning on writing up a test of this preamp, with some details on actual performance difference between opamps, and the differences when changing the surrounding circuit values.

I did the homework on op-amp susceptibility to surrounding EMI several times, since 2007. I use a circuit with noise gain 86 dB, to emphasize the differences. Below some results from the year 2020.

 

[antcollinet]

Funny thing is this is a clever answer because it is not totally wrong, as usual. If you compare stuff with very significant differences, like a lot of distortion or changed stereo width (mono in the extreme case), then a few dB of volume difference don't mask the differences.

Obviously, the smaller the differences, the larger the need to have matched levels for a meaningful initial comparison followed by successful ABX or AB/HR etc. However, IME once one has nailed the difference in knowing what exactly to listen for in a successful DBT then volume levels again have some wiggle room, you still identify the artifacts/differences (of course with different DBT protocol than simple ABX).

You are looking at it the wrong way around. The issue isn't volume changes masking differences that are real.

The problem is, small level differences can create a perception of changed sound/timbral quality due to the nature of the equal loudness curves of human hearing. Furthermore, in a blind test, they can create a 'tell' which 'unblinds' the test.

 

[KSTR]

The problem is, small level differences can create a perception of changed sound/timbral quality due to the nature of the equal loudness curves of human hearing. Furthermore, in a blind test, they can create a 'tell' which 'unblinds' the test.

As mentioned, this depends on the blind test's design. In an ABX of course any level difference will be a tell for trivial difference (unless level diffences is the subject of the test). This is why ABX is not necessarily the best protocol for audio tests.

But if the test description (extreme case) "can you tell apart which file is mono and which is stereo" then the result of this test does not depend on level at all, obviously. With more subtle differences then different levels start to be a problem, of course. And the moment we are trying to judge minute changes in soundstage etc then equal levels are really important.

 

[M.C. Logan]

Sorry, but you're wrong.

I.e., "the distortion of B is four times lower than the distortion of A" would usually be supposed to mean, that the distortion of B equals one fourth (= one quarter or respectively 25 %) of the distortion of A. Whereas "the distortion of B is one quarter lower than the distortion of A" would rather mean, that the distortion of B equals the distortion of A minus one quarter of the distortion of A, hence equalling three quarters (or respectively 75 %) of the distortion of A.

Where it gets more difficult: "The distortion of B is four times higher than the distortion of A." Because that's not quite the same as "the distortion of B is four times as high as the distortion of A". So while the latter would simply mean "distortion of B = 4 x distortion of A", the former might rather mean "distortion of B = distortion of A + 4 x distortion of A = 5 x distortion of A".

I'd agree with you, however, that there's a bit of a "logic break" there - 'cause while "is four times lower than" would equal "is four times as low as", "is four times higher than" might rather not equal "is four times as high as".

Greetings from Munich!

Manfred / lini

Er, I never said on quarter lower, I said one quarter, as in: one quarter of x = x/4.
Otherwise you are correct, which is why for clarity and accuracy we should always use
'a is y/z of b' for smaller
and
'a is x times as high/large/etc. as b'
Best Regards, M

 

[pkane]

Looks like this guy has some comments about Fosi P4 + Sparkos
when it comes to sound and maybe want to try out if I can hear
some differences in my own system. Comments about the Fosi ZD3
+ Burson is also tempting to try out. I am curious if soundstage
and imaging can make a difference.

This is as far as I got and won't go any further:

 

[oleg87]

Looks like this guy has some comments about Fosi P4 + Sparkos
when it comes to sound and maybe want to try out if I can hear
some differences in my own system. Comments about the Fosi ZD3
+ Burson is also tempting to try out. I am curious if soundstage
and imaging can make a difference.

I don't know how many times this needs to be repeated, but uncontrolled listening tests are not fit for gauging such differences.
I don't find the contents of some random youtuber's imagination very interesting.

 

[Ropeburn]

At least the clickbaity thumbnail title ends up being involuntarily honest. More nonsense indeed.

TL;DW: The usual subjectivity from a heavily affiliated YouTuber with dozens of buying links in the description. A lot of talk and no substance. Don't bother.

 

[DavidM1]

Hifi myths are truly fascinating. Interconnects, power cables, power hygiene, extra clocking, op amps…

It’s all in the realm of shared stories - rumours, half truths, conspiracy theories, superstitions, quackery, religion (not yours, other people’s).

And yet, when it comes down to it, we are pretty good at trusting the science when flying between continents or in an operating theatre watching a stent being inserted in a coronary artery.

I love the fact that my cheap Chinese dac and amp are part of the age old fight against ignorance. lol.

 

[wwenze]

The most well-paying "sciences" are those that you cannot verify the effects of

The evidence-based pass-or-fail science is sold to the lowest bidder

 

[antcollinet]

I am curious if soundstage
and imaging can make a difference.

Have you not been listening?

It can't


Also- please don't post such nonsesnse youtube vids:

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[Jimster480]

Looks like this guy has some comments about Fosi P4 + Sparkos
when it comes to sound and maybe want to try out if I can hear
some differences in my own system. Comments about the Fosi ZD3
+ Burson is also tempting to try out. I am curious if soundstage
and imaging can make a difference.

Soundstage and Imaging wouldn't change. Those things are affected by the overall performance of your amp, not the op-amps.
Neither Burson nor Sparkos is really cleaner than the NE5532.... so your best bet for a roll would be a LM4562, but that would also not change imaging...

 

[Flageborg]

Thank you guys.
A lot of comments out there, but I am very pleased with
my Fosi X5 which was iniated by review on this site.
The Fosi P4 will consider to buy and add extra opamp
just for curiosity to find out what this fuzz is all about.
Many people are complaining about the sound quality
which is presented by Youtube and maybe my own
system is even worse to detect any sound difference.

 

[Mnyb]

Thank you guys.
A lot of comments out there, but I am very pleased with
my Fosi X5 which was iniated by review on this site.
The Fosi P4 will consider to buy and add extra opamp
just for curiosity to find out what this fuzz is all about.
Many people are complaining about the sound quality
which is presented by Youtube and maybe my own
system is even worse to detect any sound difference.

There at least >2 gothchas with this kind of video .

* These kind of differences are so subtle that they would not survive being recorded in room with microphones and then go trough YouTube compression algorithms .

* If there are actual differences that can be heard in the video something is very wrong intentionally or unintentionally .

All the usual gotchas about sighted no blind non level matched comparisons of subtle differences also applies .

It's very very tempting to use YouTube videos as proxies to "hear" how a component might sound . But in most cases it simply can not work . But as a large group of viewers of such videos really really want this to be true , The content creators obliges as this gives them clicks and ad revenue .

If it's electronics just forget about using YouTube videos to compare anything . Especially DAC's then you know the person posting the video probably is incompetent , as in a proper test you cant hear differences in person anyway ( provided reasonably sane DAC design ). You can then unsub that reviewer forever.

It may be videos that "works" depending on what to compare ,but its very specific what you can do and how useful it is out of context .

 

[T&T]

I used to own a collection of 12ax7 all brands, Telefunken, ect, after I discovered the opamps world, I sold all to Japanese guy.

Now, I own a Geshelli akm4499 and 2 Fosi ZA3 which I used in Mono (sold my V3 monos too dull), so I get both fosi amplifier on the bare circuit and I star rolling opamps only in 1 amplifier them decide which one sounds better
worse, similar or bad, after listening same song over and over, raising the volume from one to the other amplifier, I have been doing this for 8 years.

I change the opamps on the Geshelli and the Amplifier, total of 6 opamps changed, most of the test done here are base in 1 opamps per channel so do the numbers when you change 3 opmaps per Channel.

Them if all opamps are the same will be pointless from companies to make different opmaps, no audio manufacturer company would buy since all are the same. Unfortunately as you get old we lose more than the hearing.

 

[DavidM1]

* These kind of differences are so subtle that they would not survive being recorded in room with microphones and then go trough YouTube compression algorithms .

I would suggest reading the review at the beginning of this thread. There are no audible differences.

 

[Mnyb]

I would suggest reading the review at the beginning of this thread. There are no audible differences.

yes i know , I just stated in general your need a gross error to get trough an microphone recording on youtube

 

[tileiar]

Hello Amir, thank you very much for your very interesting tests and measurements on the subject of op amp rolling! I am honestly surprised that the discrete op amps perform so well. It's not to bash discrete op amps, but the complexity, density and precision that modern chip production processes can achieve are much more advanced than discrete circuits can be.

Nonetheless, I'm not entirely happy with your comment that the performance of op amps is largely equalised by the feedback loop. That may be true for some parameters. But I think it's more about the overall circuit design of the particular audio device and the specific functional block for which the op amp is used. For example, the power supply rejection ratio (psrr) is not so relevant if you have a very well designed (clean) power supply.

If you want to go even deeper down the rabbit hole, there may be other tests you can use to find measurable differences. Your research shows that these will not be audible (at least with reasonable settings).

Which can also be measured:

• DC offset / DC level at the output
• common mode rejection rate of the input (imported noise by cabling)
• noice floor especially at very low frequencies (< 100Hz)
• input resistance: possible impacts on level, frequency response and dc offset when sourcing from a source with high output resistance (100+ Ohm)
• output performance on difficult loads (600 Ohm) and/or on high output levels (power supply headroom, slew rate, max power)
• power consumption and as consequence heating based performance degradations (eg. drift)

Thank you and best regards, Armin

 

[SIY]

Which can also be measured:

• DC offset / DC level at the output
• common mode rejection rate of the input (imported noise by cabling)
• noice floor especially at very low frequencies (< 100Hz)
• input resistance: possible impacts on level, frequency response and dc offset when sourcing from a source with high output resistance (100+ Ohm)
• output performance on difficult loads (600 Ohm) and/or on high output levels (power supply headroom, slew rate, max power)
• power consumption and as consequence heating based performance degradations (eg. drift)

Do you understand that there's an output stage between the op-amp and the output?

Noise data were presented. Did you miss those? Determined by the output stage, of course.