Op-amp Rolling Using Sparkos on Fosi V3 Mono

[Caliban]

Noob question…

Some are reporting changes in the sound volume when rolling opamps. I was under the impression that the external components—what is not “rolled”—were defining the operating conditions/range of the opamp. Hence the no audible difference if these components are the same.

A change in volume is reasonably easy to hear. But is it also an indication that’s there could be other differences (some being audible) due to the way the opamp is used in the circuit?

I may be guessing here, but in my case, i suspect the 5532 puts a "heavier load" on the input connections compared to 4558. If there are resistors in series
of the OP-amp inputs (outside of feedback loop) it can have an influence. But that is just a guess.

 

[Esprit]

I predict that “Those Graphs” will show up soon and talk to all of us…and talk and talk.

The net is chattering…

 

[JSmith]

get checked

Give the off topic videos a rest;

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[Hipster Doofus]

Not to be too technical here but the best part of the hard work and hours it must of taken to do this review twice was Amirm taking the time to find the Discount Coupon….

$$$$$$$. WAY TO SHOP $$$$$$$$

 

[CedarX]

Another noob question…

This is from a Sparkos opamp datasheet:

Is it a case where they may have a point when their opamp is used in, say the final stage of an open-loop, low-power IEM amplifier, but it has absolutely no bearing in the most common closed-loop circuitry?

In other words, is Sparkos and other IOEMs “milking” a possibly legit., but seldom found, benefit to justify the rolling practice everywhere?

 

[Herbert Shooler]

Exquisite genius Amir,another atom bomb of truth to detonate in the vacuum heads of these Utubers who claim to hallucinate, sorry hear a difference!

 

[gwing]

Another noob question…

This is from a Sparkos opamp datasheet:
View attachment 441301
Is it a case where they may have a point when their opamp is used in, say the final stage of an open-loop, low-power IEM amplifier, but it has absolutely no bearing in the most common closed-loop circuitry?

In other words, is Sparkos and other IOEMs “milking” a possibly legit., but seldom found, benefit to justify the rolling practice everywhere?

It's simpler than that . Provided the opamp can provide the gain required by the circuit it is put in then there is no point in putting in a different opamp with greater open loop gain.

If you were to design a different amplifier that used higher levels of feedback therefore requiring an opamp with greater gain it would be a different matter, you should use an opamp that matched the requirements of the new amplifier and the opamps in the old amplifier might not be optimal.

 

[bigLP]

Thank you for this review.
Power cords in the dustbin
Speaker cables in the dustbin
Vibrating things in listening rooms dustbin
Power conditioners dustbin
Dustbin getting pretty full
On to Loch Ness

is it Ned's Atomic Dustbin?

 

[DWPress]

As an older audiohead, I will confess to buying into "magic" tweaks for many years and there's probably a lot of us who've been looking for the perfect sound for 40 years who have as well. ASR is a cure for ignorance but, like a vaccine, sometimes a little dose isn't enough.

 

[holbob]

I think you should do equipment racks that claim to improve the soundstage next.

Maybe do a 50 rack mana acoustics one? That'll keep you busy for a month setting it up!

 

[solderdude]

Is it a case where they may have a point when their opamp is used in, say the final stage of an open-loop, low-power IEM amplifier, but it has absolutely no bearing in the most common closed-loop circuitry?

In cases where an op-amp has to drive low impedance headphones directly, and that op-amp is not designed specifically for that purpose, circuits like the well known C'Moy amps for instance or 'headphone output stages' using regular op-amps without external output devices then swapping suitable op-amps (not all op-amps are suitable) by some discrete ones certainly can have (even audible) benefits.
In that case the reason is the output current limit(er) behavior.

When one does not know what one is doing op-amp rolling is a silly endeavor as anything can happen between no sound, blown up circuits, oscillations, less performance via 'irrelevant differences' to 'slightly better measurements.
This depends on the circuit it is in.

But yes, in some cases the discrete ones could have better performance than some DIP or SMD op-amps. In other cases the discrete ones may give 'lesser' performance.

Key here is... knowledge and appropriate measurement equipment is highly recommended if the goal is to improve performance.

 

[M.C. Logan]

Thank you for this review.
Power cords in the dustbin
Speaker cables in the dustbin
Vibrating things in listening rooms dustbin
Power conditioners dustbin
Dustbin getting pretty full
On to Loch Ness

Hmm, there is one case for speaker cables, electrostatics, as they present a capacitive, not resistive, load, so can require different specifications.

 

[Symphoniac]

"...Our knowledge of engineering, confirmed by measurements and science of psychoacoustics says there is no audible difference...."

Actually, no, that's not at all correct. Only statistics from careful blind listening tests can show that. There is NO WAY that electronic measurements alone can PROVE there are no audible differences. It's a very unscientific statement to say that you know the results of any regime of careful blind listening test before such tests are actually conducted. Smacks of hubris.

I suspect that careful listening tests such as I've described would show that in fact no one can hear differences. But that's just a GUESS and this is supposed to be Audio SCIENCE Review and there's no place for guessing in real science. So where are the blind listening tests? They should accompany the electronic tests to prove the thesis that the electronic tests show no audible differences exist. Without results from blind listening tests the whole premise collapses.

I agree with your statement in principle, but in practice, (respectfully) this is an unreasonable thing to say. Not all things have an equal prior probability of being true, and therefore do not merit the same degree of scientific investigation. For example, the probability that a person can engage in pre-cognition (aka "see/feel the future") is very low. In recorded human history, there has been no verified proof of anyone reliably seeing the future (aside from anecdotes which abound, but this is similar to the common anecdotes of audiophiles hearing the difference for all sorts of things), and therefore the prior probability of this supernatural phenomenon is very low. Brain and physiological measurements would show that there is no difference between normal people and people who purport to see the future. We can reasonably conclude that pre-cognition is false, without doing randomized controlled experiments in which we test the purported abilities of pre-cognition person. Why should Amir expend further energy/resources into blind testing even after showing no audible difference in measurements across 2 or 3 different opamp rolling studies? I would rather Amir move onto more speaker reviews. Not trying to pick a fight, but I feel that people tend to stick so rigidly to these scientific principles without considering the potential cost.

 

[Curupira]

So you'll telling me that Sparkos' discrete solutions measure about the same as ICs? I'll definitely stop buying them then, I want musicality in my stuff, not pretty line in a graph

Spoiler

/s

 

[Cbdb2]

I can not disregard thousands of people who have swapped their 5532 and heard an improvement.

Do you disregard the thousands of people who have tried copper bracelets and felt an improvement or the thousands that think the earth is flat.

 

[Jimster480]

Nice test, it is great to see that actually the Sparkos OpAmp actually improves the performance in general, even if it is negligible and shouldn't be audible.

 

[amirm]

Nice test, it is great to see that actually the Sparkos OpAmp actually improves the performance in general, even if it is negligible and shouldn't be audible.

It didn't improve anything.

 

[SMen]

Fascinating test @amirm . I tried the Muses02 's that came with the kickstarter and put the NE5532's back in. Subjectively I did not actually prefer the NE5532's
I found it frustrating that Fosi were promoting this rolling.

I could never understand why they had two op amps in this part of the circuit. I don't suppose you can enlighten on this?

3e use one op amp per channel, as do many others. I'd love to understand the design rational behind two (apart from selling additional op amps).

 

[Ported]

Great stuff Amirm .. have bought - used plenty of studio gear utilising the 4558 boasting how much better than the 741 this was. Usually for low gain buffer or balanced line type usage. So for me it would have been quite interesting to add a 741 based equivalent to the mix to see if any progress was actually needed in an op amp for these particular applications.

 

[antcollinet]

I may be guessing here, but in my case, i suspect the 5532 puts a "heavier load" on the input connections compared to 4558.

No, that is not how they work. In order for an op amp to work as an op amp, the input bias current is very close to zero (typically around 1uA for a BJT input - down to 1/1000th of that for a mosfet input op amp) compared with the current though the input and feedback resistors. It will have no impact on the gain of the circuit.

And in any case, both those opamps have very similar input bias currents.