Does Op-amp Rolling Work?

[Sokel]

After informing with Audiophonics they basically said: op-amps are op-amps, and virtually all are interchangeable. Just for fun I tried rolling the stock op-amps in my HPA S-400ET with a working pair of BurrBrown OPA2134PA. After correctly installing them, the amp did NOT like these at all and started having sonical issues. I swiftly replaced them back with the stock ones, and all was well again. There might be an electronical reason (one of the numbers on the product sheet I don't understand that explains this) but my adventures in op-amp rolling ended there. The BB's are back in my Aiyima A04, where they do an excellent job of making no difference at all compared to the stock op-amps that it came with, which I deemed, trough reading many and wrong forums, not 'musical' enough. They will remain the only op-amps I'll roll.

Now that you said 2134...


OPA2134P


LME49720



Both for easy view.

Nothing to see really, but LME did got a small penalty in noise while BB got a little elevated H2.
Both, totally inaudible.

(Identical conditions, needless to say, that's an x-over there so it made sense to measure low to see if we have any of the potential know issues with filtering low)

 

[Geert]

Nice work again, but it would have been nice to have a null test included because lots of audiophiles only believe in (or can related to) testing with real music.

There's an opamp swapping thread on gearspace.com where opamps in an API mixing console got swapped and lots of people share their preference. Until a party pooper steps in with a DeltaWave null test to show there's no difference, and asks people for a blind test. 147 posts follow after that question, but it never got answered of course ...

 

[Bob101]

I think until we Test it we never know.

Consider this that test...

 

[JSmith]

The opamp song... to the tune of Rawhide;

Rollin', rollin', rollin'
Rollin', rollin', rollin'
Rollin', rollin', rollin'
Rollin', rollin', rollin'
Op-amps

Keep rollin', rollin', rollin'
Though the circuits are swollen
Keep those opamps rollin'
Op-amps

Through noise, distortion together
Hell-bent for better
Wishing my sound was clean and wide
All the things I’m changin’, good gain, smooth and flowin'
Are waitin' at the end of my ride

Move 'em on, swap 'em out, swap 'em out, move 'em on
Move 'em on, swap 'em out, opamps
Cut 'em out, roll 'em in, roll 'em in, cut 'em out
Cut 'em out, roll 'em in, opamps

Keep movin’, movin’, movin’
Though they’re disapprovin'
Keep those opamps movin’
Op-amps

Don’t try to understand ‘em
Just swap and tweak and brand ‘em
Soon we’ll be soundin’ high and wide
My heart’s recalculatin', my true sound is waitin'
Be waitin' at the end of my ride

Move 'em on, swap 'em out, swap 'em out, move 'em on
Move 'em on, swap 'em out, opamps
Cut 'em out, roll 'em in, roll 'em in, cut 'em out
Cut 'em out, roll 'em in, opamps

Rollin', rollin', rollin'
Rollin', rollin', rollin' (yeah)
Rollin', rollin', rollin' (yeah)
Rollin', rollin', rollin' (yeah)
Op-amps (yeah, yeah, yeah)
Op-amps!


©
JSmith

 

[MaxwellsEq]

The performance lays in the execution of the whole circuit not a single component, a badly chosen one can ofcourse break it , but that’s typically not because it’s “bad” but just not a fit for the circuit at hand .

^^ This is an excellent summary.

 

[morillon]

When I post my last video on review of Douk A5 amplifier, I mentioned that rolling (changing) op-amp ICs in there is fruitless. I got have a dozen comments under that video in youtube asking why so I thought I experiment again with the A5. Note that I have done the same testing with both DACs and Power Amplifiers and found the change to not make a difference. But let's see if the results are different this time.

View attachment 436787
The Douk A5 makes this job both easy and hard. It is easy because you can just lift the plexiglass and replace the op-amps. The difficulty was replacing the standard TI NE5532P opamp with the discrete Sonic Imagery Labs as it was too larger to fit in there. I pushed the adjacent caps more than I was comfortable with to get it to fit. Fortunately it worked.

There is a massive cost difference with the stock NE5532P costing US 57 cents in single quantity compared to minimum of $49 I found for the Sonic Imagery 994Enh-Ticha dual opamp. You would need two of them for stereo operation which would represent a premium that matches that of the amplifier itself! Here is a close up shot the 994Enh-Ticha:

As you see in the above picture, i decided to replace the right channel (Ch 2 below) and left left channel (Ch 1) the same. That way we can compare the two channels simultaneously under the same environmental situation. Amplifiers are temperature sensitive and shutting down to replace the opamp and powering back up would have created another variable. Alas, there is also channel to channel variations so the testing is not 100% exact but very close as you see below.

Opamp Rolling Measurements
Here is our usual dashboard:

View attachment 436792
As we see the performance is the same with SINAD which sums noise and distortion. This is of course at one power level so let's sweep the input voltage and measure at all power levels up to clipping:
View attachment 436793
There is the tiniest gap between the two but that may just be variations between channels. Even if it weren't so, it is a miniscule difference.

Maybe the differences becomes more visible if we use other frequencies than 1 kHz represented above:
View attachment 436795

I have zoomed into this graph to make differences larger. Dashed line is the Sonic Imagery discrete op-amp. We see that both at 15 kHz and at less than 500 Hz, the discrete amplifier is actually worse! But again, that could be variations between channels.

I wanted to investigate that a bit more so ran a couple of FFTs at both 100 Hz and 1 kHz:
View attachment 436797




View attachment 436798
The profile of distortion changes but not the high-order message that any difference is relegated to high order harmonics that are at or below threshold of hearing.

Discussion And Conclusions
It is natural to assume that the much more expensive, larger and fancier hand-made opamp IC would do better. All is not as it seems. An integrated circuit (IC) benefits from high precision components and even components that cannot be instantiated using discrete parts. Path lengths are also shorter allowing for better optimization of the design. Mass production using automated systems follows up by sharply reducing its cost.

On the other hand ICs can be subject to thermal coupling where rise in temperature in one part of the IC can negatively impact the performance of the rest of the IC. This doesn't apply here because the opamp is used at the front-end of the amplifier that is not attempting to produce power (only acts as a buffer and/or gain stage). Importantly, there is feedback that is used to correct the non-linearities in the op-amp. This correction highly linearizes both discrete and integrated op-amps as to almost erase any signature of the original part. This is why we don't see much difference in measurements.

People report improvements in sound and with it justify the upgrade. As members of this forum well know, such listening tests are improper. Testing must be controlled to exclude all extraneous (non audible) factors. When done, the measurements powerfully predict no audible difference. Indeed, I only know of one research paper that dug into sonic differences in op-amps and that only happened when the opamp was vastly overdriven.

Finally, I am not saying that all opamps are the same. There are countless ones for a reason. But unless you have instrumentation such as I am using, you have no prayer of knowing if a change improves anything. Or worse yet, made things worse. Here are the results form the DAC test:

There we do see a bit of differentiation but not enough to bother with any of this.

Net, net, leave the engineering to well, engineers! But a performant audio product and use it as is. Don't risk damaging and spend money on something that has essentially no chance of doing you any good.

Video version available as well:

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

It is necessary to check its role and if it is really completely compatible, without oscillation etc...
but I find it a shame, for example, that this test was not done on the small fosi preamp, recently review, which allows it...and which is very basic and simple...

the impact ... or not...,objective or subjective, could be much more relevant, perceptible or measurable...or not ;-)
more funny
....

 

[morillon]

When there is a need to read the datasheet, then op-amps are different

When people are just changing op-amps without looking at datasheet and the circuit around it, then op-amps don't make a different.

can...but clumsily, see in a negative way, see it go into oscillation etc... ;-)

 

[Graham849]

ArchImago reminds us in a lengthy write:​

“ MUSINGS: Trust, empirical testing, and evidence in the Audiophile hobby. And the Double Blind Test (DBT) strawman argument“​

MUSINGS: Trust, empirical testing, and evidence in the Audiophile hobby. And the Double Blind Test (DBT) strawman argument.

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[Haskil]

Not sure what the purpose of this thread is, other than to stir the pot even more on opamp rolling. Maybe start an argument to get engagement?

The power stage is the limiting factor here, not the opamps.

On another note, the 994enh SI opamps run hot and can pull quite a bit of current. I've got a few cooked ones here.

Um... it wasn't Amir who designed this device, but Douk, who gave its owner the option to swap the AOP for another one in order to get a sound like this or that... And Amir, logically, tried to see what the performance would be like.
And we see: nothing.

 

[DavidEdwinAston]

C

I’ve rolled a few op-amps over the past half dozen years and could never really distinguish any difference in the before/after sound. The certainly shows why.

Rolling your amps with some new chips is cheap, clean fun (but that’s all it really is.)

QED

An I ask, how is it any fun at all?

 

[Lambda]

better op-amps, what is better about them

read Post: https://www.audiosciencereview.com/...op-amp-rolling-work.61518/page-2#post-2255021

and do any of those parameters apply to the application under discussion here?

sure.
input and output current and voltage noise for example.

but which parameters are relevant depends on the application— and if or how much this would translate to better output performance.

As i said ther absolutely can be a "better" DAC but this dose not mean you hear a difference if its integrated in a system.

So the DACs are tested in isolation

 

[Yevhen]

So you think someone who has built a state of the art power stage, left room on the table on the front-end buffer/gain stage?

I think Hypex does that. They deliver a state-of-the-art power stage, and guys like Marantz add the preamp stage with their "signature" sound. Of course, in many cases that signature sound is more about adding some signature nonlinearity, basically ruining the overall performance

 

[Bob from Florida]

Manufacturers and distributors of expensive op-amps benefit from this in general.
Manufacturers building audio gear that has specific provisions for 'op-amp rolling' benefit as people want the 'experience'.
Also the buyers/swappers benefit as they feel 'their ... device sounds MUCH better' while technically nothing has changed.
In some rare cases there might be a genuine improvement in technical performance or there might be worsening.
In some cases there might even occur oscillations which may or may not be audible.


Placebo does... but that is not in the list of reasons to select the right op-amp for the job.

The weird thing is that no matter how often measurements show no discernible differences the op-amp swappers will continue to swap and continue to 'report' their findings and encourage others to 'swap' a bunch of op-amps because they want to hear 'better sound quality'.
There is a large audiophile community that is built on placebo and no matter how well we try we can't change their minds... in fact it makes the gap between the worlds even bigger.

What reviews like this ARE good for is for people that like to see things measured and realize audio electronics is just electronics and is bound to physics.
Unfortunately this group of people is very small compared to the audiophile and audiophool group.
Fortunately the actual test data is made available here which is a good thing .... as well as the fact that it can be discussed when measurements are made.


There is no 'synergy' here but audiophiles love that word. The circuit they are in does not have an influence of the overall performance of the device it is in except when a not well suited op-amp is used in which case the performance could be worse. Fortunately for swappers this could still mean an improvement.
It is nice for 'op-amp swappers' that the option is easily accessible.
It is nice for op-amp-manufacturers that they can sell a few more opamps (gear manufacturers order by the thousands).
It works wonders for owners who can finally hear things they want even if there is no actual improvement happening.

Exactly - and if I may add: it is clever marketing to put them in sockets and point that out.

 

[007Shorty]

There's one thing I find suspicious, though. Why does SINAD increase slightly on both channels when Amir replaces the 5532 on one channel with the discrete op-amp?

Are there additional buffer capacitors on the discrete op-amp's circuit boards?

 

[Schlippwhip68]

Well that’s interesting. Other than slight differences in frequency such as bass, mids and highs the op amp thing can end up more OCD than it needs to be in my experience. It also can make the situation worse when after experimentation you are left indecisive of which to leave in.
An interesting thing I found was different brands of the same op amp would sound slightly different. I tested a Philips NE5532 against the TI and JRC versions. In my own, non measured, subjective probably, simple ear testing I found the Philips bettered the others.

 

[nonloso]

I'm late to the party, but I'd like to have a different take (apologies to all engineers and those who run businesses for the oversimplification).
The discussion started on changing OPAs on the input buffer. That is certainly a fun hobby, but from the industrial point of view I think that:
- designing an input buffer based on integrated OPAs is cheap in terms of both parts and labor cost
- designing an input buffer based on discrete components is cheap in terms of components, but expensive in terms of labor
- designing an input buffer based on "discrete OPAs" is cheap in terms of labor, but expensive in terms of components
There are some important choices to be done in terms of expected performance, price target and units sold, in order to match the economics and perhaps the marketing image of one brand. I'm not sure if I have seen any brand selling their equipment with "discrete OPAs" installed by design.

 

[DMB90]

There might be some other limiting factor in this particular amplifier as NE5532 can do better than THD+N 0.003.

 

[NTTY]

There's one thing I find suspicious, though. Why does SINAD increase slightly on both channels when @amirm replaces the 5532 on one channel with the discrete op-amp?

Are there additional capacitors on the discrete op-amp's circuit boards?

View attachment 436918
View attachment 436919

With 32k FFT and 3 averages, you can have slight differences between two measurements, other potential small variations in setup aside.
What’s to look at here is the second measurement you’ve put of ch1 and ch2. They are the same.

 

[NTK]

There's one thing I find suspicious, though. Why does SINAD increase slightly on both channels when @amirm replaces the 5532 on one channel with the discrete op-amp?

Are there additional capacitors on the discrete op-amp's circuit boards?

View attachment 436918
View attachment 436919

Here are the two measurements side-by-side. The original amp review measurements had a slightly higher H3 (~ -92 dB @ 3 kHz) that accounted for the difference. The measurements after the 1 channel op-amp swap resulted in a ~ 2 dB reduction in the H3 spikes, but added some AC main spikes that didn't affect the aggregated SINAD number.

This underscore the highly sensitive nature of measurements at these low SINAD levels. Any seemingly minor changes may result in some "measurable" differences. They may be the run-to-run variations, differences in the time and number of reading averaging, moving some wires around, component temperature differences, etc.

 

[NTK]

There might be some other limiting factor in this particular amplifier as NE5532 can do better than THD+N 0.003.

Took you a year before your first post!

The answer to your question is perhaps the TPA amplifier that does the heavy lifting of the speaker level amplification? ... which points to the point (or lack of so) for this kind of op-amp rolling exercises.