Does Op-amp Rolling Work?

[KL....]

Then there are quite a few 'brick' manufacturers which ones to pick for that test ?

Thank you, yes, this encouraged the suggestion but only for discussion, first, and if reasonable then/perhaps measurement :=)

 

[Postlan]

when I replaced the DAC chip from TLE2074 to OPA1644, the noise level improved by about 4 to 6dB. Not all op-amps have the same performance.

 

[Mnyb]

However op-amp trolling seems fine

 

[Heinrich]

However op-amp trolling seems fine

Last try, promissed! See my post #463, pointing to a real scientist on youtube. Why do you still try to educate people wiith an engineering approach? Those to be addressed simply do not accept it. Not because they are ignorant in the first place, it is another philosophy. They are right in some aspects. See for instance google "Zeteticism - The Flat Earth Wiki" (exact word).

It's irrelevant though, as part the goal of high fidelity audio literally is minimal distortions and noise.

The engineer aims for a target. To lower distortion follows a prejudice on what the listeners need. The science would ask, is it true? As a word of caution, it was shown that it is not as natural as it seems. What is it worth to minimize HD for instance way beyond the threshold of audibility?

My answer is, the engineers, in lack of clear and final scientific approval, aim for a plausibility argument. If linearity is as good as it shows, the likelihood of any other disturbance (to a human) than distortion (to a machine) is as low as that, give or take. It is not about evidence, but plausibility.

Me, as a scientific minded person would ask, show me your concept of linearity, the power series in a pertubation theory, what have you? I don't only because I trust common sense, in the sense that we all rely on the validity of experience of earlier generations with problems like that.

Do you see how the sceptic would dismiss every contribution from the engineering side, just because he/she cannot "feel" it? Cannot trust logic over personally involved experience, cannot trust other peoples' words finally.

So, you may go on with once and final experiments, discuss parameters, but it is going to be void. Addressing a philosophical attitude needs the humanities, not engineering.

cu

ps: before starting to run in perfect circles, I better invent a time machine ..

 

[JSmith]

To lower distortion follows a prejudice on what the listeners need.

What?


JSmith

 

[Heinrich]

What?

What else, JSmith? Follow the science.

 

[antcollinet]

What is it worth to minimize HD for instance way beyond the threshold of audibility?

None.

But it is only relatively recently that "way beyond" has been routinely achieved at low cost.

Now we have it. And changing op amps never changes it from inaudble to audible.(as long as sensible choices of op amps are made - of couse it is possible to select one that just doesn't work for the application)

Even more importantly - changing an op amp never changes THD+N from inaudble to even-more-inaudible.

 

[Blumlein 88]

Zeteticism is just another example of Brandolini's law.

 

[Gorgonzola]

I've been distained a good many times for reporting my purely subjective and impressionistic findings, so I'm used to the abuse. I've rolled op amps a few times and have found subtle differences.

Most striking was my recent experience with my VTV Purifi 1ET400A stereo amp. Originally I ordered this from VTV with the Hypex Eval I/O buffer. Immediately and spontaneously I was disappointed with at least one aspect of the sound versus my previous Hypex NC252MP amp; the top end, especially and higher volumes, was "screamy" and unnatural. Almost right away I ordered VTV's own I/O buffers with Sparkos SS3602 (discrete) dual op amps. The VTV buffers that accommodate 8 pin DIPs and larger form factor "pro" op amps.

With the VTV buffer with the SS3602's the sound was improved in that top end respect: "screaminess" gone. However I proceeded to try several other op amps I had lying around from previous experimentation, including OP2134, the venerable OPA247, the Burson V6 Vivid discrete, plus I ordered the OPA1612.

My personal, subjective conclusion after much swapping back & forth was that I preferred the Sparkos SS3602's for having the nicest transparency and natural top end. Runner up was probably the OPA1612. It's worth mentioning that the VTV buffer was designed by the same designer as the Sparkos op amps, (which I didn't know at the time), so the fact might have optimized the buffer and op amp combination.

But I note & emphasize that difference among these op amps were extremely subtle excepting for the Hypex buffer that was distinctly awful in context of my VTV Purifi amp. (I knew but now don't recall the surface mount op amp used in the Hypex.)

 

[Multicore]

Then again ... how far does one have to go to convince some folks that say ... weeelllll... ?

Not very far. As I keep saying, the onus is on the op-amp swap boosters to show that their claims of audible differences are repeatable in controlled conditions.

I know it's not trivially easy to do this but it's not all that hard either. And the rewards would be enormous to those who demonstrate that op-amps do not in fact work as we understand them to. The costs and time involved would be, what, about the same as producing a dozen audio pundit YouTubes?

We can volunteer to review the test design and verification in good faith to ensure that there won't be objections to the results after the fact. If at the end we can't agree on interpreting the result then it will have been a waste of time.

 

[KL....]

I've been distained a good many times for reporting my purely subjective and impressionistic findings, so I'm used to the abuse. I've rolled op amps a few times and have found subtle differences.

Most striking was my recent experience with my VTV Purifi 1ET400A stereo amp. Originally I ordered this from VTV with the Hypex Eval I/O buffer. Immediately and spontaneously I was disappointed with at least one aspect of the sound versus my previous Hypex NC252MP amp; the top end, especially and higher volumes, was "screamy" and unnatural. Almost right away I ordered VTV's own I/O buffers with Sparkos SS3602 (discrete) dual op amps. The VTV buffers that accommodate 8 pin DIPs and larger form factor "pro" op amps.

With the VTV buffer with the SS3602's the sound was improved in that top end respect: "screaminess" gone. However I proceeded to try several other op amps I had lying around from previous experimentation, including OP2134, the venerable OPA247, the Burson V6 Vivid discrete, plus I ordered the OPA1612.

My personal, subjective conclusion after much swapping back & forth was that I preferred the Sparkos SS3602's for having the nicest transparency and natural top end. Runner up was probably the OPA1612. It's worth mentioning that the VTV buffer was designed by the same designer as the Sparkos op amps, (which I didn't know at the time), so the fact might have optimized the buffer and op amp combination.

But I note & emphasize that difference among these op amps were extremely subtle excepting for the Hypex buffer that was distinctly awful in context of my VTV Purifi amp. (I knew but now don't recall the surface mount op amp used in the Hypex.)

Ah, you are aware that this is subjective but a (relevant) impression and your whole system and room needs to be taken in context/consideration (alot of variables there, isn't there?) because it is subjective and an impression. Perhaps, the question/s that could be asked of Hypex/Sparkos is what are the technical reasons and why? Fortunately, in this instance, your situation was sufficiently resolved but were technical reasons and why they were resolved, provided to you by them? If they haven't provided this information to you then it can only be received as, in this instance, it sufficiently resolved your situation and may not be beneficial/helpful to others.... that is a reasonable conclusion, isn't it? Know that measurements are helpful/needed, especially when well/accurately applied and interpreted, aren't they?

Edit: The main aspect for you, especially in this instance, is that you enjoying your system/music (even) more. Keep in mind that this experience may not be necessary for others but it could be helpful which means sharing your experience in those instances is helpful but (even very) limited, why? because at some point you need to be objective to achieve a reasonable (repeatable) conclusion.... that is reasonable, isn't it? Note that an objective conclusion also applys to your subjective but (relevant) impressions.... enjoy :=)

 

[Multicore]

I've been distained a good many times for reporting my purely subjective and impressionistic findings

I like the word impressionistic in this context.

 

[peng]

I've been distained a good many times for reporting my purely subjective and impressionistic findings, so I'm used to the abuse. I've rolled op amps a few times and have found subtle differences.

I wonder why anyone would do such "abuse" when You emphasized "subjective, impressionistic..", and then added "subtle". All that would, to me anyway, indicate you might even believe chance might be good that in DBTs, you might find that subtle difference become more subtle or disappear, or unsure if it is there.

 

[NTTY]

Last try, promissed! See my post #463, pointing to a real scientist on youtube. Why do you still try to educate people wiith an engineering approach? Those to be addressed simply do not accept it. Not because they are ignorant in the first place, it is another philosophy. They are right in some aspects. See for instance google "Zeteticism - The Flat Earth Wiki" (exact word).

I had a good laugh, thanks.

I’ll be eagerly waiting for a future Zetetic DAC, and I’ll ask «Does it taste good?». I’ll then cook it in a zillion different ways, if necessary, to reply (positively) to the question.

I wonder if it’d be best to stir or fry the OPamps. I’m sure measurements will not tell anything about that. Eat this @amirm

 

[solderdude]

As I keep saying, the onus is on the op-amp swap boosters to show that their claims of audible differences are repeatable in controlled conditions.

The problem here is that they have already 'proven' that the differences exist and have confirmation from the manufacturer and countless people.
Then we ask them to doubt that what they 'know to be true' and have to prove that they are right to a bunch of tech guys that only measure gear.

The procedure indeed is not that difficult, doing it properly is though and involves other people to assist which cannot give any 'hints'.
Doing this 'long term' (as that always seems to be the counter argument) takes months to complete.
Besides ... what IF these tech guys were right and it turns out statistically they cannot clearly identify that what they always could.
Are these people 'open' enough to accept that testing methods is what is paramount to perceive differences.

Never going to happen (well maybe a handful) so the 'opposing views' will continue and nothing would change.

 

[KL....]

Never going to happen (well maybe a handful) so the 'opposing views' will continue and nothing would change.

The testing and measurements are important/even critical, aren't they? but the delivery/expression of them (it could be suggested?.... :=)) is equally as important/even critical and subjective assumption is not objective assumption, is it? (is that even an expression? Perhaps, 'to Assume makes an Ass out of U and Me' provides more clarity).

@amirm, thank you for taking the time to test and measure, very much appreciated and for me, as are all the posts, thank you :=)

 

[NTK]

I've been distained a good many times for reporting my purely subjective and impressionistic findings, so I'm used to the abuse. I've rolled op amps a few times and have found subtle differences.

Most striking was my recent experience with my VTV Purifi 1ET400A stereo amp. Originally I ordered this from VTV with the Hypex Eval I/O buffer. Immediately and spontaneously I was disappointed with at least one aspect of the sound versus my previous Hypex NC252MP amp; the top end, especially and higher volumes, was "screamy" and unnatural. Almost right away I ordered VTV's own I/O buffers with Sparkos SS3602 (discrete) dual op amps. The VTV buffers that accommodate 8 pin DIPs and larger form factor "pro" op amps.

With the VTV buffer with the SS3602's the sound was improved in that top end respect: "screaminess" gone. However I proceeded to try several other op amps I had lying around from previous experimentation, including OP2134, the venerable OPA247, the Burson V6 Vivid discrete, plus I ordered the OPA1612.

My personal, subjective conclusion after much swapping back & forth was that I preferred the Sparkos SS3602's for having the nicest transparency and natural top end. Runner up was probably the OPA1612. It's worth mentioning that the VTV buffer was designed by the same designer as the Sparkos op amps, (which I didn't know at the time), so the fact might have optimized the buffer and op amp combination.

But I note & emphasize that difference among these op amps were extremely subtle excepting for the Hypex buffer that was distinctly awful in context of my VTV Purifi amp. (I knew but now don't recall the surface mount op amp used in the Hypex.)

The Hypex NC500 Evaluation board/buffer was designed for engineering evaluation only, and lacked the necessary components (capacitors in the feedback path and at the inputs to the op-amps) to limit the signal bandwidth and is therefore much more susceptible to RF interference. Using it in production amplifiers (which was, AFAICT, not Hypex intention) is one of the reasons VTV got its bad rap early on on this forum. The omission can certainly lead to poor performance in real life applications.

Below is a comparison of the Hypex evaluation buffer and the later Purifi eval board for its 1ET400A (which Purifi sells to end customers).

 

[antcollinet]

I've been distained a good many times for reporting my purely subjective and impressionistic findings

Bit of an exercise in futility doing it all again then

My personal, subjective conclusion....

Still - why let that stop you.

Point is "purely subjective" findings can only be of interest to the subjective listener. They cannot inform anyone else about what they might perceive in the sound from a piece of gear. (by the very definition of the word subjective). No-one knows if your "impressions" come from the sound, or from your unconscious brain.

It therefore makes it pretty pointless reporting on them. Here, at least.

 

[Sokel]

Does anyone want me to change and mix not one, but seven OPAs (three and a half double ones for accuracy) in the following fashion and see what happens:

To save you the trouble of interpreting charts (specially those of you who think that "they don't tell the whole story" so you don't really like or understand them) :

Nothings happens, zero, with compatible ones. With the wrong ones yes, sure, some things happen, things that no audio system deserves.
Mild ones like some elevated noise or not so mild as outputting some serious DC.

If you care for your gear and can't resist the urge of this silly practice at least measure your gear for DC after changing the OPAs that were made for them.
You will give your amps and speakers a great service, I promise.

 

[ckernel8]

Why is to roll the verb for this component swapping? And how did that come about?

It's because tubes physically roll.