Opamp fakes vs real vs audiophile

[0bs3rv3r]

Just thinking today, while looking at Asian markets selling opamps and opamp based preamp boards, about the prevalence of fakes, or likely fakes, in the market. Then I recall the various tests that show opamp rolling might not make much difference.

So, does it matter that my OPA2134 might be a 5532, or something obscure? My experience is that these preamp boards almost invariably work, and work quite well. I have also never bought an opamp that didn't work, although, yes, there are reports of that happening. Lately you can buy nearly anything, even discrete opamps, video opamps (like AD828), etc etc being sold as audiophile opamps.

But, if the tests are right, there is not enough difference to really matter, and if you like what you hear, so does it matter if the 2134 is a 5532 or a TL072?

 

[antcollinet]

Then I recall the various tests that show opamp rolling might not make much difference.

Let me put a caveat on that. Op amp rolling will never make an audible improvement to a competent design. But it can certainly degrade performance significantly. And a fake one is quite likely to.

See:

Does Op-amp Rolling Work?

Purifi just released their deluxe EVAL8, EVAL9, & EVAL10 with FET-input discrete OPAMPs. Will they roll?

www.audiosciencereview.com

 

[0bs3rv3r]

Let me put a caveat on that. Op amp rolling will never make an audible improvement to a competent design. But it can certainly degrade performance significantly. And a fake one is quite likely to.

See:

Does Op-amp Rolling Work?

Purifi just released their deluxe EVAL8, EVAL9, & EVAL10 with FET-input discrete OPAMPs. Will they roll?

www.audiosciencereview.com

But one of the ways they fake expensive opamps is to use a cheaper (although otherwise good) opamp. So, I think many fakes would work well and never be discovered. Sure, there might be some fakes that are this bad, but I actualy haven't found one yet myself. So, is it really "quite likely" these days?

As an aside, I really have trouble believing discrete opamps are automatically better than chip opamps. I would bet people selling 5532 chips hidden inside an audiophile opamp, discrete or otherwise, would easily get a free pass.

 

[antcollinet]

As an aside, I really have trouble believing discrete opamps are automatically better than chip opamps.

They are not. In many cases they are measurably worse.

 

[Sokel]

But one of the ways they fake expensive opamps is to use a cheaper (although otherwise good) opamp. So, I think many fakes would work well and never be discovered. Sure, there might be some fakes that are this bad, but I actualy haven't found one yet myself. So, is it really "quite likely" these days?

As an aside, I really have trouble believing discrete opamps are automatically better than chip opamps. I would bet people selling 5532 chips hidden inside an audiophile opamp, discrete or otherwise, would easily get a free pass.

The only reason you see this one measured is because I have a little silly separate circuit which I use only to play with, there's no way I would stick a questionable origin opamp (or even a real, bad one, but that's just the paranoid me) in a real piece of hi-fi gear.

And that only AFTER I checked for DC being on all night before that, my poor interface has no reason to suffer from stuff like that.
I cannot begin to describe to you what such a waveform can do depending the conditions.

Just stay clear, you may not notice something audible (until a spectacular bang) but the way it works its way down the road is surely not nice for the rest of the chain.

Of a lot of 5 (or 4, I don't remember well) all but one was just as bad and the remaining one had one of its channels completely off
(the remaining one was strangely kind of ok)

Don't think of them as re branded, they are most likely both re-branded and rejected.

 

[DVDdoug]

I would hope the manufacturers are doing some tests on their production amplifiers to make sure they are in-spec. But they might just be doing quick-checks to make sure they function.

BTW - There's a possibility that the amplifier manufacturer is getting scammed if they are not buying from authorized distributers.

 

[0bs3rv3r]

The only reason you see this one measured is because I have a little silly separate circuit which I use only to play with, there's no way I would stick a questionable origin opamp (or even a real, bad one, but that's just the paranoid me) in a real piece of hi-fi gear.

And that only AFTER I checked for DC being on all night before that, my poor interface has no reason to suffer from stuff like that.
I cannot begin to describe to you what such a waveform can do depending the conditions.

Just stay clear, you may not notice something audible (until a spectacular bang) but the way it works its way down the road is surely not nice for the rest of the chain.

Yes, that is being a little paranoid. It comes down to understanding electronics down to the design level. Look, if you believe you can measure an opamp and predict whether it will sound better, then believe also, it can be measured and tested to work properly and be "safe".

 

[Sokel]

Yes, that is being a little paranoid. It comes down to understanding electronics down to the design level. Look, if you believe you can measure an opamp and predict whether it will sound better, then believe also, it can be measured and tested to work properly and be "safe".

The fake "OPA2134" you see measured is NOT safe. Not by a long shot.
Anyone with basic gear can test OPA's, at least for sanity reasons, it's not hard.

 

[0bs3rv3r]

I would hope the manufacturers are doing some tests on their production amplifiers to make sure they are in-spec. But they might just be doing quick-checks to make sure they function.

BTW - There's a possibility that the amplifier manufacturer is getting scammed if they are not buying from authorized distributers.

Interesting point. I suspect it happens at all levels. There will be some "manufacturers" who don't care. There will be some who buy built boards, stick anything in the sockets, and on-sell them on Aliexpress or where-ever. Then there will be those that, yes, indeed buy from, if not "authorized" then at least, trusted resellers.

But, as for testing, in my initial post, I had in mind a board or opamp, that at least functioned in the circuit.

 

[0bs3rv3r]

The fake "OPA2134" you see measured is NOT safe. Not by a long shot.
Anyone with basic gear can test OPA's, at least for sanity reasons, it's not hard.

I think you missed where I said "it can be measured and TESTED ", in which case, we agree.

 

[0bs3rv3r]

I would hope the manufacturers are doing some tests on their production amplifiers to make sure they are in-spec.

Again, on this subject, these boards, in many variations, seem to be everywhere, cheap, at the moment. Would the manufacturer have made sure they were soldering real chips to their boards? Maybe. Are they boards that failed to meet specs, and so are being sold cheap? Also maybe.

 

[mhardy6647]

Again, on this subject, these boards, in many variations, seem to be everywhere, cheap, at the moment. Would the manufacturer have made sure they were soldering real chips to their boards? Maybe. Are they boards that failed to meet specs, and so are being sold cheap? Also maybe.

View attachment 492504

It appears to be a microphone preamp(?)

 

[0bs3rv3r]

It appears to be a microphone preamp(?)

Yes, but it comes in many variations. Here's a general purpose audio preamp. Same point though - how likely is it that the opamps are fake? More likely the boards are made with good opamps and are surplus and being dumped. Also may be under spec when batch testing.

To my original point though, even if fake, if using a lesser chip inside (fake opamp scenario) - may still be quite functional and not audibly different.

 

[NTK]

No idea why they put an AD828 into this board. It is a video opamp per Analog Devices (i.e. for video signal applications). It is not particularly cheap at $4.12 each at 1,000 pieces.

https://www.analog.com/en/products/AD828.html

 

[Petrushka]

I’m so old I remember when failed industrial espionage gave us half a decade of short lived capacitors. Name brand computers that died after three years.

 

[RexrothPigeon]

I’m so old I remember when failed industrial espionage gave us half a decade of short lived capacitors. Name brand computers that died after three years.

be grateful that because of your advanced age your ears no longer require (or even perceive) hi-fi audio reproduction

( <-- also old )

 

[0bs3rv3r]

No idea why they put an AD828 into this board. It is a video opamp per Analog Devices (i.e. for video signal applications). It is not particularly cheap at $4.12 each at 1,000 pieces.

https://www.analog.com/en/products/AD828.html

Well, it has a high bandwidth, high slew rate, low power, single supply, etc., it also makes an excellent audio preamp. I have a couple in one preamp and they work very well indeed. Video is just high bandwidth audio in a sense. It is becoming popuar in audio uses, judging by what Asian markets are selling.

 

[NTK]

Well, it has a high bandwidth, high slew rate, low power, single supply, etc., it also makes an excellent audio preamp. I have a couple in one preamp and they work very well indeed. Video is just high bandwidth audio in a sense. It is becoming popuar in audio uses, judging by what Asian markets are selling.

You notice that there is no noise or distortion specs in the datasheet, because the intended applications don't care, do you?

 

[sonitus mirus]

Well, it has a high bandwidth, high slew rate, low power, single supply, etc., it also makes an excellent audio preamp. I have a couple in one preamp and they work very well indeed. Video is just high bandwidth audio in a sense. It is becoming popuar in audio uses, judging by what Asian markets are selling.

They left out audio noise and distortion because the chip was made for video use, and that matters because without those numbers you cannot tell how clean it is or how clear the audio will sound.

 

[0bs3rv3r]

You notice that there is no noise or distortion specs in the datasheet, because the intended applications don't care, do you?

They left out audio noise and distortion because the chip was made for video use, and that matters because without those numbers you cannot tell how clean it is or how clear the audio will sound.

Shooting the messenger a bit guys. The market is selling lots of these, and using typical descriptions like "fever" opamp. All I can say is that my one experience is that they work, and if I had to say, I'd say they may be better than a 5532 - but that's just an unscientific feeling. Also unscientific, but I have a feeling video requirements these days may include low noise/distortion to allow high dynamic range and 4k video to look it's best. Maybe they just loaf along doing audio. Go ahead and test them, but if the "audiophile market" is buying them, then at least the marketing is working.