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Does the review of the Gustard X26 pro have incorrect info regarding Op Amps ?

Cut-Throat

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The following was the quote in the Sound News about the Gustard X26 pro.

"For the current to voltage conversion (I/V conversion stage), Gustard used only discrete components, not a single op-amp is found in its signal path. Its analog Low-Pass Filter (LPF) also uses only fully discrete components biased into Class-A. Again, no cheap op-amps are found in its signal path. This is a crucial part of any DAC, this is the reason it uses two toroidal transformers and this is why it dissipates so much heat."

So, I emailed the reviewer of the Gustard X26 pro and specifically asked him about the statement he had made in the review, and told him that it had been challenged on ASR by a few people. I just wanted to know the facts and felt that he would be interested in defending his review or at least getting the facts straight. Here was his response to me:

You can find all the X26 Pro info on Gustard's website, check it all here: http://www.gustard.cn/?post_type=products&page_id=11515
and here in English: https://shenzhenaudio.com/products/...5-0-xoms-xu216-high-performance-audio-decoder
I used that info as reliable and trustworthy information, if it is not, shoot Gustard an email and blame them for that. I for one, see discrete components at its LPF stage and separately at its filtering stage. You can see them too in my pictures and in the video.
Lets presume for a second that there are indeed op-amps somewhere in there, would it change my sound impressions, even by a tiny bit? Absolutely not.
I wish I would have time to play devil's advocate, but I don't have time for that.
Cheers!
Kind regards,
Sandu Vitalie
Owner & Editor


So, basically this reviewer “does not have time” to investigate the facts. So, I thought I would post my Questions to people that were more knowledgeable than me on the comments section of his review. Sandu Promptly deleted my Posts. As he did not want this discussion on his review.

So I am asking here about the Op Amps in the Gustard X26 pro. Is there any truth to the statement in the Gustard X26 pro? Or is this review have bad information?
 

voodooless

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Journalists not fact checking.. who would have thought.

And yes, it would have changed the sound impression he had since it’s totally subjective and therefore subject to all kinds of influences, the least of which the actual measurable properties of the thing.
 
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MakeMineVinyl

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sq225917

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They use bang up to date ones, cost is no arbiter of quality. Opa627 cost as much as 8 opa1612, opa1612 beats it in almost every measure.
 

levimax

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What's wrong with op amps? Just because they are cheap and easy does not mean that they are not very good performers..... good luck trying to "beat" the performance of an op amp with discrete components for line level signals.
 

half_dog

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Are they using OPA627? I might be wrong but OPA627 is a single channel and those ICs from the picture seems dual channel, no?
 

Billy Budapest

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For a product to claim it eschews opamps in favor of discrete implementation, it’s a bit ingenious when there are at least 33 IC’s in the output stage behind the D/A converter.

B85B76A4-959A-4F97-965B-6D370F125740.jpeg
 
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OP
Cut-Throat

Cut-Throat

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For a product to claim it eschews opamps in favor of discrete implementation, it’s a bit ingenious when there are at least 33 IC’s in the output stage behind the D/A converter.

Can you tell me where you saw this product 'claiming it eschews opamps in favor of discrete implementation'? -- I know the reviewer claimed it, but I have not seen when the Manufacturer did.
 

voodooless

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Current to voltage???
Yes.. what is your question?

From the text on the website it looks like the low pass filter is discreet, the rest is done using op amps.
 

sq225917

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Discrete just means built with transistors, not opamps. But there are opamps hidden between 5he bigger caps
 

Billy Budapest

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Can you tell me where you saw this product 'claiming it eschews opamps in favor of discrete implementation'? -- I know the reviewer claimed it, but I have not seen when the Manufacturer did.
It’s mentioned multiple times on the product page here:

https://shenzhenaudio.com/products/...5-0-xoms-xu216-high-performance-audio-decoder

Although on the same page, there are pictures of opamps and other ICs and packaged components right next to the word “discrete”!
 

Billy Budapest

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Discrete just means built with transistors, not opamps. But there are opamps hidden between 5he bigger caps
It doesn’t mean just transistors. Discrete circuitry also means diodes, resistors, current regulators, etc., are implemented as individual components (hence, “discrete”) as opposed to being packaged together in miniaturized form on a silicon wafer in an IC.

The audio press’ preference for discrete circuitry is just propagation of an audiophile myth.
 
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voodooless

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Why would a DAC convert current to voltage?

The DAC doesn’t (at least not this one). These DAC’s are current output devices. To use the signal in the rest of the chain, you’ll need to convert the variable current to voltage. The crudest I/V is simply a resistor, but those will not give state-of-art performance. Specialized op amps are very good at this however.
 

sq225917

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It doesn’t mean just transistors. Discrete circuitry also means diodes, resistors, current regulators, etc., are implemented as individual components (hence, “discrete”) as opposed to being packaged together in miniaturized form in an IC.

The audio press’ preference for discrete circuitry is just propagation of an audiophile myth.

Yeh, I know
 

kopczas

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Not exactly hidden...

If you try to go thru Walt Jung`s book about opamp application (which has more then 600 pages of content) you`d learn that if you see opamp in audio device it not necessarily means signal goes thru. Or even so, it`s probably some buffers that would lower circuit impedance. Nothing really to cry about.
 
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