Is it scientific to grade the modern DAC chips like AK4497?

[Jason C]

I know that in the 1980s ~ 1990s, some DAC chips are graded, for example the selected TDA1541 chips are marked with crown mark, but is it scientific to grade the modern DAC chips like AK4497?

The Chinese brand Luxury & Precision have released their new DAP model E7 in February this year, there are two versions as standard edition and exclusive edition, it is alleged that the exclusive edition is using the selected AK4497 chips, which have better performance.

Of course, there are some doubts about the chip selection, the L&P customer service replied as following: (translated by Google)

“Maybe we didn't express it clearly. First of all, the consistency of AKM products is actually pretty good, but it may not be as high as you think. Our selection is aimed at picking out the ones with better performance. The typical THD+N performance of AK4497 is -116db, and the worst is -108db. It doesn't mean that the consistency of delta sigma must be very high. The THD+N of our carefully selected AK4497 card is controlled at around -120db.”

In my opinion, modern IC manufacturing is much more advanced and precise, in addition, AKM should have strict quality control procedure, so the 8db/116db about 7% performance deviation of the AK4497 chips is quite unbelievable to me. Unfortunately, I’m not specialized in the IC and circuit, would you guys tell me if it is truth or just a false advertisement.

Thank you!

 

[Father O'Blivion]

I'm certainly not an expert, but I do know in CPU/GPU manufacturing there is variation in output quality across even the same wafer, which results in some processors which fully pass testing and others that don't, which are then sold under a different SKU (i9, vs i5, vs i3, etc. see "binning").

Could there be something similar here? I don't know. I'm sure AKM would have a minimum threshold, but there certainly could be variation above it. Is it the sort of variation which could result in a different THD+N? No idea. Interesting question though. Hopefully someone who actually knows what they're talking about with DAC chips (unlike me) will chime in.

To be certain, if there is variation which could result in a few db difference from the same SKU chip, someone somewhere will come up with a scheme to cash in on it! Even if there is no real world audible difference.

 

[GXAlan]

If you look at the E1DA Cosmos ADC, there are different grades of performance but if you don’t care about the numbers, it’s excellent to even better.

Looking at the MUSES op amps, it seems like the minimum guarantee spec is mediocre but the actual measurements are very good. I could imagine some variability as well.

So the short answer is that for audible differences, it’s not really worth paying extra for premium grade ICs but for bragging rights, it’s a different story.

 

[bmc0]

Yes, performance of modern ICs varies to some degree unit-to-unit and batch-to-batch. Datasheets for just about any electronic part will provide typical specs along with minimum and maximum limits (where applicable). Some datasheets even provide statistical data for certain specs.

The quoted -116dB Typ. THD+N and -108dB Max. THD+N are straight from the AK4497 datasheet. See page 11 here if you want to check for yourself. That said, I doubt anyone could actually hear the difference between the best and worst performing units.