Which DAC + Which ADC Are Focused On Making High Accuracy Measurements?

[LesOrr]

I am well versed in making reliable analog audio measurements. I am new to making similar digital measurements and/or combining the two.

I downloaded "Multitone Analyzer" from Pkane and ran a 1 kHz test sine wave out of my laptop several times into my Tekronix AA5001 Distortion Analyzer. As a result, I discovered that the Realtec HD Audio DAC, @ 100%, in my laptop puts out 1.1 V at 0.08 % THD+N for a timed interval and then stops. I simulaneously looked at the sine wave and the residual THD+N with my Tek 465B scope. I took and shared pictures with friends. I was told that my DAC isn't good enough.

I spent the week trying to get a grip on buying a DAC and an ADC which will be as useful for me as my Tekronix and Audio Precision test equipment. I am solely interested in making Reliable Reproducible Measurements - nothing else.

I found that there are units which vary in price from under $50 to $175000. All of the vendor sites and the related reviews I could find appear to tout a variety of features I don't want and subjective evaluations of 'better sounds' which are not relevant to my needs.

Since many of you who post on this site are way ahead if me with digiral testing, I would appreciate learning which test DACs and ADCs you use.

Thanks.

 

[staticV3]

If you want reliable, TOTL DAC and ADC performance, look no further than the APx555B. It's the gold standard in audio.

If you're on a budget, an RME ADI-2 Pro or ADI-2/4 SE will do nicely.

If you're on an even tighter budget, take a look at QuantAsylum and E1DA Cosmos.

 

[LesOrr]

APx555B. It's the gold standard in audio.

Thank you.

I received a demo of the APx555B when it was initially introduced. It was certainly spectacular. Not being a very rich hobbiest, I bought an AP SYS1. For my testing it has been good enough - with no digital testing.

I took another look at the APx555B this week. The analog modules and the software are still the gold standard from my viewpoint. I'm not as clear about the digital modules - It seems like time may not stand still in the 'digital domain'.

I read the RME ADI-2 Pro review from amirm dated Apr 19, 2018 very carefully. I also looked at the QuantAsylum and E1DA Cosmos products. I will look deeper.

I really appreciate your quick reply.

 

[LTig]

RME designed the ADI-2 PRO such that it can be used for measurements, and use them in their production chain for quality control.

I bought one and used it successfully with REW. It is good enough for most electronics except SOTA ADCs, DACs and preamps - those require an APx555. The Cosmos ADC measures a little better than the ADC in the RME but the latter has the advantage of its clock being synchronized with the DAC.

 

[AnalogSteph]

BTW, the average Realtek should be in the mid -80s dB THD+N at full blast, most of it H2. 0.08% thus sounds a bit much, but there may have been a ground loop involved and no band limiting (I wouldn't rule out seeing some shaped noise out-of-band), and I'm obviously assuming a sensible load in the high hundreds of ohms at least (50 ohms may be a different story depending on the chip's headphone driving capabilities).

Side note, the "Testing Area" is a literal area for testing things (i.e. basically a scratchpad), not for discussing test equipment. That I guess would normally go in Audio Interfaces (ADC & DAC).

 

[LesOrr]

... no band limiting ...

I test with all of the filters switched off. I hope to continue down that path.

BTW, which DAC + ADC do you personally use for testing?

Sorry about picking the wrong area - I'm new and the site organization has me a bit baffled. I just took a look at "Audio Interfaces" as you suggested - it seems to have little to do with testing, which is the only thing I am interested in. What link would get me to DACs + ADCs For Testing, not for listening?

 

[EERecordist]

Amir also reviewed https://www.audiosciencereview.com/forum/index.php?threads/audio-precision-apx516b-review.52335/. As you say, the AP software is expensive to maintain and very useful. RME is having a sale now, and there is an active secondary market for their equipment. On the AtoD side, the Cosmos has very good specs and a low price.

 

[johny_2000]

As separate units, E1DA Cosmos ADC + APU + Scaler as ADC, and E1DA #9039S + LPF as DAC. Budget friendly option and the highest specifications (higher than RME and AP).
Cons: multiple units with a lot of interconnects between them. May affect the quality of connections (cheap cables, connectors, oxidation) and the aesthetics of the workplace. And also some issues with ASIO drivers and clock sync if needed. SINAD 128-129dB for ADC "A" and 130-133dB for DAC+LPF.

The RME ADI-2/4 Pro SE and QuantAsylum QA403 are all-in-one units (though without the AES17 notch filter) that may be more convenient and easier to use right out of the box. A more expensive solution, but more reliable in terms of connections, drivers, technical support. SINAD is limited to ~120dB.

The APx555(B) as a gold standard for audio measurements is now obsolete (2018-2025, 7 y.o.) in terms of ADC and DAC+Analog Gen source hardware specifications. It is limited to 125-126 dB SINAD, which is already achieved by the most advanced devices, and probably already exceeded by some, but cannot be properly measured by the AP.

 

[LesOrr]

The APx555(B) as a gold standard for audio measurements is now obsolete (2018-2025, 7 y.o.) in terms of ADC and DAC+Analog Gen source hardware specifications.

Thank you for this observation. My simplistic research seemed to show the same thing - it was surprising. I assume that offering "APx500 Measurement Software" without hardware, which supports outside vendors' ADCs+DACs, is AP's attempt to stay useful in the so called Digital Domain. It gives AP customers the ability to continue to use their existing test scripts. I personally believe that the APx555B is still unsurpassed in the Analog Domain where I have spent my life till now.

BTW, which DAC + ADC do you personally use for testing?

...SINAD...

This term seems to be used frequently on the ASR site. Having spent many months 'restoring' a Tek DA4084 (in addirion to my AA5001) I am slightly familiar with SINAD. What is the specific relevance here?

 

[LesOrr]

As separate units, E1DA Cosmos ADC + APU + Scaler as ADC, and E1DA #9039S + LPF as DAC. Budget friendly option and the highest specifications (higher than RME and AP).

I was unable to figure out the 'rate' and 'bits' on the E1DA. Maybe you know?

 

[staticV3]

was unable to figure out the 'rate' and 'bits' on the E1DA.

The Cosmos ADC supports up to 768kHz sample rate and bit depth of 32bit integer.

Using the provided calibration files, frequency response is flat up to ~300kHz.

More details are on the product page: https://e1dashz.wixsite.com/index/cosmos

 

[LesOrr]

The Cosmos ADC

Thank you. This clarifies a lot.

I have been focused on my need for a better DAC first. I was missing the punchline about the Cosmos ADC, which does seem to have amazing specs.

Do you have one?

 

[staticV3]

Do you have one?

Yes.

 

[LesOrr]

Thank you again. Just the answer I was hoping for from this posting. I really appreciate it.

 

[johny_2000]

This term seems to be used frequently on the ASR site. Having spent many months 'restoring' a Tek DA4084 (in addirion to my AA5001) I am slightly familiar with SINAD. What is the specific relevance here?

SINAD (signal-to-noise and distortion) is the inverse of THD+N. Can read more in this topic.

I have been focused on my need for a better DAC first.

My setup has three DACs that I switch between depending on the application:
1. RME ADI-2/4 Pro SE (SINAD ~120 dB)
2. E1DA #9039S (SINAD ~125 dB)
3. Topping D50 III (SINAD ~125 dB)

Any of these can be improved for 1 kHz THD+N measurements with the E1DA Cosmos LPF to become a 1 kHz DAC with a 132+ dB SINAD, where all harmonics are -160 dB below the fundamental.

 

[johny_2000]

I personally believe that the APx555B is still unsurpassed in the Analog Domain where I have spent my life till now.

In terms of software features and an all-in-one solution, yes. In terms of hardware specifications of the ADC, DAC, and Analog Sine Generator, no. You can see it this review.
There are more advanced devices on the market that cost a fraction of the price. In my opinion, it's time for AP to introduce a new analog analyzer with better specifications, but AP doesn't publish roadmaps, so that's unknown.