Gustard U16 - the first USB Interface featuring ESS USB chip
Jan 24, 2019 at 10:50 AM Post #467 of 1,697
My friend Magelan wrote them an e-mail and got following reply:

Dear Sir,
Thank you for your mail. We are aware that a particular customer in China is using the ES8620 in a new DAC.
This device was originally designed for Soundbar applications and has been non-preferred for new designs for several years.
We do not recommend this device for new designs and we are not supporting it here in Europe.
Sincerely,

David B***** "
---
They don't recommend this device, but it sounds awesome :)

A few days ago, after reading PitBul34's post above, I had conjecture about the shortage of U16 in the market: The chip maker did not want/encourage Gustard to make U16, so ....

My conjecture was not optimistic so I did post it. Now, I think that "the Gustard is revising U16" is a better guess.
 
Jan 24, 2019 at 11:22 AM Post #469 of 1,697
So AES can do 24/192. Is the issue with Hi-Res/DSD mainly with I2S? Has anyone sucessfully played DSD256 via I2S?

I tried to upsample CD wave files to DSD256 by foobar2000 + U16 connected to a DAC via I2S cable.
The results were good but this configuration had some glitches, the DAC unlocked once in while and generated light crack/noise. I felt that firmware 1.4 worked better than 1.58 and 1.61

In last few days, I have been upsampling CD wave files to DSD128 by foobar2000 + U16 connected to a DAC, and I have no complains so far.
 
Jan 24, 2019 at 2:43 PM Post #470 of 1,697
I received mine yesterday as well, on the third day after shipment to the Nordics.

It certainly sounds wonderful already but does not play 192 from Auralic Aries and spdif. Actually... it does, but for 15 seconds at a time. As reported by many.
 
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Jan 24, 2019 at 4:54 PM Post #471 of 1,697
So AES can do 24/192. Is the issue with Hi-Res/DSD mainly with I2S? Has anyone sucessfully played DSD256 via I2S?

did some testing with Aries -> U16 (different FW versions) -> AudioGD R7 (IIS input):

upload_2019-1-24_22-51-49.png
 
Jan 24, 2019 at 5:10 PM Post #475 of 1,697
Oh goodness, someone should pay you for that :wink:. I appreciate it a lot !

Some days ago, Gustard support had ask, if I could try another FW version.

so, trying to help and did it on the weekend and sent the xls back to support. no feedback yet.

FYI, testing was done only with Aries as a source (based on Linux). So test results for Win PC would probably be different.
 
Jan 24, 2019 at 5:29 PM Post #476 of 1,697
Some days ago, Gustard support had ask, if I could try another FW version.

so, trying to help and did it on the weekend and sent the xls back to support. no feedback yet.

FYI, testing was done only with Aries as a source (based on Linux). So test results for Win PC would probably be different.

Thanks for sending the data to Gustard support...

Hopefully the playback issues are not with the ESS USB chip. Obsolete chips usually have no support on field problems. The big question is can this be fixed via a future firmware upgrade?.
 
Jan 24, 2019 at 5:35 PM Post #477 of 1,697
Some days ago, Gustard support had ask, if I could try another FW version.

so, trying to help and did it on the weekend and sent the xls back to support. no feedback yet.

FYI, testing was done only with Aries as a source (based on Linux). So test results for Win PC would probably be different.

Thank you very much!!!

Your data indicate that the configuration "U16 (different FW versions) -> AudioGD R7 (IIS input)" has more OKs sans "Ch swapped"
 
Jan 24, 2019 at 5:50 PM Post #478 of 1,697
Thank you very much!!!

Your data indicate that the configuration "U16 (different FW versions) -> AudioGD R7 (IIS input)" has more OKs sans "Ch swapped"

I repeating testing using same playlist with test files.

Please keep in mind that IIS can support all bit rates, but other interfaces AES/SPDIF (XLR/coax/toslink/bnc) are limited. This is not an issue of the U16, rather a "limitation/standard" on Dac input side.

Typically AES/SPDIF (XLR/coax/toslink/bnc) are limited to 192khz/DSD64. In case above the limit of the DAC, I put "not playing (OK)".

However Hugo2 even supports PCM 352khz and DSD128, but only on coax input.

One more thing, testing was done only 1 or 2 times per test. Unfortunally some samplerates seems to produce unreliable results, e.g. 176khz, meaning sometime it plays fine, sometimes not.... :frowning2:
 
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Jan 24, 2019 at 6:20 PM Post #480 of 1,697
FYI, with all U16 fw versions file with 192khz seems not be <BitPerfect> transfered, at least on XLR/coax/toslink/bnc.

When Aries is connect directly to the RME (without U16 in between) all bit test are working!

Here some background for the RME results for TestType = BitTest, from the handbook:

https://www.rme-audio.de/download/adi2profs_e.pdf
"34.21 Bit Test

A bit test is used to check the playback path for unwanted changes in the playback data. Playback software can cut bits, add dither, or change the level - without these changes becoming noticed easily. A poorly programmed driver can manipulate bits, and a playback hardware could be both badly designed and defective (hanging bits, swapped bits). Even such features as proper channel assignment, left/right synchronicity and polarity can be tested by a well-made bit test. With a bit test, such errors can be detected and - more importantly - excluded.

How does it work?

Most bit tests take some time and are loud and unpleasant when playing through headphones or speakers. RME uses a unique bit pattern, with defined levels and pauses. This consists of only 400 samples (<10 ms), and sounds like a dull, medium-loud click - harmless for ears and equipment. The short, but efficient test sequence allows to check for the following changes and errors: Level changes, equalization, dynamic processing, polarity, channel swapping, sample offset, hanging or twisted bits, dither, bit reduction. The signal reaches the ADI-2 Pro via USB, AES or SPDIF/ADAT. The unit has three continuously running check circuits. If the test signal is detected correctly, the device's display shows a message: Bit Test 16 bits, 24 bits or 32 bits passed, depending on the detected signal. If the transmission path is not bit-transparent or bit-accurate, the signal only minimally changed, the message is not shown, the bit test failed. There is no error notice.

RME provides several audio files as free download: 44.1, 96 and 192 kHz in 16 bit, 24 bit and 32 bit. These files in WAV format can be played easily on Windows, Mac OS X and Linux. For ease of use (looping, players with fade in/out), the files contain the bit pattern several times. Runtime is about 4 seconds."
 

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