Yes, correct - the SMPS powers the digital section, the analog section is powered by the transformer/linear power supply.
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Digital and analog grounds are tied to the metal case by some capacitors. these are required to comply with the electromagnetic compatibility regulations. There might be some spurious ground currents flowing through these caps. I will have a detailed look at this as soon as I find the timeā¦
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Yes I have, and it wonāt make any difference hereā¦ I have such in front of my HA 200. Results are the same. Isolation is the key, not the VBUS noise levels.
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This is good to know since I have the 7054-X coming in to try out with the DAC200.
Weird that coil whine problem. I havenāt experienced that with my unit. I keep it in standby mode when Iām not listening.
Happy New Year!
Youāre right! I missed the message in my JUNK folder (thanks Google!). The address was also different ā not what I was expecting. Well, next time I guess.
Iāll play with the idle time and see if that helps. Iāll also give USB a shot when I have some time to see if the popping still occurs and use that method for the wife and company, I2S just for meee.
Happy New Year all !
Currently listening to Audalytic (Gustard) AH90 - sounds sensational in DSD Direct with DSD 256x44.1k, ASDM7EC-ul, āWideā DSD filter on the AH90, as Jussi recommends for the A26 DAC.
Under 100kHz bandwidth I would AH90 it beats Cyan2 on most measurementsā¦ Cyan2 frequency response roll-off starts earlier and can make everything sounds nice and warm. AH90 (and ADI-2 AKM) are much more extended in frequency response.
Above 100kHz bandwidth Cyan2 and even RME ADI-2 (AKM) have cleaner analogue output. You get what you pay for.
With the DSD Direct firmware that you must install yourself (request it from Gustard) you must set HQPlayer to DSD256x44.1kHz. As Jussi has mentioned for A26 DSD256x48kHz results give loads of noise and distortion, so avoid it.
For the DSD noise hump, as Jussi has said for over a decade, this is non-music/non-signal correlated noise. So you need to listen to decide.
All my measurements are with the LAN input - it has NAA 4.4 built-in, so you donāt need to add cost of a USB isolator. Just make sure you follow Jussiās advice this past decade to use unshielded UTP ethernet cable as you canāt have any ground loop (this path anyway)
using sinc-S filter for its extended frequency response for measurements. When I listen I enjoy the default gauss-long/hires-lp filters.
It is definitely DSD Direct (with this correct firmware) because DSD256 direct vs non-direct look quite different and DSD256 non-direct and DSD128 non-direct look the same strangely. DSD256 direct and DSD128 direct look different, as they should. So Iām quite convince DSD Direct works correctly.
Cyan2 actually has a high IMD hump with CCIF vs level measurement. AH90 is one of the best I measured. My ADC (Cosmos) has its own IMD hump but Cyan2 boost the level of the hump around 30dB higher.
Which makes AH90 superb value for the price. Good job Gustard ! Iām definitely keeping this.
AH90 brand new is actually cheaper than the still very good used RME ADI-2 FS DAC (AKM), where I am. This makes it easy to recommend.
1kHz wideband shows DSD noise hump level more accurately than Pico:
The classic Jussi wider band sweep - clearly not as clean as Cyan2 and ADI-2 (AKM):
115dB SINAD (probably better in reality since this is my ADC limit I think):
No jitter - even better than my ADI-2 (AKM):
NID multitone is great:
Dual TDFD tones (NID) is great:
Triple tones (NID) great:
Frequency response with sinc-S filter very extended compared with Cyan2:
CCIF vs level: Small IMD hump but that is from my Cosmos ADC (ESS ADC) - most importantly hump is 30dB lower in level than Cyan2:
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Fantastic job. Thank you!!
Iām happy I bullied Gustard into this release.
This dac flew under everyoneās radar.
@jussi_laako will the A26 dac correction work on this?
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I was the first to post back in Oct 2023 
- but I didnāt want to risk it that early and be disappointed with DSD Direct, like with SMSLs and Toppings:
But you were the one that got them to update the firmware, so we thank you !
Just now I had an opportunity to loan one - I will definitely be keeping it (buying it).
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@Thomas_Rector - Iām curious what Gustard engineers can do if the spend more time and effort on improving the analogue stage
I havenāt seen many A26 measurements posted, I wonder if thereās much difference or small
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Iām just happy they did the dsd right on the akm chips lol.
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Maybe the only ones, with 4499EX chip ?
True
We still need to confirm the A26 right? But it looks like Gustard know what they are doing.
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Yeh would be nice to compare my same measurements above with A26.
I donāt know anyone that can let me borrow to measure though
This is a nice old post explaining how the AKM 4499 is quite different to previous AKMs.
This AH90 DAC definitely sounds quite different to my SMSL D-6 and RME ADI-2 FS DAC (AKM)! Obviously not just due to DAC chip alone, but it is one big variable !
This AH90 is a āfastā sounding DAC. More than my Cyan2 even. Transients, the attack.
Good to also note that Cosmos ADC is rather difficult load for the DAC output. So depending on the DACās current output capacity, this may affect the performance to some extent.
On my measurement rig I use 100 kOhm analyzer input impedance when doing measurements. It can be also switched into 600 Ohm mode which is good for testing the DACās output load handling capacity, but if I use that for anything I post, I mention it separately.
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It is important to also note that it was about the 4499EQ (single chip solution) which is different from the new 4499EX (dual chip solution). I have one DAC with the 4499EQ, SMSL M400. It behaves quite different from the 4191+4499EX combo. Although from DAC technology point of view they are similar, both using switched resistor array instead of switched capacitor.
IMD humps seem to be more common for switched resistors than switched capacitor, for some reason AKM changed the architecture. TI/BB and ESS are switched resistor too. While Cirrus Logic still remains using switched capacitor.
If you like that, you would certainly like T+A DAC 200ā¦
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I doubt it is similar enoughā¦ I donāt know what the exact differences are between the two from the DAC implementation point of view.
I think I have posted some? These are all from the USB input. Iām not sure if I used USB isolator here, if I didnāt, it could be cleaner with oneā¦
With 7th order modulator, using 5th order drops the out of band noise by 10 - 20 dB.
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@dabassgoesboomboom : So is the AH90 better than the Cyan2 or only better at itās price point or is it more a question of taste between these two?
I recently purchased my first amp dac: SMSL DO400. But reading this thread now I kinda think Iāll return it and get a Gustard A26. I know itās not the same price range, but it seems a better option for native DSD and also it has network adaptor (I assume itās roon ready).
Am I getting this right ?