Yes, the large file is the streamer OS firmware. The other is the direct dsd dac firmware update.
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After updating the latest two firmwares, I found that with dsd direct turned on, the external clock did not work. When I unplugged my clock cable, dac display âEXTERRâ, but the music continue to play
Turn off dsd direct, unplug the clock cable, and the music will stop immediately.
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I can confirm what KaWai says. It seems dsd direct mode is not compatible with an external clock on Gustard A26.
W
Did you upgrade the latest firmware ďź
There were 2 new firewares, one is for streaming part, one is dac part
Yes I updated both parts.
@jussi_laako :
Weâd need Gustardâs opinion. I think the whole thing works, but if thereâs no clock, the stream switches to the internal clock.
Iâd be surprised if the external clock is totally bypassed by the âDSD directâ mode (new firmware).
There does seem to be a noticeable difference between external and internal clock⌠even with DSD256 powered by HQPlayer.
In theory, the clock difference is less noticeable with DSD than with PCM 44.1⌠it seems to me.
If you ask me, what is the problem with internal clock? I personally donât care about external clocks. Nobody has been able to convince me that it would improve anything⌠But I can think of many reasons why external clock can make things substantially worse.
Not quite as good as Holo Spring 3, but not bad either:
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No, the thread (on Head-fi) would be that the new âDSD directâ firmware would be incompatible with the use of a master clock. The debate isnât about the usefulness of an external clock, and I share your doubts⌠even though Iâve tested it.
Or maybe thereâs a bug in the clock management of the AK4191 + AK4499EX chips. With âDSD directâ, the stream is managed solely by AK4499EX⌠and the master clock ?
When I turn on dsd direct mode and disconnect the clock line while music is playing, the music still continues. when I turn off dsd direct mode and disconnect the clock line while playing music, the music stops immediately.
âI think this is proof of dsd direct mode bypassing external clockâ
Both chips are always in use.
For 44.1k source, AK4191 needs 11.2896 MHz master clock and AK4499EX either the same or 22.5792 MHz.
For 48k source, AK4191 needs 12.288 MHz master clock and the AK4499EX either the same or 24.576 MHz.
This is half or less of what typical DAC chips use. Typical DAC chips need 22.5792/24.576 MHz clock minimum and many times 45.1584/49.152 MHz instead. ESS Sabre takes single 100 MHz master clock if you use itâs ASRC.
External clocks are many times something like 10 MHz which is not suitable for anything as such, but needs to be converted to the needed master clock rates through PLL.
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Thanks jussi,
I also found a problem about dsd direct. When the input source is 48k family and the output is dsd 128 256, the tweeter will make noise. You have to put your ears close to hear it. When you stop the music, the noise still appears, but I use dsd512 and there is no noise.
I have no problem with I2S enter with DSD256.
Have you same firmware number ?
Yes , same.
Maybe it is setting problemďź
It seems that 48x is making noise, but there is no problem with 44.1x. Are you also using 44.1 x?
Or was there have noise before updating the firmware , but I didnât notice it? I used 48x before upgrade the firmware.
I really donât know 
Jussi said that it is important to turn on dsd direct, so I now keep the output at 44.1 family, which also means that some filters cannot be used.
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Ok I ordered an SMSL DO300EX
Dual 4499EX and no IMD hump and selectable DSD filters
User Manual actually states the DSD Direct mode has around 3.7V RMS output , which is not the worst
If its measured performance is not broken I keep it. Otherwise will return for refund
I will measure it. Lets see.
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A comparison with your highly praised SMSL D-6 would be really interesting, as the DO300EX has all the relevant features for me (apart from DSD1024 ;). And it might even be a bargain during black week.
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Ha well the high praise for D-6 is specific to performance for price.
DO300EX is significantly more expensive than D-6
But lets see
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@dabassgoesboomboom
Can you confirm that the DO300EX uses 2x AK4499EX chips per channel? Maybe a picture from the inside?
Information about this is somehow not clear. Especially as the specs are almost identical to the D400EX which is twice as expensive and looks like copy&paste in the manual to me.
It doesnât look like that here:
