SMSL DO400 Fully Balanced Audio Decoder & Headphone Amplifier

[nanook]

In post #277 I showed jitter measurements for USB, SPDIF and Toslink (measured with my PO100AK and the E1DA ADCiso).

@Roland68 did send me his PO100Pro on loan, so I could measure the I2S input as well.
As expected, this input shows some more spurs (the I2S input will likely not pass through some re-clocking), but all of these spurs are well below audibility to my opinion.

I had however expected that the DPLL setting has some influence. Within the reproducibility I cannot see any difference.

 

[timer1992]

I was planning to buy a DO400, but after seeing these threads, I noticed there isn't any firmware update on the SMSL website, which makes me worried whether the issue has been fixed or not.

 

[Longfellow78]

Can anyone please recommend a good budget power amp to pair with the do400 as a preamp. Perhaps the smsl a300? Id like smsl. Say my budget is £500 to £600, would I be better off with a £200 amp and £300 speakers, or £500 active speakers and no amp? Thanks! Bookshelf speakers BTW.

 

[David_M]

Can anyone please recommend a good budget power amp to pair with the do400 as a preamp. Perhaps the smsl a300? Id like smsl. Say my budget is £500 to £600, would I be better off with a £200 amp and £300 speakers, or £500 active speakers and no amp? Thanks! Bookshelf speakers BTW.

Active speakers are a design compromise of sorts imho. I would get a HQ passive speaker and a Topping low distortion amplifier to fit your budget. Never skimp on speakers as its the greatest tool that will cause the most change to your audio system.

 

[David_M]

I was planning to buy a DO400, but after seeing these threads, I noticed there isn't any firmware update on the SMSL website, which makes me worried whether the issue has been fixed or not.

What issue needs fixing?

 

[Longfellow78]

What issue needs fixing?

Maybe he is talking about the filters are wrongly labelled perhaps?

 

[Longfellow78]

Active speakers are a design compromise of sorts imho. I would get a HQ passive speaker and a Topping low distortion amplifier to fit your budget. Never skimp on speakers as its the greatest tool that will cause the most change to your audio system.

Hey. Thank that's kind of what I did. I managed to snag an ao200 mk2 for 25% off (£175) and a pair 2 month old mint condition dali Oberon 1s for just over half the new price (£217 in postage). So I figure I got £650 worth of kit for £400. Speakers coming next week.
Thanks.

 

[David_M]

Maybe he is talking about the filters are wrongly labelled perhaps?

Oh, they confuse me too. So just because I select a PCM filter setting on my Do400, e.g. Apodizing, but it could be another setting completely due to the messed up naming conventions???

 

[Longfellow78]

Oh, they confuse me too. So just because I select a PCM filter setting on my Do400, e.g. Apodizing, but it could be another setting completely due to the messed up naming conventions???

If I recall you should pick apodizing which is linear fast roll off.

 

[MicrosPL]

Oh, they confuse me too. So just because I select a PCM filter setting on my Do400, e.g. Apodizing, but it could be another setting completely due to the messed up naming conventions???

From what I understand Apodizing is in place. Measurements and explanations are here:

SMSL DO400 Fully Balanced Audio Decoder & Headphone Amplifier

Edit: Corrected comment for #8, Low Dispersion Dirac measurement and spectrum at Fs=44100 Updated slides for PCM filter options. According to my measurements the description of the PCM filters in the menu of the DO400 is wrong for several of the filter settings. Since people experiment with...

www.audiosciencereview.com

 

[timer1992]

Maybe he is talking about the filters are wrongly labelled perhaps?

What issue needs fixing?

Yes, but it's not the only problem, I remember there was a POP noise problem with XMOS chips? And the FW update program seems to be buggy.

 

[Longfellow78]

Yes, but it's not the only problem, I remember there was a POP noise problem with XMOS chips? And the FW update program seems to be buggy.

I think That was fixed you need to follow a guide. It's something to do with xmos drivers on the pc. It never happens to me after I did whatever it was that I found a guide on.
FW update is a pain but if yoy follow again one of the guides on here it works. Problem is there are no firmwares for download since v3. But it's fine if you are aware of the incorrect filter names.

 

[nanook]

This is the firmware update procedure:

SMSL DO400 Fully Balanced Audio Decoder & Headphone Amplifier

The FW update sequence that finally worked for me: - DO400 is plugged in (mains and USB), but power switch at rear of unit is "off" - install SMSL driver (not sure if it is really needed for FW-update) - unpack "DO400MCUVA3.rar" (contains zipped loader directory "ISP_PC_EN2" and hex file...

audiosciencereview.com

And this is the latest firmware v3, that worked for me:

SMSL DO400 Fully Balanced Audio Decoder & Headphone Amplifier

The FW update sequence that finally worked for me: - DO400 is plugged in (mains and USB), but power switch at rear of unit is "off" - install SMSL driver (not sure if it is really needed for FW-update) - unpack "DO400MCUVA3.rar" (contains zipped loader directory "ISP_PC_EN2" and hex file...

audiosciencereview.com

Still wondering why SMSL did remove this firmware (and others) from their website and doesn't react to the screwed up filter names in several of their products.
But it seems SMSL is still existing; a new firmware for the DO200 pro appeared on their website.
@SMSL-Mandy: Can you finally shed some light on this weird situation?

 

[nanook]

If SMSL does not react at all, the DO400 likely has been my last SMSL product. The DO400 is not exactly cheap and there is a competitor who delivers stunning DAC performance and a nice additional feature for 1/2 of the price - without a powerful HPA though.
At the price point of the DO400, I do expect a minimum of after - sales product maintenence.
The screwed up names of the filters definitely are a good enough reason to issue a new firmware to correct this.

 

[binaryblaze]

stunning DAC performance and a nice additional feature for 1/2 of the price

the D50 III?

 

[alexanderino]

And this is the latest firmware v3, that worked for me:

This still has one flaw: the 'Always On' setting needs to be enabled in order to ensure the start of a song (after a few seconds of silence) is not chopped off. My C100 has been fixed successfully, therefore I see no reason why the DO400 cannot receive the same fix.

 

[nanook]

Well, at least, I was able to do the update with this FW file and loader.
I was struggling to get the loader program start up at all - and I tried at least 4 different W10 laptops /desktops, amongst them a fresh installation on an Intel NUC Gen6.
Having the files in the locations where they are in this zip file finally worked.

I'm not even sure if the firmware on my unit was v3 already since the loader doesn't allow to read out the current version nor does it complain when "updating" to the same version as installed.
SMSL has to do some homework on this one.

 

[elso legey]

Well, at least, I was able to do the update with this FW file and loader.
I was struggling to get the loader program start up at all - and I tried at least 4 different W10 laptops /desktops, amongst them a fresh installation on an Intel NUC Gen6.
Having the files in the locations where they are in this zip file finally worked.

I'm not even sure if the firmware on my unit was v3 already since the loader doesn't allow to read out the current version nor does it complain when "updating" to the same version as installed.
SMSL has to do some homework on this one.

Hello, the SMSL D0400 has a new firmware update, at least posted in the English site. Unfortunately, there is no information regarding the fixes in this update, dated September 24th, 2024. May be one of our members will be able to tell us what fixes this update provide. I have installed the version V3 from this forum. Now they publish V1. This is very confusing. Thank you for the help.

 

[nanook]

I'm out the next week, so I can't try it out.
The unpacked subfolder is called "SMSL DO400 MCU_FW_v1.0_240925" -> I assume it's new indeed.
The last firmware hex file name was "IAP_DO400_1V0A3.hex", the new one is called "IAP_DO400_1V0A6.hex" -> sounds like it is v6 compared to v3
The actual loader program seems to be identical (creation date is identical).

SMSL used "zip" this time, which facilitates things.

 

[alexanderino]

Hello, the SMSL D0400 has a new firmware update, at least posted in the English site.

Thank you for the heads‐up. I downloaded the file from the SMSL firmware page and flashed my DO400 successfully; sadly, it still has not fixed the 'Always On' requirement to ensure the device does not cut off the start of an audio signal after a few seconds' silence.