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SMSL M400 DSD CLICK

JohnYang1997

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I did some measurements the pop is always under -80dB referring to the 4V output. It's either just your unit or it will never be loud if not completely inaudible
-6a51f954d7f8cbbc.png
 

Pluto

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Thought experiment.

Can someone please explain what is so different about Linux that might, possibly, make it susceptible to this issue in a way that neither Apple nor Windows appear to be?

And how can you be sure that the issue, if any, is at the operating system level rather than the application level?
 

Tavy

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In my understanding Linux should natively support USB DAC and seams that some DACs are not built to support Linux specifications. Of course, it will be supported if the DAC vendor will provide a specific driver for Linux (like for Windows and Apple OSs) but , as Linux is used in almost all dedicated network streamers, it will not be easy to be installed. Therefore, people using standalone network streamers based on Linux are looking for DACs with native Linux support mentioned in the specifications.
 

zskyper

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I just completed my post to get started quickly with a good MPD configuration and Linux NATIVE DSD support, for MX linux simply use the Package Manager, search for antiX kernels and install version 4.19.83, reboot and enjoy native DSD1024!

and obviously I agree with Tavy, the D90 MQA is now returning back to its owner thanks to him for allowing me to test it during this last month. I invite all owners to report the problem to Topping.

to all the people interested send me a PM if you want me to open a dedicated topic related to using USB DAC with linux, I will be happy to help.
Cheers,
z
 

restorer-john

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I did some measurements the pop is always under -80dB referring to the 4V output. It's either just your unit or it will never be loud if not completely inaudibleView attachment 72124

So the previous testing showing 500uV spikes is a typical valid event? That translates to ~78dB below 4V. Trouble is, 500uV spikes on format/sample rate changes are utterly unacceptable in my opinion, especially if they occur at the start of tracks where people are riding the volume control or have it up from the last track or quiet fade-out.

Basically a D/A that makes transient 500uV spikes from the analogue output on sample rate/format changes that are unrelated to the actual musical content is a faulty design. Mute the output, rapidly ramp it up and down like D/As have done for decades.
 

w1000i

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to be clear this is important for YOU (Topping) not me, If you read carefully my reports I own a D90 Std which is perfect for me and which doesn't have any issue, I've also a D90 MQA kindly loaned by a pal for my tests because I was interested to find a workaround and fix myself this HUGE problem...unfortunately after making a lot of test since almost a month I cannot fix from my side but it's maybe easy to fix from the Topping firmware.

with D90 MQA connect in usb:

no issue with Mac or Windows with latest firmware/driver

Hardware using linux/alsa (rpi, desktop, streamer, network amp):

Switching from DSD to DSD at different rate is OKAY
Switching from PCM to DSD at different rate is OKAY
Switching from PCM to PCM at different rate is OKAY

Switching from DSD to PCM at any rate = HUGE POP so loud that seems to destroy your speaker! :)

So please check by yourself and fix it if it's possible... send me a pm if you need more info or need me to test something or whatever...


Mac and Linux use Linux core ( the same ). If mac is okay that mean D90 is okay with Linux core.

I believe you Linux system has issue.
 

JohnYang1997

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So the previous testing showing 500uV spikes is a typical valid event? That translates to ~78dB below 4V. Trouble is, 500uV spikes on format/sample rate changes are utterly unacceptable in my opinion, especially if they occur at the start of tracks where people are riding the volume control or have it up from the last track or quiet fade-out.

Basically a D/A that makes transient 500uV spikes from the analogue output on sample rate/format changes that are unrelated to the actual musical content is a faulty design. Mute the output, rapidly ramp it up and down like D/As have done for decades.
It will be hundreds of times higher if there's no muting....What dacs have you measured that don't have this behavior? It's also related to output offset. Since how long people are starting to think 0.5mV offset is unacceptable? If you have offset, when you switch on and off you get small spikes.
 
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JohnYang1997

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Thought experiment.

Can someone please explain what is so different about Linux that might, possibly, make it susceptible to this issue in a way that neither Apple nor Windows appear to be?

And how can you be sure that the issue, if any, is at the operating system level rather than the application level?
Linux 'should' behave the same as Mac OS as they both use UAC2. And should be the same as Windows 10 when no 3rd party driver installed. But for some reasons they are just different.
 

zskyper

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Mac and Linux use Linux core ( the same ). If mac is okay that mean D90 is okay with Linux core.

I believe you Linux system has issue.


LOL!!!!!!!!!!!!!! MacOS is based on NeXT operating system not related to Linux! Wiki is your friend!

and no, ubuntu, debian buster, Fedora 32, ArchLinux, Daphfile and the last one tested MX Linux do not have any issue.... I suggest to read carefully my reports be fore posting...
Cheers,
z
 

restorer-john

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Since how long people are starting to think 0.5mV offset is unacceptable? If you have offset, when you switch on and off you get small spikes.

Offset is one thing, if it is constant. And what gear doesn't mute on power off/on anyway? Rapid transient fluctuations of 500uV in a powered-up and operating source component is unacceptable in the normal course of user operation. This is a DAC sitting upstream from a whole lot of power gain. The output, whether it has an offset or not should at least be stable and not contain transient events. Have a look at what happens to a small woofer in a speaker at the other end- it's not pretty. Letalone if your customer has a DC coupled power amp- expect the DC protect to trigger instantly on those amplified transients.

There's plenty of gear that has unacceptable transients and it's just an indication of poor design. Plenty of big manufacturers are lazy with coupling, caps, DC offset and transient spikes so these products are not alone.
 

JohnYang1997

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Offset is one thing, if it is constant. And what gear doesn't mute on power off/on anyway? Rapid transient fluctuations of 500uV in a powered-up and operating source component is unacceptable in the normal course of user operation. This is a DAC sitting upstream from a whole lot of gain. The output, whether it has an offset or not should at least be stable and not contain transient events.

There's plenty of gear that has unacceptable transients and it's just an indication of poor design. Plenty of big manufacturers are lazy with coupling, caps and transient spikes so these products are not alone.
Unless you use DAC's own volume control you will never hear this. If you use DAC's volume control it's only audible not loud. Are you really thinking 500uV not 500mV? M400 used dc blocker before the switch hence reducing the pop between PCM files to tens of uV.
Now name a few companies/or model (a couple maybe) that doesn't use ESS based DAC and still don't have any pop(under 60uV). Benchmark use ESS chip and a dedicated ASRC chip. So I'd rule that out first. Older benchmark design maybe? Show me some measurements.
 

JohnYang1997

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Offset is one thing, if it is constant. And what gear doesn't mute on power off/on anyway? Rapid transient fluctuations of 500uV in a powered-up and operating source component is unacceptable in the normal course of user operation. This is a DAC sitting upstream from a whole lot of power gain. The output, whether it has an offset or not should at least be stable and not contain transient events. Have a look at what happens to a small woofer in a speaker at the other end- it's not pretty. Letalone if your customer has a DC coupled power amp- expect the DC protect to trigger instantly on those amplified transients.

There's plenty of gear that has unacceptable transients and it's just an indication of poor design. Plenty of big manufacturers are lazy with coupling, caps, DC offset and transient spikes so these products are not alone.
More on the offset bit. No you didn't understand. On/Off mute is on/off mute. It has nothing to do with offset. In contrast, when you unmute from on/off mute, you basically switch from ground to the dc offset value. If you think this is not acceptable then i agree. If you think this is acceptable then your statement about 500uV being unacceptable is hypocritical.
 

JohnYang1997

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So here's my own view on this. 500uV is acceptable but not ideal. Sub 100uV and perhaps under 60uV is more ideal to me. There's really pretty meaningful difference between 300uV, 500uV and 1mV. Most of the time it's really 300uV not 500uV. There are some DACs pop over 1mV all day everyday and nobody complains about it.
 

zskyper

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Following the statement of @JohnYang1997 the issue is from linux driver and not the DAC which is possible, I've done a new linux "audio" distro based on debian buster 10.4 (headless) by recompiling the kernel to get the latest 5.8-rc5, recompiling ALSA to get the 1.2.3 version, recompiling MPD to get the 0.21.25 apply all my optimization and the result is far better as several patch have been applied to audio since kernel 4.19.x but not good enough my pal still have pop sometime (it happens less often but still there unfortunately), the result seems to be very good if your usb DAC inject 50ms of silence pattern at start and end of signal, here my latest version of mpd.conf which may help owner of usb dac to get a clean sound with dsd native (ALSA USB DAC Native DSD) and dop (ALSA USB DAC DoP) and include a clean down sampling DSD to PCM (ALSA USB DAC Force 24Bit) for those who have pop. I still recommend the standard D90 vs MQA but if you need the MQA version you have here your workaround! ;)

hope this helps
Cheers,
z

linux Debian buster 10.4 or Archlinux recommended

on pi 4 plaform the 5.4.50-v8+ (ARM 64Bit) works great, available here:
https://www.raspberrypi.org/forums/viewtopic.php?f=117&t=275370
direct link:
https://downloads.raspberrypi.org/r...020-05-28/2020-05-27-raspios-buster-arm64.zip

Kernel version 4.16.x or 5.8 recommended type uname -a

MPD version 0.21.25 recommended type mpd -V

ALSA version 1.2.3 recommended type aplay --version

even on PI 4 platform a POWER USB 2.0 is ultra recommended,
connect the DAC and an optional IR Blaster USB for your remote control directly to the usb hub

D90 STD = use ALSA USB DAC Native DSD audio output

D90 MQA = use ALSA USB DAC DoP audio output

Bash:
music_directory "/media/music"
playlist_directory "/var/lib/mpd/playlists"
db_file "/var/lib/mpd/tag_cache"
log_file "/var/log/mpd/mpd.log"
pid_file "/var/lib/mpd/pid"
state_file "/var/lib/mpd/state"
sticker_file "/var/lib/mpd/sticker.sql"
user "mpd"
group "audio"
bind_to_address "any"
port "6600"
log_level "default"
restore_paused "yes"
auto_update "no"
follow_outside_symlinks "yes"
follow_inside_symlinks "yes"

# Normalization automatic volume adjustments
replaygain "off"
volume_normalization "no"
filesystem_charset "UTF-8"

#database {
# plugin "proxy"
# host "other.mpd.host"
# port "6600"
#}

#
###############################################################################
# Input
#

input {
plugin "curl"
# proxy "proxy.isp.com:8080"
# proxy_user "user"
# proxy_password "password"
}

# QOBUZ input plugin
input {
enabled "no"
plugin "qobuz"
# app_id "ID"
# app_secret "SECRET"
# username "USERNAME"
# password "PASSWORD"
# format_id "N"
}

# TIDAL input plugin
input {
enabled "no"
plugin "tidal"
# token "TOKEN"
# username "USERNAME"
# password "PASSWORD"
# audioquality "Q"
}

#
###############################################################################
# Decoder
#

decoder {
plugin "hybrid_dsd"
enabled "yes"
# gapless "no"
}

#
###############################################################################

# Audio Output

# optimised for DoP
audio_output {
type "alsa"
name "ALSA USB DAC DoP"
device "hw:1,0"
mixer_type "none"
dop "yes"
buffer_time "200000"
period_time "256000000"
auto_resample "no"
auto_channels "no"
auto_format "no"
}

# for native DSD
audio_output {
type "alsa"
name "ALSA USB DAC Native DSD"
device "hw:1,0"
mixer_type "none"
dop "no"
auto_resample "no"
auto_channels "no"
auto_format "no"
}

# force resampling DSD to PCM
audio_output {
type "alsa"
name "ALSA USB DAC Force 24Bit"
device "hw:1,0"
mixer_type "none"
format "*:24:*"
}
 
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