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
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
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...
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.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.
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.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?
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.
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.
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.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.
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.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.
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:*"
}