It just occurred to me that the filter changes and phase are handled directly by the chip. Thus, there should not be a relay click when they are changed.

I have not tried an earlier firmware to verify this.

I sent Paul my information via email but my situation matches stereophilus with the exception of item # 11. It was morning, and I don’t like falling down when lunch is served…

I am another negative example. Never noticed any tuning noises or pops (I use a preamp).

1/ PWD serial nbr and unit number: PWD-B1-9F001454 MkII upgrade PM2-BO-1L0036

2/ Bridge PWB-A-OI0011

3/ bridge firmware version 0.2.14i

4/ PWD firmware version 2.4.3

5/ Ethernet. (Toslink used for TV sound but resolution does not change.)

6/ Pre amp, balanced

7/ No Tuning noises, pops or static. Heard white noise a few times when testing WaveStream (usually fixed by stopping and restarting the song).

8/ No tuning noise or pops with any version

9/ No resolution issues (other than the universal problems with Wavestream high res, etc.)

10/ No noises while switching to higher or lower resolutions other than relay click

11/ None of Gordon’s business

12/ Nothing that occurs to me except, like Elk, not sure if filters are actually changing as there is no click (don’t recall if there ever was a click as I have pretty much just left it on auto and never heard much of a difference).


No problems at all

1 PWD #0284455

2 Bridge yes

3 Bridge firmware 0.2.14b

4 PWD firmware 2.4.3

5 Connection ethernet

6 Pre amp balanced

7 No noises of any kind

8 No previous DAC versions 2.02 or 2.20 had noises

9 No problems playing any resolutions

10 No switching noises other than relays

11 Probably drinking

12 Nothing else to add other than being for fortunate experiencing no problems


If you are on PWD 2.4.3 and Bridge 2.13c could you please install 2.14b on your Bridge.

Then please test if pops are the same. Just a hunch that I wish to rule out.


here it is:


SN D0-21052674




USB and i2s

Pre amp, Single ended

No noise of any kind,

same for all prior FW

All resolutions ok

No switching noises

Yes love Coke Zero

But I checked the mute stuff reported in jcleveland’s last two paragraphs and sure enough I have them too.

So, perhaps overriding certain functions improved the SQ?


I still gets the pops when using the bridge after upgrading bridge firmware 2.13c to 2.14b. The pops when changing tracks on the W4S server on the i2s input seem to be less frequent though… Go figure.

What was your hunch?

1/ PWD-C1-01026362

2/ Bridge

3/ 2.14f (I think)

4/ 2.4.3

5/ Ethernet and toslink

6/ Integrated or direct; SE

7/ No adverse noises

8/ No

9/ Once had a small pop changing SR - long time ago

10/ Yes, see 9

11/ Of course!

12/ I seem to have a ‘lucky’ unit - nothing like the problems reported by others.

If you are on PWD 2.4.3 and Bridge 2.13c could you please install 2.14b on your Bridge.
Then please test if pops are the same. Just a hunch that I wish to rule out.

here it is:

Same result except that 0.2.13c is more stable and sounds better.

Thanks for the good information. What I see in the responses, is that those of you with preamps do not here noises. I would like to request your help with answering 3 more questions related to pops:

1) Where do you have the volume set for the DAC? If it is at 100, would you please lower it to 50 and then raise the gain of the preamp to normal listening volume and see if pops become evident?

2) Does the mode matter (Native, NativeX, SR)?

3) As an experiment, can you remove the preamp, run the PWD directly into the amp, and see if you hear pops?



Dave, I'll try number 3 when I can, since 1 and 2 don't apply to me.


1) My DAC volume was always set at 100. When I turned it down to 50 and boosted the preamp, I began to hear faint (but distinct) pops when changing resolutions (especially when switching from 44/16 to a higher res or vice versa; changes, e.g., from 96/24 to 192/24 seemed less likely to generate an audible pop).

2) Happens with NativeX and Native but not when SRC is set to 192 (no sample rate changes in that case so not a surprise).

3) Same except pops a little louder (I need to turn the PWD down to about 35 for a direct connection)

We suspected the preamps might be masking the issue. Don’t know why we didn’t try this earlier.



1 - Dropped DAC volume to 25, turned preamp up as far as it would go. A light pop was occasionally audible when changing resolutions.

2 - Behavior is the same regardless of mode.

3 - Integrated amp - GCC 250.

The only pop/static discharge sound I hear is right after a track is finished playing.

And nowhere else. Constantly after the track is finished playing, but, not all the time, only randomly.

The pop is always in the same location every time, right after the end of the track.

This occurs at any sample rate or filter setting.

I do not have any noise other than this, as others have described. Zero noise when switching selections of sample rates, input, filters.

Pop sound only at the end of the track.

PWD PWD-B1-9G005679

Bridge PWB A1 0J0443

MKII Upgrade PM2-BO-2DO948



Noise started after MKII Upgrade

PWD volume is always at 100

As a test, I removed my preamp, fed my PWD into amps, use PWD to control volume, without fail, pop exactly at end of track.

Thanks for the good information. What I see in the responses, is that those of you with preamps do not here noises.

Au contraire mon frere.

I use a single ended preamp and hear pops on resolution changes. Yup. I do, as do others.

@vhiner1 Thanks for this info. Can we get a bit more? We need to know

1. What version you’re using

2. What sample rate and does this matter or change the pops at all?

3. Use the front panel PS Power Button and try muting and un-muting your DAC. Does this make a pop?

4. Does it happen on any input? Please experiment

5. Does it happen with any source? Please experiment.

Thanks for the help.

FYI, my testing (original results with preamp and no pops noted and subsequent response to Dave’s request) was done with FLAC files and my system info is on the first page of this thread. All my testing was with the Bridge.

I experience loud pops when
I switch to a higher resolution. There are no other SQ anomalies that I can hear.

Unit: PWD-C1-0J027909

Mark II PWD Upgrade

FW: 2.0.2

Shunyata XLR and Mora James RCA digital cables to PWT

No bridge.

CT5 preamp

Ocassionally there are no pops when switching down from a higher resolution....always occurs when switching up.

Sometimes when I switch to a higher resolution there are as many as two relay clicks and a pop. Other than this, the unit works well (phase shifting, volume etc. I also cannot get an sd card besides the one sent with my broad upgrade to work properly during an update. If a fix is found, I would like an SD card with the latest stabile firmware sent to me; I have followed all the instructions for downloading to the letter. A free, pre- loaded sd card for those with malfunctioning firmware seems to be reasonable expectation since we know so few are having difficulty with 2. 4. 3. Thanks!


I posted this a few clicks earlier on this thread.

I am using 2.0.2. I am unwilling to install 2.4.3 because I cannot format an SD card that will function with my unit, even though I have followed formatting and downloading instructions to the letter. I know several others who have experienced this quirk. The only SD card that works is the one you guys sent me with my PWDII update. Because this card contains the firmware that sounds best in my system, I am not excited about removing it from the only working SD card I have.

I would be willing to try the 2.4.3 update if you guys would send me an SD card preloaded with 2.4.3 and promise me that I can easily revert back to 2.0.2 if the new firmware does not work or the SQ is not as good.

In the mean time, I will try the mute and input options you suggest and report back.

@mgn You suggest 2.2.0 works. Can you do us a favor? Go to the version info screen with 2.2.0 installed, the one that works for you, and write down the version number of the firmware as well as the CPLD number. Please email me directly or post it here with the info.

Thanks for the help.