ZD3 L/R Phase (or Timing?) Issues

[hatwearer69]

My ZD3 is acting a little oddly. It functions perfectly the majority of the time but occasionally the left and right channels will sound as though they have been pulled apart sideways by about 10 feet. This will happen roughly every 15-20 minutes. I haven't timed the interval but I plan to take a video of the system while it's playing in order to see if the issue happens on a regular interval or not.

My suspicion is that there is an issue with some clock signal internal to the DAC that is causing a phase imbalance or time delay between the two channels. This happens across every input and it does not seem to matter which analog output is being used; balanced or single ended. I have narrowed the issue down to the ZD3 by changing out amplifiers, interconnects, and sources.

My next troubleshooting steps will be to test the ZD3 with another 12VDC PSU - though I don't think this is the issue - and to try changing the operational amplifiers as I have the launch edition ZD3 that was supplied with upgraded op-amps. I will update this post with the results later this week.

Has anyone else experienced an issue like this? Otherwise I love this DAC for its feature set (HDMI ARC + CEC!!) and impeccable measurements.
Thanks in advance!

 

[hatwearer69]

My initial testing using audio tracks and a video camera yielded results but the issue was difficult to make out due to the monaural mic of my phone so I decided to make up some RCA breakout cables and connect the DAC to my oscilloscope.

The test setup is as follows:

1. REW running on a windows PC acting as a signal generator. 1Khz Triangle wave.
2. Digital output to the ZD3
   1. For Coaxial testing a known functioning Schiit Eitr is used to convert USB to Coaxial digital
3. RCA output cut and connected to oscilloscope probes.
4. O-scope: Channel 2 is Right. Channel 1 is Left.
5. Phone to keep watch while I was up and about.

I chose to use a triangle wave to make any shift in phase that much more obvious. In the images you will see the two channels at different levels. There is no DC offset. I have set the oscilloscope to offset the wave forms on the screen so that both waveforms can be seen clearly.

I was incorrect in the original post: It appears that only some of the inputs are affected. So far in my testing the USB and Coaxial inputs are rock solid with no issues. Given that it is highly likely that the Coaxial and Optical inputs are running through the same IC I think it is safe to assume the Optical input is also functioning correctly.
I was able to recreate and capture evidence of the problem while testing through the Bluetooth input. The phase shift in the right channel seen on the o-scope is in-line with the delay and soundstage smearing that was heard through speakers. The images below are the REW waveform generator settings and a GIF of the exact moment the phase shift occurs.



I'm not sure how one would go about fixing this. It's nice to know that most of the inputs work as they should but I purchased this item specifically for its HDMI and Bluetooth inputs which are affected by this issue.
Would Fosi Support care to weigh in?

Thanks.

 

[mades910]

I have similar problems. Occasionally the sound is odd, something like a corruption for about one second, a sound like “ttrrrrrr” Sometimes something like you describe: a sudden “move” of the sound to the side. I’m wondering if it’s a problem of the dac itself and planning to return it and get another one. Is brand new. 3 days of use now. Connection: hdmi arc to TV Problem either with TV, apple TV (sporify and amazon music), imputs. What shall I do?

 

[BlushResponse]

My HDMI (arc via tv) is having the same issue as Mades, short bursts of "trrrrrr", plus occasional echo (very short, like half a second). I've installed the new firmware update, but it didn't help. Can we get a reply from someone on the Fosi team?

 

[wing537]

Same problem here with the ZD3 and it seems to only happen with the HDMI input connected to TV. The weird sound would only happen randomly for a split second or two so it's nearly impossible to catch it on a recording to show the issue but it happens enough that it's getting annoying.

I also have a Wiim pro plus connected via optical for music but it doesn't seem to have this problem at all when using this input.

I've tried updating the firmware that was posted in this article: https://support.fosiaudio.com/hc/en-us/articles/41533797670041-Experiencing-digital-glitches-or-echo

However, my ZD3 already came shipped with the 1.06 firmware, which is the same as the one posted in the article. So updating the firmware didn't seem to fix anything.

I just submitted a support ticket. So let's see what support would say.

 

[fcosta]

Same issue here with 2 ZD3s. 2 different tvs via HDMI. Have not noticed issue with opt or usb. Have not tried bt or coax.
Any word from FOSI? Really love it otherwise but this issue really kills the experience. I hope they look real hard at this issue.

Frank-

 

[fcosta]

Should we try v1.07? https://support.fosiaudio.com/attac...CBx9NUB/?name=update_1.0.7_zd3_dpll_value.bin

 

[joergasmussen]

I have observed the same. But not often. I use USB.
Since November 2024 until now I have heard it a handful of times.

 

[SWL3600]

I have two ZD3's. One uses coax the other uses optical. I have the same exact issues you guys have described on BOTH ZD3's.

In doesn't happen that often but seems to be happening more frequently lately.

Any help with this problem is much appreciated. Otherwise, I love all my other Fosi gear!

 

[wing537]

I have two ZD3's. One uses coax the other uses optical. I have the same exact issues you guys have described on BOTH ZD3's.

In doesn't happen that often but seems to be happening more frequently lately.

Any help with this problem is much appreciated. Otherwise, I love all my other Fosi gear!

See my other post here:
https://community.fosiaudio.com/threads/zd3-intermittent-echo-and-buzz.5424/#post-6044

Download the zip file I posted there and try updating the firmware. The Google Drive link I posted there was given to me by Fosi Support. Follow the instructions included in the zip file and see if it fixes your issue. It fixed the issue I had.