Here's answer to your questions.
1. We bring in this problem while solving pop noise of AK4493.
Edit:
The unit I have has minimal clicking, only power-up, power down and track pause/play.
Track change has small click in speaker but none in the relay. Seek has no click at all either inside the box or in speaker.
I don't use the included USB cable or power supply, but I get consistent results with Windows (W7 with 50ms buffer and ASIO driver) and MPD+ALSA (I tried only Moode Player using generic USB device setting).
--------------------------------------------
Hi there,
First post here!
I'm waiting for my unit, and stumbled across this issue a bit after ordering. I had a quick look at the board pictures and was hoping for a bit of insight. The problem may be simple or complicated for a user fix, depending on how it is implemented and how intrusive it actually is. I have a week or so before the unit reaches me, and want to start working on a fix proactively in case I end up needing it.
While I understand the reason for the clicks, my question is whether both relays are muted in exactly the same way, or is the issue limited to a single relay. Also, whether they shunt the signal via resistor or are in the actual signal path like a series switch.
I read a lot of feedback on relay clicking but none on any interruption of the sound stream either on headphones or on the line output, which means the duration of the offset is probably lower than required for audible stream interruption - and maybe that they are shunts (though I can't see the shunt resistors - solder side?), but I wanted to be sure (if you are at liberty to share). I am assuming the third relay is a toggled gain switch, and all three are wired to the ST microcontroller?
Not sure what levels of pop we are dealing with so any insight you can provide would help - is the offset the kind that will kill speakers/headphones/eardrums, or just an irritating click (few mV).
I can wire together a JFET-based soft mute with a 5-6 components and replace the relay, which would not be too difficult (I think relay is through hole so a compatible daughterboard should be doable) - if the pop is excessive. I also do not plan on using the headphone output so that's one less thing to worry about. Relays do have better S/N than soft-mute circuits, but obviously excessive operation of the muting circuit mandates a soft-mute.
Whenever I have removed soft-mute I find only small noises when changing sample rate or powering up/down, nothing significant worth worrying about. However hard mute is almost always required when the offset/pop/transient is very large (>50mV), and requires relays. Additional question would be whether this is unique to dual mono 4493 due to larger imbalance because of mono mode operation. But we can do nothing about that at this point except increasing the driven load, which will worsen performance.
I like the Dx3 a lot because it has an amp too though.
