I was surprised to be hit by exactly the same issue today after not having used my dwarf for a while and plugged my phone’s TRRS headphones into it (I’ve done that many time before without any issue so it might not be the culprit), but also changed and then reverted a few options in the advanced menu and enabled and then disabled the experimental usb audio gadget.
The problem is that headphone audio seems to be the subtraction of output 1 and 2 duplicated on the two channels. So if I have the same signal in both outputs, I have exactly nothing. Wiring from input 1 to both outputs is totally silent.
A single wire connected to either output 1 or 2 while the other is not connected to anything gives me audio on both sides of my headphones.
If I insert a mono volume control before each output, I can hear something if they don’t have the same gain.
Current install is 1.13.5.3315
I have tried another set of headphones (my TRS in-ears) and the problem is the same. I have the issue only with the headphone output, not the 6.35 one. I have tried to play with the setting that copies the mono-output buffer to unused channel.l without success.
Now something even weirder: if I plug a stereo 3.5 cable into my dwarf’s headphones output, then its other end into a splitter, then my headphones into one of the two output of the splitter, and connect the splitter’s other output into the aux input of my small NUX Air Amp while this one is connected via usb to the same PC as the dwarf, the problem disappears… And this is true even if the NUX is turned off !
As soon as I disconnect the NUX from the PC, the problem reappears…
So it looks definitely like some hardware grounding issue of some sort…
Ok, so further investigation seems to confirm this.
I get normal audio in my headphones if I ground the headphones by using a splitter and touch the jack plug of my guitar cable with the sleeve ring of small 3.5 cable plugged in the splitter.
Hi @jon ! Would you be able to give me some instruction about how I could possibly repair this issue if that is caused by the headphone socket having it’s ground connection broken a I suspect it, please? Could it be as simple as resoldering it properly?
This is interesting to read because I have a similar case in support and it’s nothing like I saw before.
I would say that it doesn’t hurt to open the device and go with a solder iron and solder retouch the connecting point (I think you have the skills to do it, no?)
Let me know if that solves the issue. Maybe the other user is facing the same.
I am not sure when I am going to be able to do it as I am swamped with stuff at the moment.
But the other user can already try touching the sleeve of their headphone with the one of the input jack and see if it solves the issue (see my picture above).
Not sure if I am the other user who ran into this issue, but I got my unit sent back and fixed, now output1 is the left channel and output 2 is the right channel and they don’t cancel each other out.
It has other issues due to having different outputs (with and without cabsim) being sent to the headphones, but at least the canceling out bit is solved, so I can’t really test this anymore
Perviously (when it was in the state i have described), output1 was sent to left and right channels, the very same way. With the replaced unit output1 is on the left only and output2 is on the right only. So depending on your configuration your headphone jack may be pretty useless.
The headphone jack simply mirrors the 1/4" jack outputs at headphone level.
If you are sending completely separate signals then indeed it’s not so useful as a headphone monitor or something.
In that sense the use-case for this output is somewhat limited. Having an additional codec (or one with multiple outputs) would’ve been more complex and more expensive.
Hey @Azza,
Sorry for the delay. To be honest, I guess there’s something, but I can’t really find it at the moment.
Anyway, @James did a great job and the MOD Dwarf is quite painless to open in order to access the headphones port. The PCB even has a little cut to help you put your finger and pull the PCB.
You just need to be careful with the cable that connects both PCBs, as far as I remember. But it’s nothing that you would easily damage.
Not sure if it helps, but I have taken it apart once before I don’t remember anything about it, it wasn’t particularly painful.
I have a picture below about it being taken apart already. It seems that you only need to remove the nuts from the back (jack barrels) and the 4 screws at the bottom and you can lift up the whole thing.
hth
