@raabje You need to follow the Vcc trace from the USB port to the 4056 pin 1, I think the diode is in series. I'm thinking the Vcc goes from the usb to the diode, and then from the diode to the 4056 pin 1, but you need to verify this. Looking at the Z1 micro usb connector, you could bend and...

@raabje Yes, those are the power supply pins. You need to look at Z1 circuit, from your PCB photo, it looks like there is a diode, before the power goes into pin 4, probably for reverse voltage protection. I'm guessing a good place to solder the USB power would be in that 10uF capacitor legs...

@raabje You can't connect the USB power supply wires to the battery. There's an IC marked 4056 on the other side of the PCB to receive the USB power and to do the battery charge. Search for TP4056 datasheet to know how it works. Before the repair, you need to de-solder the battery wires from...

I don't have any information about Zishan, but there were a combination of factors, the ICs shortage (still affects STM32 soc/cpu) and AK DAC factory burned in a fire. Recently AK started shipping some of the affected DAC models and has redesigned AK4490R, AK4493S, etc. I took a look at some...

If you are in EU, in AE shop the tax is included in price now. There are no customs costs if tax is included, but I read some local mail companies could charge a small fee. In AE app checkout (just before paying), will say VAT included. I think I've read in the new EU import tax rules (changed...

Out of curiosity, I searched AE for "Zishan Z2", but can't post the link, because that seller is banned here. (Probably old stock, but I'm guessing.) Just googled now, I haven't follow any audio news for a long time. Looks like AK is coming back with some production, I read they have some new...

Hi, Yes, I found the photo you want, not the best quality, but it shows the connections. At the time I used 400 Ohms earbuds and didn't need a buffer, so this was only a test and I removed it. If you decide to put it, don't make those long wires, just solder it in place with short wires. Also...

Is it ok to use 15nf (=0.015uF) ? I usually see schematics using 100nF (=0.1uF) ceramic in parallel with 10uF ceramic or more. (Connected between ICs power lines and GND and near those ICs power supply legs).

I also have one "smoking cap" previous experience by my mistyake. At least we could see happens to the caps, with smoke and swollen, it's a another level of reality experiencing vs reading/theory. :) BTW big caps just blow with a big bang sound and make a mess, that append in a closed computer...

So 1rst cap was bad and 2nd cap was good and was deliberated soldered with wrong polarity. Let us know if the 3rd cap keeps working.

You need to investigate that further with a multimeter. As you know, putting the multimeter red probe in the (+) capacitor leg and the black probe in (-) cap leg (with circuit power on), must always give a (+) positive multimeter voltage reading. If you get a negative voltage reading it means...

Regarding the L and R channel switch, there is a bug in Z3, when I pause the music (I use FLAC), sometimes after I resume play the channels are switched (I don't have Z4). A way to get the bug in z3 is to pause and resume a few times pressing the center button.

@Setmagic I look forward to read more about z4.

Z4(2xES9038Q2M) looks like a good upgrade to DSDs(2xES9038Q2M). Zishans ak449X are no longer available. I do like modded Zishan AK449X sound a lot, there's no sharp mid range here, but I agree that we all have personal preferences. Never heard ES9038Q2M so can't compare. I agree that...

@maxxkur Nice, thanks for sharing. Out of curiosity, what's the red wire ? Is it for measurements? Please take a look at your private messages, I sent you one.