Sony WF-C500 Teardown by 52Audio

52Audio has published their Sony WF-C500 teardown and with this model being a lower end device, there are some differences versus the other WF headsets from previous years. I will try to point some out, if anyone catches any others I missed, please leave them in the comments.

First looking at the exterior, there appears to be some extra plastic (yellow circle) on the edge of the earbuds in the teardown. I am not sure if this is an isolated incident or if the build quality is generally like this for the WF-C500 and other Sony devices made in Vietnam. The factory is an OEM company, and not a plant directly owned by Sony, so perhaps quality control is not as high as in Malaysia.

Source: 52audio.com

An interesting design feature is the hole for the microphone, which has been designed to minimize wind noise. For anyone who owns a pair, how is the wind noise versus other Sony earbuds and other brands? Does the new design work? I wonder if we will see something similar on the WF-L900 once it releases and other future WF headsets.

Source: 52audio.com

 

I forgot to mention the IPX4 rating (thanks for the reminder in the comments), but it does look like there is something on the earbud seam, could be glue but not sure if this is enough. There is no rubber or seal around the charging pins, but they are directed towards the face and should avoid direct exterior water but perhaps not sweat. Personally I would not subject these to too much water.

 

Looking at the inside of the charging case, it does not look like there is much extra space. but a wireless charging coil would fit, but it would need to connect directly to the board like in the WF-1000XM4. I do not think it would be possible to just add a charging coil to the board since it would be lacking the necessary components, but one could attach a wireless charging pad via the USB type-C port and cover the unit in a silicone case. 

A more drastic option would be to somehow try and connect the wireless charging pad USB connection to the PCB board on the unit. But I am not sure that is possible and I have seen reports of some Chinese made Qi charging adapters catching fire. So I would not recommend this route.

Source: 52audio.com

Anyways, the battery is a Li-ion 621733 type. The numbers represent the dimensions, 6.2mm x 17mm x 33mm. The capacity is 300mAh/1.11Wh, rated at 3.7V. Googling for this battery type does show different battery capacities, with some even offering more than 300mAh, but these are on alibaba or aliexpress and I would bet that some of these larger capacity batteries are fake. But assuming you could get your hands on an authentic 621733 type in larger capacity, say 350 or 400mAh, then swapping it in should give you more recharges. But I am not sure if the battery protection board would have to be swapped over, or the one attached to the new battery would suffice. The only downside would be longer time to recharge the bigger battery.

Btw is anyone able to explain to me why a 300mAh internal battery is only able to provide 1 recharge for 2 earbuds with 70mAh batteries (total of 140mAh)? If the case was 100%, charged and you recharged completely discharged earbuds, would they use more than 140mAh to recharge them once? Is the recharge from the case battery not 1:1 to the earbud batteries? Are there losses, like from heat? If anyone can explain or link a video, that would be great.

Source: 52audio.com

Now onto the headsets, first looking at the top part with the button, we can see the antenna below the plastic button. The antenna does not appear to be printed onto the plastic like the WF-1000XM4 but instead looks like a ribbon cable antenna. I would imagine this is for cost savings, but if something would break, replacement would be much simpler here.

Source: 52audio.com

The PCB on the topside has the antenna connection and the tactile button. On the bottom left we can see the connection to the driver. The board looks to be held down by 1 philips head screw.

Source: 52audio.com

The top of the board has the main Bluetooth SoC, microphone for calls and the charging pins. The amount of components is comparable to the WF-XB700 but a lot less than say the WF-SP800N or even WF-H800. One thing I will point out, even though the model name for certifications is YY2952, the board still has the old HDX-2952 moniker, meaning internally Sony probably still uses HDX.

Source: 52audio.com

The driver is 5.8mm, as specified on the product specification page and also when 52Audio measured it. I understand this is a lower end device, but I feel Sony could have used a larger driver. One issue I noticed is that the driver is glued in or covered in some kind of epoxy to keep it in, so replacing it would require more effort. Likewise the wire connections look a bit fragile, so if you are taking it apart, be careful as not to rip them.

Source: 52audio.com

Looking at the internal battery, we have a soft cell pack rather than a coin cell like in previous models. The capacity is 0.27Wh at 3.85V, which is about 70mAh. I am wondering if the plastic holder was not present or modified, if a CP1454 sized battery would fit. It would provide more battery life, 85mAh, but again not sure how the fit would be.

Source: 52audio.com

Finally turning to the Bluetooth SoC. The WF-C500 uses the Airoha AB1562M with a production date of week 19 2021, or May 2021. The WF-XB700 also used an Airoha chip, the AB1552, but this new chip offers a few improvements and benefits over the one in the WF-XB700.

Source: 52audio.com

The first major change is that the new AB1562 supports Bluetooth 5.2 which could end up being upgraded to LE audio in the future once the specifications are finalized. The SoC also features "New generation echo cancellation and noise reduction schemes improved audio quality of the voice calls". The WF-C500 has no NC, but perhaps the SoC also helps reduce environmental noise from calls.

The DSP is a Cadence HiFi Mini®Audio Engine with a maximum frequency of 208Mhz. The flash memory is now 32MB, negating the need for a dedicated flash chip on the board. While the SoC does support noise cancellation, the AB1562M version does not. 

Compared to the AB1552, I think they are comparable with regards to audio performance and even NC, but I suspect the AB1562 could be built in a newer manufacturing process and should be more efficient. For those interesting, specs for the AB1552 are here and the AB1562 here.

It will be interesting to see how the upcoming WF-L900 will be built and if it will have more components or less in order to save on costs and battery consumption. Even the WF-1000XM4 uses one main PCB, so I would imagine we will see the same on the L900.

If anyone finds anything else interesting in the teardown, leave it in the comments.

Teardown source