Amazon Basics 10 port USB hub

10-port USB hub with external power supply.

I've opened it because I thought no power on ports 4...10 when connected only to power adapter is a fault, but I think now this is normal behavior. 

As I cannot find precision description (only one I could find seems mostly wrong: https://www.ubuy.com.pl/en/product/87DHPNTA-amazon-basics-usb-a-3-1-10-port-hub-with-power-adapter-65w-powered-20v-3-25a-silver) here are few notes:

• hub does not work without power adapter (at least with my test with USB 2.0 cable), it is not even detected by PC
• ports 4...10 are not powered when hub is not connected to PC
• nominal maximum current: 2.4A for ports 1...3, 0.9A for other ports
• all ports are data-capable and have same sockets (USB 3.0-like)
• output voltage is slightly on high side: 5.2 V
• host port socket: USB-B SuperSpeed

3 screws under rubber feet

3 plastic latches

Overall quite solid construction.

3x VL817 USB 3.1 USB hub from VIA Labs Inc. - company specializing in USB technology. Chip itself is on the market from May 2017.

As each hub has 4 downstream port, my guess is these chips are cascade-connected.

Each chip has own 25L512E SPI Flash chip (512 kbit).

HU39002V1 V1_0 2017/11/30

Two "big" DC/DC converters with "AVICUH" marked chips.

LED next to each port activates when there is data connection.

Each of 1...3 ports is accompanied by chip with "5AAAJ" markings.

Each of 4...10 ports has G547G1 chip - 90 mOhm power distribution switch with 1.5 A current limit and overcurrent output.

Power supply: Chicony A16-065N2A, 20 V, 3.25 A - seems to be decent quality.

Trust Mauro USB headset

Trust Mauro (17591) USB headset, retail price ~$20.

Problem: weird sounds from left earpiece (not correlated with played audio), slightly disturbed sound from right earpiece.

Rather big in size in-line controller: volume, output mute, microphone mute.

Sound card (chip with scrapped markings) inside USB plug. Plug itself is glued together but can be opened by prying (with some damage).

Cause of the problem: mismatched connections between USB part and controller part. I think this was factory error, probably partially caused by not so clear PCB markings (for example there is "M-" and "M/-" contact pad).

Build quality is worse than with Trust Roha - headband is thin and little creaky, ear cushions are less soft. In-line controller is large and its weight can be felt when e.g. it drops from the table.
Probably too much bass (same as Trust Roha), but not as muddy - they sound better than Trust Roha.

On the other side microphone is quite noisy. It seems that this noise depends little on USB connection - it was higher when I was using extension cord.

One weird thing is that sound card emits some heat - not a lot, but this is still unusual for this type of device. I'm not sure if this is not a problem of my particular item, but otherwise it seems to work correctly.

Trust Roha 24188 USB headset

Inexpensive USB headset with microphone.

Fault: no sound from left earpiece, intermittent sound from right earpiece.

Earpiece disassembly: two plastic pieces are press-fit together with ear cup held in between. No glue is used.

Volume control + mic mute on the cable.

Sound card / electronic plug is held inside USB plug.

Fault: broken cable between controller on the cable and headset, possibly in more than one place. I've had to cut off about half of the cable from the headset side.

Overall build quality seems quite nice, with stable cushioned headband and pleasant ear cups.

Sound quality coming from headphones is somehow muddy and little unnatural, but might be acceptable.

Microphone might be little quiet but in general should work.

T12 OLED soldering iron

My latest purchase, T12 OLED soldering iron. Few reasons why I have chosen this model:

• (obviously) compatible with T12 tips which became very popular due to great price/performance
• I think that it would take less space than variant with base station and with longer cable it is kind of portable
• it is quite cheap (< $25 with 3 tips and shipping) as power supply is not included
• I already have spare good quality power supply (at the moment: http://commonemitter.blogspot.com/2020/02/hama-00039729-regulated-power-supply.html, although it is overkill)
• I completely do not trust cheap AC/DC power adapters that are included in similar sets - ones I've seen are unearthed and (as is pretty common for unearthed switching mode power supplies) probably have some leakage and thus are dangerous for soldered components 

Offer from aliexpress allowed to choose tips - I went for BC1, BC2 and JL02 and I'll probably use BC1 (cone with tip cut off at 45 deg angle and 1 mm diameter) most of the time.

Motion for standby power down is detected with some kind of mechanical pipe-shaped sensor. There is audible metal ball or something like this bouncing inside this pipe when soldering iron is in position close to horizontal.

BA9H13, LM358 and some microcontrolled with scrapped markings.

Default menu language was Chinese, though I've switched to English in few tries. Menu has one or two positions more than described by seller, so firmware is probably still developed and might change over time.

Some drawbacks I've found so far:

• I wouldn't mind if handle + tip would be slightly shorter - it's about 2 cm longer than my previous AC-powered soldering iron
• as handle has glossy and smooth surface it would be also slightly slippery - lens-like part of the handle does not bring any value
• as handle is made of hard plastic - it might be prone to cracking if dropped

Mi True Wireless Earbuds Basic 2

One of the earphones was damaged, strongly heating up when charging.

Apparently opening these earphones is possible - perhaps they can be called serviceable. This came to me already opened.

XM2000

Antenna is missing - probably damaged when opening.

These earphones (PCB markings: T29-XM2000-NTC-V1.2) are very similar to RedMi Airdots 2: https://www.qucox.com/redmi-airdots-2-teardown/ (T29-XM2000-V2.1).

I do not like the sound of these earphones. I had only one in my ear and from what I see this changes perception of the music, but I would describe their sound as flat, with bass missing. Maximum output volume seems also lower than e.g. with Trust Primo Touch or Libratone Track Air+. Probably because speaker is relatively small, only 5.4 mm in diameter.

Mechanical switches instead of touch buttons are a plus in my opinion.

Earphone lasted respectable 4 hours and 20 minutes playing audio with maximum volume from BT 4.0 phone.

It was also compatible with old Nokia 113, Bluetooth 2.1 EDR.