I would like to share some observations regarding SATA-to-USB adapters.
Two types of adapters
There appear to be two kinds of SATA-to-USB adapters: Those who mainly use USB as primary power source and those who mainly use an external DC adapter as primary power source.
The former kind (USB as primary power source) appears to use a boost converter which converts the 5 volts of the USB port to 12 volts in order to supply the 12 volt SATA rail, while directly supplying the 5 volt rail from the 5 volts of the USB port. Since the 12 volts are generated inside the adapter, the use of the external DC power is optional. It is able to power low-power devices such as solid state drives and 2.5 inch HDDs directly from the computer's USB port, but requires an external 12 V DC power supply for high-power devices, meaning 3.5 inch HDDs and optical drives.
When the SATA adapter with USB as primary power source is disconnected, the connected device powers off entirely, apparently because both the 5 V and 12 V rails are supplied from the USB port, while the external 12 V power supply only supplies the 12 V rail and not the 5-volt rail (after voltage buck conversion, meaning reduction).
The latter kind (external DC adapter as primary power source) supplies both the 5V and 12V SATA rails with the external power, and the 5 volts rail is generated by buck-converting the 12 V from the external DC power. This makes hard drives and optical drives spin without being connected to a computer USB, however, low-power devices still need to be supplied through the external power adapter and can not be operated from the standalone computer USB port.
So far, both kinds of adapters worked well with internal hard drives and solid state drives, but optical drives by TSSTcorp and Pioneer appear to have trouble with the latter kind (external DC adapter as primary power source). After using the drive for some time (varying from a few seconds to a minute), it gets unresponsive and stuck. Optical drives by HL-DT-ST appear to work fine with both kinds of SATA adapters.
I am not the first one to make this observation. Someone posted it to Club MyCE (sadly defunct since 2022) in 2017. Here is a post by the user "ceym6464" that might explain it (source):
(I hereby release this post, excluding the quote, under Creative Commons Attribution-Share Alike 4.0 International.)
Two types of adapters
There appear to be two kinds of SATA-to-USB adapters: Those who mainly use USB as primary power source and those who mainly use an external DC adapter as primary power source.
The former kind (USB as primary power source) appears to use a boost converter which converts the 5 volts of the USB port to 12 volts in order to supply the 12 volt SATA rail, while directly supplying the 5 volt rail from the 5 volts of the USB port. Since the 12 volts are generated inside the adapter, the use of the external DC power is optional. It is able to power low-power devices such as solid state drives and 2.5 inch HDDs directly from the computer's USB port, but requires an external 12 V DC power supply for high-power devices, meaning 3.5 inch HDDs and optical drives.
When the SATA adapter with USB as primary power source is disconnected, the connected device powers off entirely, apparently because both the 5 V and 12 V rails are supplied from the USB port, while the external 12 V power supply only supplies the 12 V rail and not the 5-volt rail (after voltage buck conversion, meaning reduction).
The latter kind (external DC adapter as primary power source) supplies both the 5V and 12V SATA rails with the external power, and the 5 volts rail is generated by buck-converting the 12 V from the external DC power. This makes hard drives and optical drives spin without being connected to a computer USB, however, low-power devices still need to be supplied through the external power adapter and can not be operated from the standalone computer USB port.
So far, both kinds of adapters worked well with internal hard drives and solid state drives, but optical drives by TSSTcorp and Pioneer appear to have trouble with the latter kind (external DC adapter as primary power source). After using the drive for some time (varying from a few seconds to a minute), it gets unresponsive and stuck. Optical drives by HL-DT-ST appear to work fine with both kinds of SATA adapters.
I am not the first one to make this observation. Someone posted it to Club MyCE (sadly defunct since 2022) in 2017. Here is a post by the user "ceym6464" that might explain it (source):
You want to stay away from any adapters when trying to recover data, and interface with the drive as directly as possible with a real IDE or SATA controller. Otherwise, you’re introducing an unnecessary translation layer which may not always relay your commands to the device the way you want it to. Most of these adapters have their own ‘hardware read retry’ counter (may be controllable with vendor-specific commands, if you’re lucky), so you’re easily multiplying the wait time on bad sectors by an order of magnitude.
(I hereby release this post, excluding the quote, under Creative Commons Attribution-Share Alike 4.0 International.)