Sounds bad. Most "breadboard power adaptors" suffer the same problems as "Vin" on the Arduino.
When we refer to a "wall wart", we mean a 5 V one with a USB connector. To connect it to a "breadboard power adaptor" you need a male-to-male USB cable to connect it to the USB socket on the adaptor. The "Barrel jack" is like that on the UNO/ Mega - quite useless. 