What kind of 4-pin power connector is this, displayed in this (exemplary) image? Are there any specs of the maximum current and voltage it is designed to provide? (Unfortunately this was the best image I could find.)
This looks like a 4-pin mini-DIN connector.
Electrically, the connector itself is usually the least sensitive part of a supply. However, mini-DIN is designed to save space, so you can easily run into its limits.
The actual specs depend on the model; you always have to the check the datasheet. (For example, the CUI MD-40 is rated for 1 A at 100 V, or 2 A at 12 V.)