The unboxed modified Hiface shows the Power Supply connectors at the side. These have since been replaced by leads with PS connectors on their ends. These can be connected to an external 3.3V DC supplly. I use two 3.3V LiFePO4 batteries (& can supply these) for the best low noise supply I know (see the battery mini-review http://sites.google.com/site/hifacemods/home/announcements/batteryreview.
This sounds exactly the same as the boxed version with exactly the same modifications applied. The only difference is in the aesthetics & operational aspects. There are no switches in this configuration so turning on/off requires connection/disconnection of the power supply. Leaving the unit turned on all night when using batteries as the power supply, will probably drain one of the batteries. Draining the batteries below 2.5V is not recommended & can shorten the lifetime of the batteries (15 years estimated when used normally). Recharging the batteries requires them to be disconnected from Hiface & connected to a charger.
The hole in the top of the casing is an I2S modification that was experimental & is not now provided.