The PB223 is for powering phantom powered microphones with 48VDC. Since the unit uses a 100KHz switching power supply there is no audio noise generated. The PB223 has output pull down resistors so it will work with any mixer. The PB223 is identical to the PB23, except it powers two microphones rather than one.
 
Specifications
Phantom voltage: 48V
Connectors: 2: Male XLR, 2: Female XLR, 1: 5mm DC input jack
Power Input 12 - 18 VCD (Rolls PS27)
Size: 5.45" x 2.875" x 2.25"
Weight: 2 lb (.9 Kg)
Current drain 40ma nominal one mic 15vdc
Utilizes a switching regulator for stable voltage performance
Power condenser microphones requiring phantom power
Operates on the included Rolls PS27 12VDC adapter
High frequency switching power supply to eliminate noise