Rechargeable AA batteries for internal powering of pro audio gear have historically been poor performers. Alkaline primary cells, and more recently Li-ion cells, are usually the preferred cell chemistry. Fortunately, battery chemistries have evolved -- in some applications there is actually a runtime advantage when using the newer NiMH rechargeable batteries with portable gear versus alkaline cells.
There are two common rechargeable AA cell chemistries - NiCad (nickel-cadmium) and NiMH (nickel metal hydride). NiCad cells are still burdened by "memory effect", high internal resistance, and low initial voltage (1.2 V). NiCads are not recommended for use in Sound Devices products. NiMH, on the other hand, are a practical choice for cost-effective, reusable power. These cells are now the preferred type in high drain applications when you need to run on internal batteries. NiMH have a high initial voltage (1.4 V), low internal resistance, and don't exhibit NiCad's memory effect.
A good article on NiMH batteries is below. While it discusses NiMH batteries with respect to digital cameras, the power supplies of Sound Devices products are similar in current draw characteristics to modern digital cameras.
Most NiMH batteries have a paper surround circling the positive contact. Because early Sound Devices battery springs didn't make a reliable connection with the positive contact with NiMH batteries, the battery springs in all of Sound Devices products have been redesigned. The serial numbers below identify the Sound Devices units that have redesigned springs.
|HX-3||1901xxxxxxxx or higher|
|MixPre||0505xxxxxxxx or higher|
|MM-1||1801xxxxxxxx or higher|
|MP-1||0204xxxxxxxx or higher|
|MP-2||0403xxxxxxxx or higher|
For additional questions about battery powering of Sound Devices products, please contact us.