EMG active pickups and EQs are powered by a standard, rectangular 9 volt (IEC 6LR61/NEDA 1604A) battery. We recommend normal alkaline batteries (Eveready or Duracell, for example) for best results. These are the same batteries that you would use in an effects box or wireless unit and are widely available.
We do not recommend the use of rechargeable batteries in EMG systems. Although they are compatible electrically, typically you must fully discharge these batteries to preserve long life, which can be problematic in normal usage.
You can externally power your EMG system, although we do not provide parts for this option. We don't recommend doing this, however, as the you will require extremely high quality power filtering to equal the performance of a regular battery. Since the pickup is the very first stage of your system, it's particularly sensitive to noise.