I just built two versions of Don Tillman's preamp. One is battery powered, the other phantom. They are pretty much identical. All the voltage readings are close, and the resistors and caps measure the same on both. The phantom one is way louder than the battery one, this with them running into the same preamp, same bass, same settings. I've tried changing the transistor in the battery version, but no difference. My question is this; Is it because there's more current available with phantom power? The voltage supply is higher (15v) but I've brought that down to the 9v with a resistor. Thanks for your help.