Re: 18v Mod on EMG X Series?
1) A set can run off two batteries no problem.
2) The 18v mod on a standard EMG 81 increases the pickup's headroom - either you'll like it, hate it, or simply not care due to personal preference.
3) The 18v mod is not recommended for the x series. The 81x is meant to sound like an 81 with more headroom, but at 9v - making the 18v mod unnecessary. This is achieved by simply changing two resistor values on the preamp, making the 81x preamp -6dB from the normal 81 to reduce clipping. The output impedance is also at a lower 2K rather than 10K. I guess it may be worth trying, but I wouldn't expect it to sound great if you're looking for the EMG 81 sound.