I have a Euro 4 with PJ emgs. I have been reading about the 18v mod. Would adding an addational 9v battery in serieres affect the tone pump pre amp? Thank 4 your advise in advance.
FWIW: Don't know anything about the Spec. Manufacturer recs are the ones to follow. I personally haven't been able to tell any benefit from adding a battery to a pre that ran fine on 9v. In fact I've been more inclined to run an 18v pre on 9 if it sounded fine.
The best solution for the tone pump is an EMG BQC system http://www.emginc.com/displayproducts.asp?section=Accessories&categoryid=33&catalogid=141
well I had a home made jazz with EMGs, I tried the 18v instead of the 9, guess what: it made the bass sound more present, more punch and clearer highs, or maybe my ears were fooling me