Quote from: albertorigoni on Yesterday at 06:42:48 AMThanks! But what would be the difference between battery and 5 pin supplier in terms of tone? thanks!

Don't think there is much (if any) difference in sound. If so, someone will correct me. Normally the ones with the 5 pins (series basses) are stereo but this one isn't.

I have an EvH 4 string myself (think it's a Deluxe because it has the same back wood as top wood and neck laminates). The one you posted is the second/later EvH model. I have the first (more classic looking) model. Really like it. Just posted this video below of it. I Have more videos of it on my YouTube. Good luck with the trade!
https://club.alembicguitars.com/alembic-basses-guitars/alembic-evh-signature-video-four-finger-slapping/

No difference in sound between battery and external PSU - except the battery won't die.  

My guess is that this bass was modified to include the 5-pin jack (maybe not done at the factory) so that the owner could easily switch between this bass and another Series I or II.  It is wired to use only the + side of the external supply (and that would be +15-20VDC) and to send the mono output signal down what is normally the neck pickup wire.

You certainly don't need external PSU, 5-pin cable, etc. as these instruments were designed and built to run off the one 9V battery.  It's an option for you, but it would cost you about a lifetime's supply of 9V batteries. 

We hope you really enjoy this bass!!
Jimmy J

I'll just add - although you probably already know - that the bass is "on" whenever the 1/4" jack is plugged in.  So unplug when you're done playing to save that battery.

Let us know how you like it!
Jimmy J