When I first started playing MTD Kingstons, I decided I wasn't going to change out pickups, nuts, nothing I'd done to my Spectors to get them playable...the basses are great, feel great, sound great...there's a lot of discussion on other sites about swapping out the pickups or the electronics on the Z series (not ZX) due to their allegedly wimpy sound. I think the stock electronics sound great, on both my Z5 and ZX...however...
...I just had a second battery installed in series to the electronics on my ZX #26(25)...WOW! WOW!!!!!!
So the guy who turned me onto that idea, he'd done it in his Z5...let me be clear here, I consulted with Mike, to the best of his knowledge, the electronics in the Z5 are designed to run at 9v, so he does NOT recommend or endorse modding those...but this guy's been running his Z5 for over a year at 18v with no issues, it sounds KILLER! His Z5 was sounding pretty close to my ZX in our opinion (myself, the store owner, and another bass player we're friends with who happened to be around...) I'll be upgrading my Z5 next...but the ZX is my main axe, so I wanted that done first...WOW!
Mike sent me the link for wiring up the ZX with the second battery, you can find it here:
http://www.bartolini.net/instruction...mb/AGDB918.htm
The diagram is for a different Bartolini circuit, but the wiring is essentially the same
Yeh, as most of you would know, the second battery doesn't make things louder...it gives you more headroom...I noticed especially more response in the mids...and the top end sizzles! Fat booty bass...the only other bass I'll want now is a ZX fretless! We played it in the shop through a guitar amp at first, and one of the regulars came to ask him when he got a bass amp in the repair office!!! Yeh, it's that huge a difference!
So yeh...if you have a ZX, or upgraded your Z5 or another MTD Kingston to Barts, give this a try...try it on your Z5 AT YOUR OWN RISK! But a $10 mod to improve the sound of a Z5 (which sounds great as is, IMO) is more cost effective then upgrading electronics/pickups IMO!