I got a set of the TBHZ (passive) to try out, hoping I'd get close to the tone I was getting in those 2001 TB+, but without the noise. Nope. They sound almost identical to the TB+ in my 2013.
When I pick up my BC Rich at the luthier from getting a new nut I'll ask if maybe shielding would help the noise from the 2001s. My guess is no.
Maybe try the EY black thunderbird replacement. I don't know what year they modeled them after, but they're relatively cheap. Their 60s-style pickups are pretty good. Separate neck and bridge with option for 9.5k or 14k resistance on the bridge unit.
https://www.eyguitarmusic.com/Eric-Custom-Thundbird-Bass-PickupBridgefor-Gibson-Thunderbird_p_2636.html
https://www.eyguitarmusic.com/Eric-Custom-Thundbird-Bass-PickupNeckfor-Gibson-Thunderbird_p_2635.html
Thanks. Knowing nothing about them, I have to assume they're going to sound the same as the TB+ and EMGs.
I think with you the issue might be that the pups have to operate while standing on their head? That can't be good.
Don't hit me!!!
(https://media.tenor.com/hUi05QbU6ewAAAAd/snake-hide.gif)
I COULD peel off the plastic covers and put new covers over the bottoms. Hmmm.......