He's definitely been quoted as saying he used a rented active p-bass on Dookie, but from the quote it's not clear whether that was the only bass he used.
Here it is from Bass Player:
There are several distinct eras of Dirnt tone. What was your setup on Kerplunk?
My secret weapons were Yamaha G100 guitar heads from the late ’70s and early ’80s, which I used to play through my custom Mesa Boogie 6x10 cabinet. That’s what started my love of 6x10 cabinets. I used that Yamaha and 6x10 on every record except this one, and occasionally, I’ve used an Ampeg, too.
On
Insomniac, I played my Gibson G3; you can really hear it on
Kerplunk and
Insomniac. It’s distinctive, like on the intro to “No One Knows.” On
Nimrod, that was mostly my ’69 P-Bass and a ’52 Precision, I think.
You seem to favor passive basses.
Some guys have gotten great active sounds, but that’s just never been my world. Actually, on
Dookie, I played an active P-Bass that I rented from SIR, because my basses were broken and thrashed from touring. That bass had P/J pickups, but the way I had it set, it might as well have just been a P-Bass. It went through an Éclair Engineering Evil Twin tube DI, and then my 6x10, and an Ampeg SVT. I had the Ampeg for the low end and the extra sub-lows, and then the 6x10 for that classic punch.
Between the transition from there to
Warning, I started working with Mesa Boogie, and that’s when I ended up using two 6x10s sitting on top of an 1x18. I was also using a Sunn head, and I had Mesa make me a 4x10 cabinet that I could use for the high end, to get that click, like tic-tac bass.
