If you want to travel light - and like the sound of your bass DId - get a good DI like the Avalon.
If you want to travel light and want a degree of tone shaping, your options are the Sansamp, EBS MicroBass II, and the Radial Bassbone.
If travelling light isn't really an issue, get a valve preamp like the Aguilar DB680, Ampeg SVP-CL, Alembic FX1, Demeter or the Warwick Quadruplet, depending on what sound you're after. I think they're almost all discontinued.