Just to share what i did... i'm playing a microbass too, HDB dweller, since my old Guyatone made in japan semi-vintage amp exploded. And i can't find the replacement National brand burnt power amp chip since its no longer manufactured.
Anyway its a bit crazy, but i have a spare Hi-fi speaker (Aiwa NSX... those mini-compo speaker) and i hooked it up to the 'speaker out' jack of my microbass, and i place the hi-fi speaker on my desk. Since the thing has a tweeter, a mid-range driver plus the bigger speaker (only 8" i think) the sound is quite... err hi-fi. nice slap tones to practice with. And since the Aiwa speaker is in a sealed, ported enclosure, the bass response wasn't bad too, even though i place it up on my desk. Cool. Sounds great when i play my CDs through the amp too, but since the microbass has no CD input, i made myself a simple passive mixer to mix bass + CD inputs to plug into the amp. Cost: $5. bus fare to sim lim tower not included.