Amplug 2 Bass : It's the go-to solution for a reason

When you ask for recommendations for a headphone amp for bass, this is almost always the one you'll hear most about. There are good reasons for that.

Pros:

- Compact

- Cheap

- Sounds surprisingly good! It's very much on the reggae/dub/Motown side, and isn't hi-fi at all, but does a great job of that fat, deep tone.

- Built-in drum machine; one of its patterns is a simple metronome, too.

- Takes AA batteries, which means you can just rotate rechargeables through it.

- Auxiliary input means you can connect your computer or a phone to it (if you still have a phone with a jack socket). This has a separate volume control from the instrument, which is a nice touch.

Cons:

- Not robust. It's not outright fragile, but the plastic shell is clearly one place they saved on manufacturing costs.