I used a Yamaha THR10C for years as my late-night practice amp. Not easy to find today, but a newer version - the
Yamaha THRII - is available. For quiet practice it's great. Has an Aux in for your computer/phone/mp3 player. The built-in "models" are largely guitar oriented, though there are a few built-in bass models that are fun for a minute. I generally found the "bass" or "flat" settings to be best.
Remember, this is a 20W amp, with 3" drivers, so it does not produce thunderous lows by any stretch. But it has a solid bass response, and you can hear what you're playing in open air, which I vastly prefer to headphones.