Minimum wattage practice amp with s fretless

I don't se why a fretless would need any more power than a regular fretted bass. I would have to call that as nonsense. String condition, playing style (to include eq settings) and pickup strength would have a lot more to do with your output level.

To answer question, for strictly practice, any small amp will do. I have a little Fender rumble 15 that sounds great and far enough loud enough to jam with.

For recording I'll look at practice amps with more tone shaping and a direct line out as well. A sansamp pedal works ok to record through, but can get noisy based on eq settings.

Ampeg does make some great combos, just check their specs

 

I use a B15N for my practice amp. It works well whether I play fretless or fretted.

Same goes for my stage amp.

 

It is what it is, a bass practice amp.

 

I use a older (usa) Hartke kickback 10. It says 120 watts on the front. It works just fine with either fretted or fretless.