Just got the AC1 Rhythm VOX Bass amp as a gift from my wife. The volume through the amp seems very low, and unless I turn up the drive, I get no sound from the bass at all. (The rhythm seems normal, and the passthrough runs independantly of the bass volums.) I can live with this if it's normal and expected, but if not, then I need to know so I can exchange it for one that works. Thanks!
The first thing to try is a new set of batteries in the amp. If you have an active bass, maybe the battery in the bass needs replacing. I haven't tried the AC1 but you'd think that it shouldn't be working the way that you are describing.
I'm using both batteries and an AC adaptor. It works a little better with the adapter. The bass is passive, but I'd hope that wouldn't make a difference.
In that case, you might have an issue. There are a number of demos on youtube, they should give you a good indication as to what to expect from the unit in terms of volume level.
Passive shouldn't be a problem. If you had an active and the battery was low, your signal would be low going into the amp which might have explained the issue. Did you test it with headphones to see if it works the same way?