The BB is very quiet in a regular 1/4 inch input on a powered speaker (Bose S1) I use for small solo gigs. It has two xlr/1/4 inch combo inputs, I use one for the mic and one for the guitar, and an 1/8 inch mini stereo aux input.
The speaker runs on a battery.
I am trying to run the BB into the mini stereo aux input. The BB has nothing else plugged into it, it goes straight in. Here it is quite noisy. I have tried ground lift, a di box to match impedance, or using a mini stereo extension. I can turn the channel volume down and the BB volume to 95-100 % and you have to get close to the speaker to hear the added noise. The BB is pretty loud and usable this way.
It does the same using the BB headphone output.
I am trying to not use a separate mixer to keep things simpler.
Suggestions or ideas to make it quieter?