jeanluca wrote:

I have a bluetooth device which is connected to my speakers. But I also have a cd player. I swapped the mini jack between the two, which was ok, but not optimal. So I bought a jack splitter.

Now, the bluetooth sound is fine (same as before) but the cd sound is very soft. If I remove the power source from the bluetooth device, the cd sound is as it was before

Why does this happen and how can I fix this?

The problem is that with the jack splitter, the CD player is having to drive both the Bluetooth player's output and the speakers, with the result you describe. You need to revert to plugging and unplugging each one or getting a cheap preamplifier to switch between the two sources.

John Atkinson
Technical Editor, Stereophile

Costs $49 and does just what you need - www.schiit.com/products/sys - and has been on our "Recommended Components" list for many years.

John Atkinson
Technical Editor, Stereophile