I need help. I have a Boss Katana Head and a Roland JC-40 Jazz Chorus  amp. What I want to do is to switch between both amps by using an A/B box. So far so good...
In addition to this I want to use both headphone jacks together by using  only one headphone. That is, I don't want to switch between 2 seperate headphones which would be annoying, wouldn't it?
Can someone tell me how this works? Do I need any device in between the headphone and the 2 phone jacks?
Thank you.  
A similar type of A/B box would work.
Of course you have to look for headphone jack size (3/16 ?).
Stereo or mono makes little difference, unless you can find an A/B box that let's you get creative.
Then it could be awesome.

You could also use a standard box and get adapters if needed.
Last edited by CodeMonk at Jun 3, 2017,
You need a stereo headphone mixer.