DJ mixer-headphone problems

[Audiojunky13]

Dear Oricle,
I have designed and built a 2 channel DJ mixer.
I take the headphone feed (to the headphone amplifier) from the main output amplifier before the main output volume pot. The problem is when the 2nd channel is selected for the headphone (i.e. to cue up the next tune) some of that signal coming out of the main output. This is NOT supposed to happen. Has anyone out there got an idea why this is happening? Answers greatfully received.

 

[Osvaldo de Banfield]

We need some explanations like how are you mixing the signals, equipment in use, etc.

 

[JonSnell Electronic]

The headphone amplifier should be fed from each selector switch after the pre amp and before the mixing, otherwise called pre fade signal. Doing that, every channel selected will produce headphone signal, so if channel 2 alone is selected, only channel 2 is produced in the headphones.

 

[Audiojunky13]

more detail

Thanks for the replies so far. I have added a block diagram to help and a little more detail of the problem.
for example:
When listening to Ch1 through thte main output one needs to cue up Ch2 using the headphone. BUT, when Ch2 is selected on the headhone some signal can be heard through the main output, this then becomes worse and distorted if a connector is put in the headphone socket. Removing the main ouput feed to the headphone amplifier does not solve the problem. Any ideas?

 

[JonSnell Electronic]

Sounds like you have a ground position issue.
Ensure the headphone ground is common to the vol control and pre amp ground.

 

[Audiojunky13]

wrong diagram

 

[Audiojunky13]

Thanks John,
I thought it was a ground issue too, I will investigate further.