Need help: No left output from external audio card

[johan931]

Introduction

Hello. I'm having trouble getting sound out of both of my speakers. I tried seaching for a similar problem on this forum (and google) but with no luck. I hope you guys can help me out.

 

My setup:

Software:

OS X 10.8.2

Logic Pro 9.1.8.

 

Hardware:

Macbook Pro (Late 2011 Model) (1.5 year old I think)

2 speakers connected with a 3,5mm minijack cable

a 3,5mm minijack to audio jack (?) adapter (not sure about the names, but basicly big and small sound cables)

The M-Audio Fast Track MK II External USB soundcard

A Microphone (not really important since the issue is not exlusive to recorded material).

A Midi-keyboard.

 

The problem:

I only get sound from the right speaker when using my external audio card.(I get sound in both speakers when I just plug them into my computer directly) Mono or stereo tracks doesn't make a difference. When I pan to the right, the sound disapears. It seams the right output is not going anywhere, while the left output goes to my right speaker.

 

What I have tried so far:

Checking these forums

Making new projects and project from templates

Deleting all logic preference files.

Using other speakers/headphones.

 

Final details:

This mac have previously used logic succesfully

My external soundcard have been used with succes on another computer few days before this problem occured

This problem have been there since I installed logic on this mac

 

Outro:

I hope you guys can help me, or at least point me in the right direction because I have no idea what to do next.

[triplets]

I suspect like the mini to 1/4-inch adapter is not stereo (TRS) or just faulty. The mini jack should have two black stripes on the pin. If the 1-4 inch adapter is female it's hard to tell if it's TRS or not, gotta trust the product's specs.