Headphone Jack Too Short?

I had the same problem and I REALLY pushed the plug in - Got a very faint output in only one side. Took my Nexus to a Wireless store and they said they see this a lot. They showed me that all my earphones had only 2 bands. He showed me a 'real' 3.5 earbud that had 3 bands. They worked GREAT. He said that the Nexus 7 was not backward compatible with with the older (2 band) buds. I don't know if this could be the problem but this started happening when I downloaded the new Android 4.3. Perhaps there is something in that caused the problem.
 
I had the same problem and I REALLY pushed the plug in - Got a very faint output in only one side. Took my Nexus to a Wireless store and they said they see this a lot. They showed me that all my earphones had only 2 bands. He showed me a 'real' 3.5 earbud that had 3 bands. They worked GREAT. He said that the Nexus 7 was not backward compatible with with the older (2 band) buds. I don't know if this could be the problem but this started happening when I downloaded the new Android 4.3. Perhaps there is something in that caused the problem.
Thank you. Three bands are necessary, whether you are using the mike function they are sold as for or just trying to listen. My two band buds tend to cut sound off and switch back to the speakers if pushed right in. And if you do get them to work by fiddling, the sound is mono. There are lots of three band headphones out there for ?3 which are not labled 'for Nexus 7' and give excellent stereo. Nexus need to publicise this.