In my living room I have a small midi system that I've plugged a phono-stereo headphone jack cable into with the intention of listening to Spotify by plugging my iPhone into this and using the Spotify app. However, whenever I try this, Spotify plays the first track I select then immediately goes offline. Within seconds of unplugging the phone from the hi-fi connectivity is restored. Does anyone have any ideas on this one? I'm using an iPhone 4 running iOS 5.1 and Spotify 0.4.23.11.g86a7d473.