Slayer exciter(tesla coil) circuit modification to allow better audio input

So I have the circuit working with a kit but the only thing is the audio aux has this offset voltage or some high voltage output as the "input" so when I plug my phone to the tesla coil through the audio jack, there is strong interference. Can anyone offer a solution to the interference? The coil can sing fine, but this interference is really annoying making my phone glitch and I'm worried it might break it.
Thanks

Simon... this is on the  face of it a very weird circuit.  The Audio input ground does not go to the ground of the circuit and the audio live is connected directly to the primary of the Tesla coil.  I'm not surprised you're getting interference.  But could you post the kit instructions, especially if they have anything on how the circuit is supposed to work?  On your reply I might be able ot make some constructive suggestions.

Hi David, thanks for the reply.
There are no kit instructions which is a pity. I suspect to DC can actually get to the audio port since there is a capacitor on the ground of audio. Which leaves some form of AC to interfere with my phone. Thought the coil works fine and I can get music to play. Just phone is glitchy.

Simon.... well as a trial mod and one that should be fairly easy to do, try the following- connect the bottom of C1 to the LIVE on the audio connector (ie the top two points). You may ahve to change the polarity of C1 - the + should be on the gate of Q1 and the - on the audio connector.- Connect the Ground / Common of the audio connector (ie the bottom point) to a ground point eg bottom of C2I agree that no DC should get to the phone, but there would be fairly high level AC from the top of the Tesla coil primary.  with my above mod, the phone is more isolated C1 plus R1/R2.  This may not work at all though.  If your Audio connector is on a PC board, unsolder it and reconnect it as above with wires.  Let us know what happens, some cleverer guys might see this during the week :-)And just to check - J3 is where you feed the power in, right?  (ie not where you connect the phone?Cheers // David