I have built my first SSTC a while ago now and have been running it perfectly fine using an external clock signal at 100% duty cycle at high power. But now I want to add an interrupt circuit to be able to play music on it, and thus need the coil to run on a feedback signal. So I attached a CT at the primary and successfully got a clean enough feedback signal that was able to drive the coil. But the problem is that the moment it strikes an arc to ground, the coil shuts down because the power supply shuts off (its a switch mode PSU I used for low power testing). I'm not sure what the problem is, is it that the frequency of the feedback will decrease when an arc strikes ground and basically cause the primary to become a short?

Also, my feedback circuit consists of the CT output put across a shunt, and its voltage amplified by a Darlington array, which creates a good enough square wave, so why is a Schmitt trigger always used, does it have some other advantage I don't know of? And the other feedback circuit I've seen is the use of a 4046 IC, which I've researched a bit, but still don't really understand why its used. Is it because the 4046 will continue to output the default 'center' frequency if the tesla coil feedback crashes and goes outside of the lock range? I'm just looking to find the best and most stable way to get a feedback signal and any help will be appreciated.
Thanks!