Very simple way to limit amplitude of a feedback synth, in SuperCollider

sc_feedback_clamp

// Pass the signal only when its amplitude is below a given threshold.
(
a = {
	var source, clamp;
	source = In.ar(Server.default.options.numInputBusChannels);
	source = CombN.ar(source); // token effect: edit to add more fancy stuff
	clamp = Amplitude.kr(source) < \threshold.kr(0.1);
	
	Out.ar(0, source * clamp);

}.play;
)
//: 
a.set(\threshold, 0.01);
//:
a.set(\threshold, 0.05);
//:
a.set(\threshold, 0.001);