Hi Kevin @kjlarochelle
Is the high-pitched sound a metallic, non-musical one – basically a sort of squealing sound? If so, the problem might be the same as the one I responded to in this post (which you should definitely read). I had this problem in one of my Lucky 13 harps but lucky for me I was able to get rid of it – the squeal, not the harp! 
I must admit that I was not very impressed with the overall quality of the sound from any of my Lucky 13 harps … As a result I have switched to buying PowerBender and PowerDraw harps from Seydel. And no, I do not work for them or get any benefits from them for saying this. In fact, I was hoping that the newer Lucky 13 harps might have improved from the old “first edition” models that I purchased some years back.
Regards,
– Slim 
Regards,
– Slim