It was great to finally get the preamp I purchased, but it won't work without the tubes you were supposed to ship. The UPS tracking number you sent me shows only that the billing information was sent electronically, but UPS never got the package from you. Please find the package and take it to UPS. The preamp looks great, but it uses tubes I don't have. Also, what is the toggle switch underneath the chassis? I look forward to hearing from you soon.