Recently got a 1967 Fender Vibro Champ shipped back from repair. It sounds great but there is some buzz. The tech is well respected but here is the issue. With a tele, strat, and les paul, there is a buzz that sounds like a ground issue. If I turn the volume down on the guitar it goes away. Also, if I turn the tone down about half way it goes away as well. When I plugged in my 1960's Tiesco Delray, there was no buzz at all. Is this something I just have to live with or does this sound like a problem with the input jacks on the amp. Of the two input jacks they both act the same. Thanks.