Hello: I have a Tube Audio Design TAD 60 tube amplifier, the one built by Paul Grzybek. I need to have it serviced, am having trouble with biasing KT-88 tubes and a couple of other minor issues. I live in far Eastern PA (Allentown, Bethlehem) and am having trouble finding a reputable place to take it for service. Does anyone know of a good shop that can check it out and fix it up? Thanks.