I am a new hifi listener - so please forgive my lack of expertise.. I put together a system with the help of a friend. I’ve been listening to the Dynaco ST70 amp (purchased rebuilt in great condition on eBay with new genalex tubes) with Klipsch heresy speakers and an NAD preamp. All has been great for a month or so And then the Actual amp suddenly started intensely buzzing and rupturing the sound.) The sound sounds like it’s coming out of the transformers, and is more intense when I slightly lift/touch the unit. There is a possibility that I accidentally shorted it since I realized that a speaker filament attached to the C connection might have touched the vacant 4OHM connection next to it. Any ideas of how to remedy this? I have been trying to call/write to places that repair these amps to no avail. I can try to get some help possibly replacing the transformer if it needs replacement. Please help!