Great sleeper amp. The circuit was a little different than the older EA-35T I worked on previously, but most likely because Gibson was just making use of surplus parts or whatever was lying around at the time.
Needed a general tune-up, and the amp had some horrific hum due to grounding problems. Once that was sorted out, I added control and screen grid stoppers to the EL84s and cathodyne PI, biased the outputs nice and HOT, and wired the external speaker jack so that plugging a cab into it will defeat the internal driver.
