Testing some stuff today and broke out my 68 Plexi that the Plexi 50W 6550 model is based . Hooked it up to the isolation cab and created a preset to do some A/B tests. Model sounded nothing like the amp. "What did I break?!!" After about 15 minutes I remembered that my amp now has EL34s in it. Set the Power Tube Type to EL34 and proceeded to kick myself in the butt...