Quick question.. I couldn't find anything through my searches. I have an Ampeg BA115T combo (has a single preamp tube) that has a rather large transformer on it.. What is this transformer for? Is it an output transformer? (Which might be why I think this thing sounds so good (when it was working)).. The transformer is as large as the biggest transformer on my Ashdown LB30 all tube amp. I'm about to send the ampeg in for service as it's crackling and the volume is fluctuation and the transformer got me thinking. Just curious is all. Thanks!