John, give B & K a call on Monday and ask for Jerry in Customer Service. He'll be glad to help you. Make sure that you know whether or not the unit has a toroidal or conventional "iron core" transformer as this will make a big difference.
There were actually three different designs that used that model number. The first ST-140 was rated at 70 wpc ( 70 + 70 = 140 ). These had the "old school" iron core EI type transformers. They then changed designs ( transformers, etc.. ) and bumped it up to 105 wpc. In the middle of production, they changed output devices. The biggest difference between the three models is between the early 70 wpc model and the other two models. Hope this helps... Sean
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