How much is the amplifier worth right now?
Something clearly is causing a short that is heating up and drawing excessive current.
Typical possible repairs
If you're talking about the amplifier smoking, and let's just say the cause is those wound coils ...then that's probably the power transformer.
You most likely would need a new amp because if had it repaired you're looking at a minimum of over $100 just to look at the amp (applicable towards the repair if you authorize it). Typically there'd another sizeable chunk for cost of the transformer.
However, that isn't to say the cause is transformer...I was just citing an example. If it's one of the power chips, then that could end up over $200 as well with labor and parts.