A simple multi meter can tell you if there is a short circuit in one of the components or driver. put the meter in continuity check and put the leads (black and red) across the speaker terminals. If it buzzes its shorted, you can also read the resistance across the terminals if its low (few ohms) or zero it's shorted.
I would try another set of speakers if you have any see if that helps. or alternatively try another amp on the Tannoy's, this is after you check for short circuits.