Checking for crossover and driver issues

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.  

Use dayton DATS to do an impedance sweep on both.

Ideally include speaker cable to ensure they aren't shorting

Thanks.  I just connected the Kensingtons to my NAIM ATOM and they work perfectly.  I’m told by my tech that means there is no issue with the speakers.  What an amazing little machine the NAIM ATOM is BTW. It’s normally running Tannoy Mini Autographs in my bedroom.  

smart circuits sometimes do stupid things out of nothing.

get rid of smart stuff and everything works

That DC offset circuit itself could be at fault. Amplifiers cannot be diagnosed over the phone with non-tech customers. Don't waste your time troubleshooting, send it for warranty repair.

Just to be sure, check to see if the wall receptacle is operating normally. 120VAC on the hot, very little voltage on the neutral and nothing on the ground. If the ground is showing voltage, that will definitely impact an amplifier with microprocessor controllers. 

Also, are you using the Kensington's earth ground? If so, disconnect it and see what happens.

@gs5556 

Thanks for the information. I will be sending the amp in for service.  Not using the Tannoy ground.  Also, the amp isn’t plugged into a wall AC. It runs from a Transparent PowerIsolator.  I tried it directly from the wall to no avail. Thanks again.