Been using one here for a while drives a lot of speakers with ease and does sound much better with the ribbon cable disconected as mentioned in above post and works fine, i did think about fitting some standard spk terminals and throwing the top board away which i may still do if no takers as it is a good sounding amp for small to medium rooms, and i prefare to 306. its possible yours has a fault it should switch on and off as normal with board removed