OK - I realize this was months ago - but anytime a Hafler amp does something strange but still makes distorted sound - check the protective fusses - these are usually easily accesible from the rear panel of the amp.
If memory ( a always fallible thing at my age) serves - these fuses where placed in the feedback loop - the idea was pretty good in that you didn't have a fuse in series with the speakers ( think about how strange the idea of hooking up garden hose diameter wire between amp and speakers is - if ALL this power is going thru a hair thin fuse filament wire?) Hafler got around this - but it does mean you will get distorted sound out of a Hafler amp when the protective fuse is blown.
Finally - check the B+ and B- rail fuses - in audio hell use (bars) - I've had customers blow rail fuses and still not suceed in blowing up DH series amps. and yes - beat on 'em enough and you can break 'em.
If memory ( a always fallible thing at my age) serves - these fuses where placed in the feedback loop - the idea was pretty good in that you didn't have a fuse in series with the speakers ( think about how strange the idea of hooking up garden hose diameter wire between amp and speakers is - if ALL this power is going thru a hair thin fuse filament wire?) Hafler got around this - but it does mean you will get distorted sound out of a Hafler amp when the protective fuse is blown.
Finally - check the B+ and B- rail fuses - in audio hell use (bars) - I've had customers blow rail fuses and still not suceed in blowing up DH series amps. and yes - beat on 'em enough and you can break 'em.