AudioBanter.com - View Single Post - Old Hobbyist Needs Amplifier Advice Please

"Sander deWaal" wrote in message
...
said:

Thanks.......I moved the amplifier to another cabinet, and when I
powered it back up, there was a loud hum out of the left channel.....I
subsequently found that one of the rail fuses had blown...I replaced
both fuses, powered the unit up, and it blew both fuses for the left
channel rail........

Hm.....can't be much wrong there, i'd say ;-)

One particular Hafler, a DH-120, had a design error.
The bias was derived from a string of power resistors that ran too hot.
When the lower resistor opened up, it would turn the outputs all the way on,
blowing the rail fuses.
No other Hafler has/had this design error.