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Hafler 220, one channel out of sync HELP

Greetings, My older Hafler is showing some age and wear one of my channels is not operating at full capacity. I do get some sound out of it with a bit of distortion adn it fdoes respond to adjusting the volune. Changed the wiring witht the preamp and speakers around to make sure it wasn't somethimng easily replaceable but it's starting to look like time for Hafler salad surgery. Not really sure what to look for here, a new fuse change the transistors. Open for sound opinions and advice. Thanx much and have a great day, Terry
dickwettzles
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marakanetz's avatar
marakanetz
5,473 posts
 
Tubes you can rebias.
Transisors are biased only once by the manufacturer.
I'd suggest replacing an output devices along with bypass electrolytic capacitors.
jw94055
125 posts
 
Hafler Mosfets and cleaning. I saw a tweak on the internet about cleaning the the Mosfet pins and pin sockets. It must be done carefully but I must admit the difference was stunning. As they are not soldered in (anyway in my Hafler 200 they weren't), the pins and pin sockets get cruddy after 20 years. Again, caution is recommended in removing and cleaning. Still and all, the improvement in sound was well worth the effort and it costs only time. Good Luck. p.s. Get a copy of the Jung/Marsh POOGE article if you really want to dig into the Hafler.
marakanetz's avatar
marakanetz
5,473 posts
 
Solderless output???
I'd use solder in that case.
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