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absolutepitch
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Joined: Jul 9 2006 - 8:58pm
Advice on Hafler DH-200 turn-off transient

Just got a Hafler DH-200 amp to check out. Checked the DC offset and it's very low, in the millivolts range. Hooked-up some low-cost speakers, and it plays. Took time to let it fully charge, and seems to sound good.

Only thing is that when I turn off the power switch on the front panel, there's a distinct pop or snap sound from the speakers. I don't recall Hafler amps doing this. I know the Dynaco amps did not d this. Does anyone remember if this is normal or not? The manual does not say anything on this. I would suspect bad disk caps across the power switch. Any suggestions?

jgossman
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DH-200

I have one that I completely recapped less the PS caps.  Did it before and after the rebuild.  It's never more than just a small thud.  Wouldn't sweat it.

jgossman
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Just a side note..

I was just inside my amp and thought about this post.  I reset the bias @ 350mA and resoldered a few connections.  Check your bias, check for cold joints and check the .045 caps at the inputs.

absolutepitch
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amp check

Thanks for the suggestions. I'll look into the manual for bias setting and then the caps check. I'm not clear on detecting cold joints, other than resoldering all of them.

Since the amp is circa 1980, maybe the power supply caps are getting old.

jgossman
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Could be

They are pretty rugged and over spec'd.  My feelings on Hafler PS Caps are they are very good and don'tget rid of them unless you need it.  If you go with say a Musical Concepts PS, keep the old in case you want to go back.

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