DC300A hums

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#1 neuf

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Posted 21 January 2013 - 05:00 PM

My ole DC300A hums, not through the speakers...it just has a humming sound emanating from the amp.  I was looking for a pdf manual to see if there were any suggestions, but could not find an old user manual.  If anyone has any suggestions or a link to a manual, I would be most appreciative.


#2 bobbysdad


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Posted 21 January 2013 - 08:17 PM

It's the transformer that's humming but I just can't remember the fix.
(The ol' brain's just not it used to be.....)
Someone else is bound to step in with a solution.

In the meantime, you can find the manual for this (and other legacy amps) here: http://www.crownaudio.com/legacamp.htm

All the best...
I might be deaf, but I can still hear the bells......

#3 neuf

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Posted 22 January 2013 - 06:20 AM

Thank you for your response!  I got the manual.  You state "the ol' brain is not what it used to be..."  I noticed I posted this question a couple years ago.

#4 karlos the dc300a

karlos the dc300a

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Posted 15 February 2013 - 02:21 PM


Some dc300a amps had quite bad transformer hum, if the belly band around the tx is copper it shouldnt hum too bad, if its later aluminium band it will hum a lot more.

Best to make sure the transformer pimary has been set to correct mains voltage for your country.

You should have + / - 60v dc voltage rails inside the amplifier if the transformer primary has been configured correctly.

Often the primaries were set wrong resulting in an overloaded transformer and a bit more buzz than there should be.

good luck

#5 Crowndog


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Posted 25 March 2013 - 08:59 AM

toothpicks, the thin flat one's. Works every time.