bias supply dropping resistor

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leleduke
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bias supply dropping resistor

Post by leleduke » Thu Feb 07, 2008 7:57 am

Why does the 50 watt instructions call for a 150K? I guess it depends on the trim pot value.
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Lou
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Post by Lou » Thu Feb 07, 2008 2:34 pm

I use 220K on my amp
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metalhead3ecr
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Re: bias supply dropping resistor

Post by metalhead3ecr » Tue Mar 05, 2013 10:30 am

sorry for the bump. But can anyone explain this to me? Thanks!

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neikeel
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Re: bias supply dropping resistor

Post by neikeel » Wed Mar 06, 2013 3:51 am

ac comes from the HT supply it has the resistor before the diode to protect it and keep bias voltage in correct range for your bias pot.
Original 50w using the Drake 1202-118 PT used 220k, earlier PT equipped 45s used 180k. No idea why the instructions say 150k !!
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metalhead3ecr
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Re: bias supply dropping resistor

Post by metalhead3ecr » Wed Mar 06, 2013 10:27 am

Thanks! I have a 150K in my 50watt which allows less voltage than a 220K would let in?

V=RI right?

:shrug:

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