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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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16th Apr 2018, 11:20 am | #21 |
Hexode
Join Date: Dec 2009
Location: Leeds, West Yorkshire, UK.
Posts: 250
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Re: Transformer Failure - why?
Could C25 have been the cathode bypass cap for the output valves?
It's common to take the heater centre tap to the cathode of the output valves to raise the noise floor. Maybe when it was modified to fixed bias, this cap was overlooked and still in circuit but the resistor removed?
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16th Apr 2018, 3:34 pm | #22 |
Octode
Join Date: Jan 2003
Location: Guildford, Surrey, UK.
Posts: 1,960
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Re: Transformer Failure - why?
I think that biassing the heaters to a positive potential above the cathodes is a trick to prevent hum.
Ron |
16th Apr 2018, 3:38 pm | #23 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
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Re: Transformer Failure - why?
Thanks folks for that explanation.
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