In article ,
"Gareth Magennis" wrote:
Hi,
what is the purpose of the reverse biased diodes on the OPT/Cathodes as in
this Fender circuit?
http://www.schematicheaven.com/fende...er_60_rack.pdf
I need to replace a faulty one and am having difficulty sourcing the part
Fender use (R3000). Does this need to be a specific type of diode or can I
make up the 3kV diode required using standard 1Kv rectifier types?
I don't see any reversed biased diodes on the OPT/Cathodes, do you mean
the reversed biased diodes on the OPT/Anodes?
I believe the purpose of these diodes is to clamp the peak anode voltage
at twice the B+ voltage, limiting the magnitude of the high voltage
spikes that can be produced when the amp is overdriven into an inductive
load. These voltage spikes can destroy tubes and transformers if not
controlled.
Regards,
John Byrns
--
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http://fmamradios.com/