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RME-69 power transformer




 
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Author Topic: RME-69 power transformer  (Read 538 times)
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no3m
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« on: October 18, 2017, 01:05:14 PM »

Anyone know the HV secondary specs on the RME-69 receiver power transformer?

Thanks
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N1BCG
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« Reply #1 on: October 20, 2017, 09:05:07 AM »

I contacted someone who has experience restoring RME receivers...

RME didnít document things thoroughly so I donít have any official specifications for the transformer and I also checked my Peter Dahl catalog but they never made a replacement for the RME receivers.  In terms of ratings the B+ secondary will need to be anywhere from 300-340 volts each side of center, that is 600 to 640 volts total secondary voltage with a center tap and the current rating should be 100 mils or greater.  You will need a separate 5 volt 2 amp winding for the type 80 filamentary cathode.  Both sides of the filament string in the RME-69 are held above ground and a center tapped filament winding is used for all except the 42 output tube which is on a separate filament winding HOWEVER I see no reason why you cannot feed all of the filaments (except the rectifier of course) from the same center tap filament winding as long as the current capability is sufficient.  I expect the separate filament winding for the output tube was a carryover from the RME-9D design which used 2.5 volt tubes with a correspondingly  higher filament current-especially with the 2A5 output tube which drew almost 2 amps by itself so breaking up the filament string made sense.

You do need to use a center tapped filament winding for hum reduction given the layout and wiring of the RME-69.  Hammond likely has something suitable.
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no3m
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« Reply #2 on: October 20, 2017, 03:53:17 PM »

N1BCG

Thank you.  I should be able to hunt something down.
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