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Posted to rec.antiques.radio+phono,sci.electronics.repair
Shoreline Electronics
 
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Default Marshall 4140 Amp question

What is the problem with the amp?

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Jeff Stielau
Shoreline Electronics Repair
344 East Main Street
Clinton,CT 06413
860-399-1861
860-664-3535 (fax)

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"n cook" wrote in message
...
I rarely deal with valve/tube amps and am more familiar with radio
output-matching transformers primary-windings having DC resistance of
windings of hundreds of ohms.
Been in a shed for years and no known history so treading cautiously.
Measuring the DC resistance of each side to centre tap of this Marshall
amp,
shows only about 15 ohm each way.
Amp is 100W o/p using 4 EL34 , two paralleled anodes going to each side of
this impedance matcher.
Does 15 ohm look right for each of these primary coils ?
Output resistance of about 2.5 and 4.5 for 4 and 8 ohm settings seems
fine.

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