Question about Roland Cube-20x (20w 8" Modeling Guitar Amp)

# The unit input voltage is 110 volt and was plugged into 220v outlet. . the input winding is now busted. . i was hoping to know the secondary voltage of the transformer. . i was planning to replace the tranformer with 220v input . thanks!

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• Roland Master

The winding is center tapped. It generates +/-24.5 volts DC. Based on it being a capacitor input filter, we need a peak voltage about 1 volt higher to account for the droop of the capacitor and the .7 volt drop of one silicon diode...

Since we need 25.5 volts peak then we need that divided by 1.414 RMS out of ONE side of the center=tapped secondary... So our secondary voltage is 18 volts either side of center.

You will need a 36 volt center-tapped secondary. Here is one that would work:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=162J36-ND

This has two 18 volt windings that you would connect in series and a dual primary you can set for either 120 or 240 input. About \$19 US.

Posted on Dec 29, 2010

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Posted on Jan 02, 2017

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