CV-591A/URR MODS by KH6GRT




Mine is not the greatest 'looker' but a great performer when used with a well working R-390A.

There are two mods I did on mine which improve its operation. These are completely reversible and do not change the appearance of the unit or require any holes to be drilled.

1. The first mod involves adding an additional amplifier in the IF signal path in the CV-591A. This mod allows the converter to run at less than maximum audio gain to achieve a comfortable listening level. This mod rewires V1B as an IF amplfier which was originally used as a diode and adds a silicon fast recovery diode in its place.

2. The second mod changes the BFO switch from a 2-position to a 3-position switch. The third position is to the right of the 'ON' position above. The extra position connects the low-level audio signal from the R-390A to the audio stages. This allows listening to a wider bandwidth signal from the R-390A over that afforded by just turning off the CV-591A BFO. This also eliminates having to run the R-390A line output to a separate speaker amplifier. This extra position need not be indicated on the front panel like above so as to retain original appearance. But YOU know it's there!

CV-591A Mods in .PDF format (Use your Adobe Reader 'BACK' arrow to return here.)


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