This circuit is from a 1975 RCA tube manual. It appears elsewhere on the site. R5 depends on the voltage of the amplifier with which it is used and can be changed.
This circuit is from a Popular Electronics of December 1993. In it we have the way to externally connect...
With this power supply it is possible to use automotive devices with currents up to about 8A on the...
This circuit was found in a 80’s American documentation. The adjustment trimpot is from 47k to...