Many old tubes sleep in my country
house, since the old times when my father used to build vacuum-tubes
radios in his green days. There are also lots of miniature 7-pin EF95
pentodes, that were used in high-frequency amps.
Now people round the globe is using
them for audio applications... so I decided to try out a low-anodic
voltage circuit. With small signals you can't drive the valve into
the distortion zone, therefore I added a FET stage. I've also
inserted a pot that moves the pentode's operating point, but its
effect can be noticed only at high distortion levels.
It works sweet, it's really easy to build – and it does not sound bad at all!
On stage I'm using it with a 'burglar alarm' type lead battery not to have to plug one more "brick" PS.
