I have a power amp (a Yamaha M-80) which is only specced to run at 110V/60Hz. I can get a stepdown transformer of adequate power rating easily, but it obviously doesn't alter the frequency. I'm ...

The ripple filter circuit is specially deisgned to filter out 50 Hz ripple signals from audio lines. A 50 Hz noise is usually found in european countries. In many cases, it is not possible to remove ...