Buzz when no inputs connected - OK?

[OneEyeDave]

I finished debugging my Crack today.  I'd like to verify one thing.  Is it expected (OK?) to hear a buzz when no input leads are connected?  The "no input" buzz gets louder as the volume increases.  Once input is connected or shorted there is no noise at full volume (well at least none that I can hear.)  From what I gathered from this forum, I expect this is behavior "normal" but wanted to make sure before installing the Speedball.

Thanks in advance!

 

[Paul Birkeland]

This is completely normal.

-PB

 

[Grainger49]

To test how quiet your Crack is either put in a pair of shorting plugs, posted by Dan in Technical Topics, or just short from the inner to outer conductors with a pair of alligator clip jumpers.  This isolates all outside influences, you only hear internally generated hum.  You might also hear some RFI picked up by the tubes.

 

[OneEyeDave]

Thank you!