[ Joseph Osborne wrote in 150406 MMDigest --

> One problem I could not fix was a steady pitch vibration coming from
> right behind the belly rail, just under the soundboard, centered left
> to right (i.e. around note 44).

Hi Joseph,  This may not be your problem but I had similar troubles and
eventually found that I had not aligned the pump spill valve correctly.
If the vibration changes when the amplifier is operating that could be
a clue.

Jim Heyworth
Sechelt, British Columbia, Canada