Mike Knudsen asked about the Deleika 20-note organ.  The low pressure in
the reservoir indicates a definite leak in the system.  There should be
lots of reserve wind while playing the 20-note rolls.  Start by testing
each section, pumps, valves, etc., and determine exactly where the leak
is before doing any bellows work.

Re the bass Bourdons: to make them play softer you will have to re-
voice them by reducing the size of the slit (throat) at the pipes mouth.
Sometimes cardboard shims are used to space the block and cap; If not,
then the cap has to be removed and the block's lip built up again with
epoxy and filed down to the size you want.  The bigger the opening the
louder the pipe.  Its very easy to ruin a pipe forever, so use caution.
Here is Deleika's address.

  Deleika-Orgelbau GmbH
  Frankenstrasse 7
  74219 Moechmuehl-Zuettlingen
  GERMANY
  Fax/Phone 011 49 6298 4434

They only speak German but can read English, so a fax is best.
Hope this helps.

Ron Schmuck