-=> Everett Hertenstein said to Greg Mayman
 -=> about "POWER SUPPLY [1/2]" on 01-24-04  19:52.....

 EH> If you're interested in knowing about it, a lot of the old pneumatic
 EH> controls on pipe organs are still in use.  I played one this week. 
 EH> Works nicely, but it's scheduled for conversion to
 EH> electronic/electromagnetic operation some time this year.

The "purists" still insist on tracker action for their organs as
that gives a direct connection from the keys to the air valves
for the pipes, and they say that is the only way you can get the
pipes to respond intimately to the way you operate the keys.

I read of one tracker action where the rods etc went from the
console on one side of a cathedral to the organ loft on the other
side, about 50 feet or more under the floor, with several changes
of direction on the way.

Then because the tracker action was too heavy on bigger organs,
they went to the pneumatic control, which was fine, except that
in many case there was quite a long delay between pressing the
keys and having the pipes sound. Imagine having to play one
second ahead of the music...

The electro-pneumatic was the best system, where the long
distance stuff was done electrically and the heavy stuff by
pneumatic relays. The delays were neglibly short, and comparable
with the delays in the sounding of the pipes.

I have an article about a fully electromagnetic operated organ
that pulled about 1 amp on each of the solenoids letting the air
into the pipes. It was built around 1900, IIRC, but the
limitations of the power supplies in those days made it
impracticable.

The big advantage with tracker, pneumatic and the simpler
electropneumatic organs is that someone with a bit of
intelligence just looking at it can work out how it is supposed
to operate.

And even if they've never seen anything like it before, there is
a fair chance they could restore a damaged one, just from what
they can see.

The hardest part in restoring this kinda stuff today is getting
the right kind of leather. Plastic is NOT an acceptable
substitute.

And the biggest problem with any electronic equipment is that
someone who doesn't know the item in question has very little
chance of working out how it is supposed to operate.

And as for restoring it in 100 years time... just forget it.

From Greg Mayman, in beautiful Adelaide, South Australia
   "Queen City of The South"    34:55 S  138:36 E

... A stumble may prevent a fall. - Thomas Fuller
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