[ Craig Roothoff wrote in 110626 MMDigest:
> Without multiple intensity perforations, the intensities are
> somewhat constricted on my piano. Lowest intensity is about 10 inches
> vacuum and highest is about 20 with source vacuum of about 30 inches.
Hi all, Craig Roothoof was inquiring about the expression system on
his small Recordo grand and wondering if it is providing its full
potential. The later Recordo systems did accommodate more possible
combinations than the earlier system, but if you examine a roll or two,
you will find a couple of things that are apparent.
Almost all of the time there is one dominant expression hole perforated.
There are seldom two expression holes perforated for more than, let's
say, three punches. These short expression holes are to provide a very
brief emphasis on a note or two.
You will also note that the split hammer rail on both bass and treble
are used much more than on the major reproducing systems for single
note de-emphasis (probably similar to the 0T "sub intensity" hole in
the Ampico B system).
Craig should realize that if he has a small grand it was probably built
to fit in a small apartment where a great volume of music was not
needed or desired and was probably used as background music.
I would suggest that Craig hook up his vacuum gauge at the stack once
more to determine if the system is providing it full potential. By
placing the tempo at zero and masking tape over the entire tracker bar,
record the vacuum levels at: no intensity hole open; #1 hole open; #2
hole open; #3 hole open; #4 hole open; bass hammer rail open; treble
hammer rail open.
Repeat these tests but briefly open one intensity higher and record
what the reading is (except for #4 when you should open #3 briefly).
You can then repeat the tests with the next two holes briefly open.
Craig can also record the vacuum level with all four intensities
activated. This way he will have a full set of data.
Mike Walter - former M. Schulz Recordo owner
Buffalo, New York
[ Bob Billings wrote that the Recordo system most commonly installed
[ is the 5-step Recordo ("B" type). The late 16-step ("C" type)
[ Recordo was installed around 1926 and later. He wrote:
[ "If one is not familiar with the various Recordo mechanisms, the
[ only way to tell for sure is to measure the stack vacuum while
[ opening the expression ports. If the vacuum increases when
[ a high level port is open and a lower level one is then opened,
[ it is a 16-step ("C")."
[ Ref. http://www.mmdigest.com/Archives/Digests/200005/2000.05.18.06.html
[ Typical vacuum gage readings for a 5-step Recordo are given at
[ -- Editor (Robbie)