Regarding the automatic cut-out valve block and the associated
automatic on-off switch (sometimes called the Ampico on-off switch),
I'm trying to find out if all Ampico 'A' systems used a primary-type
valve (poppet-type) or a regular-type valve in the valve block.

I ask because the switches that I sell for the on-off function were
designed to allow atmosphere to trigger the valve (in the automatic
cut-out block), which in turn applies vacuum to the expression cut-out
block, when the on-off switch is in the 'On' position. However, if the
valve in the automatic cut-out valve block is a primary-type valve,
an atmosphere trigger would turn the vacuum to the expression cut-out
block 'off'. You can see that would be a 'problem'...

When I had the base and cap for the switch manufactured, I copied the
design of switches made by Bob Streicher, Don Teach, and Player Piano
Company (PPCo). However, I recently had a customer complain that,
in their Ampico 'A', the switch turns the expression 'off' when the
switch is in the 'On' position, which would indicate that the valve
in the automatic cut-out valve block is a primary-type valve.

Also, I've discovered that some of the earlier systems (like the
Stoddard Ampico in upright pianos) didn't have an automatic cut-out
valve block. Instead, the supply vacuum for the expression cut-out
block is turned 'on' and 'off' directly by the switch itself.

Any information you can provide about the conundrum will be appreciated.

Musically,
John A Tuttle
Brick, New Jersey, USA
Player-Care.com

[ MMD articles on this subject are indexed at
[ https://www.mmdigest.com/Archives/KWIC/C/cut-out.html 
[ and https://www.mmdigest.com/Archives/KWIC/C/cutout.html 
[ (Ampico literature uses the hyphenated word, "cut-out".)
[ In particular, see the articles by Bruce Clark. 
[ -- Robbie