The Player Piano Co. (Wichita KS) has, in the past, had problems
with various suction boxes. I seldom use them. But I just received
a couple in the mail and believe that they are the best suction box
I have ever used, that I didn't have to build myself.
The box seems to just hover at a reliable 8-10" of vacuum, and will
just stay there and barely growl at you. I really like that. The
difference seems to be using the proper triac in the motor control
They are quiet, well-built, and although they still have that 2-wire
switch (it should be a three wire switch to separate 'play' and
'reroll'), they are as reliable a unit as I have ever known about.
I can heartily recommend them to everybody!