Ampico Function Switches
How They Work!
There are four types of Ampico Function Switches in the normal Ampico A player system. They are: the Replay 'On-Off' switch, the Pedal 'On-Off' switch, the Automatic (or Ampico) 'On-Off' switch, and the Brilliant/Normal/Subdue (or Modify) switch. Below are pictures of each switch along with an explanation of how the air is handled as it enters or leaves the switch. Note: These are all air-tight switches made from high quality brass which will provide multiple decades of trouble-free operation. To purchase a set of these new switches, click here.
This is the Replay 'On-Off' switch. In the 'Off' position, atmosphere, from the hole in the take-up spool, is allowed to pass from "B" to "A", which in turn activates the Automatic Shut-Off switch/pneumatic (the power on-off switch). At the same time, air is not allowed to pass through "C". In the 'On' position, atmosphere from the hole in the take-up spool, is allowed to pass from "B" to "C", which in turn activates the Replay valve/pneumatic. At the same time, air is not allowed to pass through "A", thus preventing the power from being turned off when the switch is in the Repeat position.
This is the Pedal 'On-Off' switch. In the 'Off' position, atmosphere from the Auto-Sustain hole on the trackerbar is not allowed to pass from "B" to "A", and the vacuum, from the Auto-Sustain device/valve, that is present at "A" is blocked from getting through the switch to "B". In other words, this is a "Pass" or "No-Pass" switch.
This is the Ampico 'On-Off' switch. In terms of its function, it too is a "Pass" or "No-Pass" switch. However, as is obvious, there is no nipple connected to "B". So, in the 'On' position, atmosphere is allowed to pass from "B" to "A", and in the 'Off' position. vacuum is prevented from passing through "A". This switch controls the operation of the Automatic Expression Cut Off Block.
This is the Brilliant/Normal/Subdue switch, which is better known as the Modify switch. It is a 3-position switch. In the Brilliant position, "B" is open to the atmosphere through "D", and "A" and "C" are closed. In the Normal position, "A", "B', and "C" are all closed. In the Subdue position, "A" and "C" are open to the atmosphere through "D" and "E" respectively, and "B" is closed. This switch controls the operation of the Amplifier Control Box ("B" open, "A" and "C" closed), and the Bass and Treble Subdue Regulating Pneumatics ("A" and "C" open, "B" closed).
Detailed information about how these switches are connected to the Ampico A system can be seen in the Model 'A' Ampico Tubing Chart (Rev. 1970), and information about how they function in the system can be found in the Ampico 'A' Service Manual (1919/w 1920 Supplement) and the Inspectors Reference Book (1923).