[Amps] Need help with switch nomenclature

[TexasRF at aol.com]

Charles, you can also accomplish this by using three toggle switches.  The 
first one turns on the air supply, and supplies power to the second switch.  
The second switch supplies power to the filament and to the third switch. 
The  third switch supplies power to activate the high voltage.
 
Can't activate hv unless filament and air are on; can't activate filament  
unless air is on. At turn off, you can leave the air on for while longer if 
you  wish. A refinement is using double pole switches and wiring the ptt 
circuit in  series with all three switches to prevent keying the amplifier 
before everything  is turned on.
 
The hv on switch serves double duty as a standby switch in this case.
 
73,
Gerald K5GW
 
 
 
 
 
 
 
In a message dated 4/25/2013 11:50:40 A.M. Pacific Daylight Time,  
zedkay at telepak.net writes:



Way back in my foggy memory somewhere, I remember using and  amplifier 
made by B & W.   I think it was a "Model 1500",  but I'm not sure.  It 
used a pair of 813's.

What I remember as  unique about this amp was its "ON" or "POWER" 
switch. It used a rotary  switch to turn on the various functions one at a 
time.

In other  words:  Position 1 turned on the fan only. Position 2 kept 
the fan  on, and lit the filaments. Position 3 kept the previous two 
functions on,  and turned on the HV supply.

My question is, then:  What is this  kind of switch called?  I used 
one of these switches (salvaged from  an old tube tester) in my very 
first amplifier, and I'd like to use one  again, but for the life of 
me I can't find one from my usual parts sources  because I don't know 
what it's properly called.

It isn't "make  before break" because it never breaks the previous 
positions.  I  thought it would just be a "shorting type", but this is 
not the way any of  the "shorting type" switches offered for sale operate.

I'm  stumped!  Any help would be appreciated.

73,
Charles -  K5ZK

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