[Amps] Need help with switch nomenclature

[Al Kozakiewicz]

"Rotary logic" had it's day - and its day has come and gone.

A rotary switch with a semicircular arc for the movable contact instead of a single finger was probably used.  You used to see all sorts of odd logic implemented in custom rotary switches back in the day when black wrinkletex and vacuum tubes were state of the art.

I'm with Ron.  God made diodes and relays (plus triacs and SCR's) to accomplish this sort of thing with post 1950s technology.

Al
AB2ZY

________________________________________
From: Amps [amps-bounces at contesting.com] On Behalf Of Ron Youvan [ka4inm at gmail.com]
Sent: Thursday, April 25, 2013 2:58 PM
To: amps at contesting.com
Subject: Re: [Amps] Need help with switch nomenclature

On 04/25/2013 02:50 PM, Charles Bibb - K5ZK wrote:

> 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.

   If you use DC relays to control everything, any non-shorting rotary
switch can be used with the addition of steering diodes.
--
   Ron  KA4INM - Youvan's corollary:
                 Every action results in unwanted side effects.
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